557 results on '"GROUT (Mortar)"'
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2. Corrosivity of water-soluble sulfate ions in simulated pore water solutions and different types of grout samples
- Author
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Lee, Seung-Kyoung
- Subjects
Electrolytic corrosion. ,Sulfates. ,Grout (Mortar) - Published
- 2021
3. Replaceable grouted external post-tensioned tendons.
- Author
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Ledesma, T.
- Subjects
Box girder bridges -- Design and construction. -- United States ,Tendons (Prestressed concrete) ,Post-tensioned prestressed concrete construction -- United States. ,Concrete bridges -- Corrosion -- United States. ,Concrete bridges -- Design and construction. -- United States ,Corrosion and anti-corrosives -- United States. ,Grout (Mortar) - Published
- 2019
4. Post-tensioned box girder design manual.
- Author
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Corven, John
- Subjects
Handbooks and manuals. ,Box girder bridges -- Handbooks, manuals, etc. -- Design and construction -- United States ,Post-tensioned prestressed concrete construction -- Handbooks, manuals, etc. ,Post-tensioned prestressed concrete -- Handbooks, manuals, etc. ,Grout (Mortar) ,Tendons (Prestressed concrete) - Published
- 2016
5. An FHWA special study : post-tensioning tendon grout chloride thresholds
- Author
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Lee, Seung-Kyoung
- Subjects
Prestressed concrete bridges -- Corrosion -- United States. ,Post-tensioned prestressed concrete construction -- Corrosion -- United States. ,Concrete bridges -- Maintenance and repair. -- United States ,Post-tensioned prestressed concrete. ,Grout (Mortar) - Published
- 2014
6. An FHWA special study : post-tensioning tendon grout chloride thresholds.
- Subjects
Concrete bridges -- Maintenance and repair. -- United States ,Post-tensioned prestressed concrete. ,Grout (Mortar) - Published
- 2014
7. Material characterization of field-cast connection grouts.
- Subjects
Prefabricated bridges -- Design and construction -- Testing. ,Precast concrete construction. ,Grout (Mortar) - Published
- 2013
8. Optimization on overall performance of Modified Ultrafine Cementitious Grout Materials (MUCG) and hydration mechanism analysis.
- Author
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Zhou, Junxia, Zha, Lanchang, Meng, Shiyu, and Zhang, Yu
- Subjects
- *
GROUT (Mortar) , *MULTIPLE regression analysis , *POLYVINYL alcohol , *SILICA fume , *X-ray diffraction - Abstract
Given the challenges encountered in injecting grout into micro-cracked rock masses, a modified ultrafine cementitious grout material (MUCG) was developed using ultrafine cement, polyvinyl alcohol (PVA) fibers, and a high-efficiency superplasticizer. To identify the optimal ratio of constituents for grouting these rock masses, extreme difference and multiple linear regression analyses were conducted based on test results of flowability and mechanical properties. A mix comprising 9% silica fume, 0.2% bentonite, 0.3% PVA fibers, 0.15% superplasticizer, and 2% setting accelerator was identified as the optimal mix. The microstructure characteristics of the optimal MUCG (MUCGop) grout cemented body were analyzed using XRD, FTIR, BET, and SEM. XRD and FTIR analyses indicated that a substantial amount of C-(A)S-H gel, CH, and AFt were formed within the first 3 days, highlighting the early strength characteristics of MUCGop. Over time, the content of C-A-H stabilized at 22%, the amount of CH decreased from 19% to 14%, whereas the amount of AFt increased to 15.9% by Day 28. Unexpectedly, CaCO3 content increased due to carbonation, reaching 37.3% by Day 28. BET and SEM analyses demonstrated that the specific surface area and porosity (most probable pore size) gradually decreased over time. At various ages, mesopores (cumulative pore diameter, median pore diameter) initially increased and then decreased. Micro-cracks appeared in the cemented body by Day 7, resulting in a slight decrease in strength (3.92%) from Day 3 to Day 7. The formation of well-developed needle-like AFt, C-(A)S-H gel, and small-volume plate-like CH contributed to uniform cementation and a denser structure. From Day 7 to Day 28, there was a slight increase in strength, by an amount of 10.66%. These findings have significant scientific implications for understanding the mechanisms of grouting reinforcement in micro-cracked rock masses. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Improvement of Soil Thermal Conductivity with Graphite-Based Conductive Cement Grouts.
- Author
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Cao, Benyi, Wang, Xueying, and Al-Tabbaa, Abir
- Subjects
- *
GROUT (Mortar) , *SHEAR strength of soils , *THERMAL conductivity , *GEOTHERMAL resources , *ENERGY industries - Abstract
Shallow geothermal energy systems (SGES) are a promising technology for contributing to the decarbonization of the energy sector. Soil thermal conductivity (λ) governs the heat transfer process in ground under a steady state; thereby, it is a key parameter for SGES performance. Soil mixing technology has been successful in enhancing the shear strength of soils, but is adopted in this paper for the first time to improve soils as a geothermal energy conductive medium for SGES applications. First, the thermal conductivity of six types of soils was systematically investigated and the key parameters analyzed. Next, graphite-based conductive cement grout was developed and mixed with the six soils in a controlled laboratory setting to demonstrate the significant increase in soil thermal conductivity. For example, the thermal conductivity of a very silty dry sand increased from 0.19 to 2.62 W/m·K (a remarkable 14-fold increase) when mixed with the conductive grout at a soil-to-grout ratio of 6∶1. In addition, the mechanical properties of the cement grouts and cement-mixed soils were examined along with the microstructural analysis, revealing the mechanism behind the thermal conductivity improvement. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. Effects of Polymer–Curing Agent Ratio on Rheological, Mechanical Properties and Chemical Characterization of Epoxy-Modified Cement Composite Grouting Materials.
- Author
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Wang, Yuxuan and Wu, Jiehao
- Subjects
- *
GROUT (Mortar) , *PARTICLE size distribution , *TUNNEL design & construction , *CEMENT composites , *EPOXY resins - Abstract
This study designs and uses water-borne epoxy resin (WBER) and curing agent (CA) to modify traditional cement-based grouting for tunnels. The purpose of this paper is to analyze the rheological and mechanical properties of composite grouting with different ratios of WBER and CA and analyze the modification mechanism by means of chemical characterization to explore the feasibility of WBER as a high-performance modifier for tunnel construction. The composite grouting is prepared by mixing cement paste with polymer emulsion. A series of experiments was carried out to investigate the effects of WBER and CA, including the slump test, viscosity, rheological curve, setting time, bleeding rate, grain size distribution, zeta potential, compressive and splitting tensile strength, X-ray diffraction(XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM), on the composite grout. The results show that WBER improves grout fluidity, which decreases in combination with CA, while also reducing the average particle size of the composite grout for a more rational size distribution. Optimal uniaxial (38.9%) and splitting tensile strength (48.7%) of the grout are achieved with a WBER to CA mass ratio of 2:1. WBER accelerates cement hydration, with the modification centered on the reaction between free Ca2+ and polymer-OH, significantly enhancing the strength, fluidity, and stability of the polymer-modified composite grout compared to traditional cement-based grouting. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. Ultimate Capacity and Load Transfer Mechanism of Ground Anchors in Granular Soils: State-of-the-Art.
- Author
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Al-Baghdadi, Nadher H. and Ahmed, Balqees A.
- Subjects
GROUT (Mortar) ,SOIL granularity ,TENSION loads ,SURFACE potential ,TENDONS - Abstract
Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
12. Comparison of Liquefaction Damage Reduction Performance of Sheet Pile and Grouting Method Applicable to Existing Structures Using 1-G Shaking Table.
- Author
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Yoon, Jong-Chan, Son, Su-Won, and Kim, Jin-Man
- Subjects
SHAKING table tests ,PORE water pressure ,STRUCTURED financial settlements ,GROUT (Mortar) ,GROUTING ,SOIL liquefaction - Abstract
This study conducted 1-G shaking table tests to compare methods of reducing liquefaction damage during earthquakes. The sheet pile and grouting methods were selected as applicable to existing structures. Model structures were manufactured for two-story buildings. A sine wave with an acceleration of 0.6 g and a frequency of 10 Hz was applied to the input wave. Certain experiments determined the effect of various sheet pile embedded depth ratios and grouting cement mixing ratios on reducing structural damage. The results confirmed that when the sheet pile embedded depth ratio was 0.75, the structure's settlement decreased by approximately 79% compared to the control model. When the grouting cement mixing ratio was 0.45, the structure's settlement decreased by approximately 85% compared to the untreated ground. In addition, the sheet pile method suppressed the increase in pore water pressure compared to the grouting method but tended to interfere with the dissipation of pore water pressure after liquefaction occurred. Additionally, comparing the effect of each method on reducing liquefaction damage revealed that the grouting method resulted in less settlement, rotation of the structure, and pore-water-pressure dissipation than the sheet pile method. Overall, the grouting method is more effective in reducing liquefaction damage than the sheet pile method. This study forms a basis for developing a liquefaction-damage reduction method applicable to existing structures in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
13. Dynamic modulus characteristics and prediction model of semi-flexible materials filled with high-performance cement paste.
- Author
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Deyong Wang, Guoxun Li, Lingang Jiang, Huaizhi Zhang, Jie Zhang, and Xiaowei Si
- Subjects
PREDICTION models ,FILLER materials ,ELASTICITY ,CEMENT ,GROUT (Mortar) ,PASTE ,ASPHALT pavements - Abstract
The dynamic modulus of asphalt mixture is an important factor in the design of asphalt pavement, and many scholars have proposed different models for estimating the dynamic modulus of asphalt mixture, but there are almost no studies on the prediction of the dynamic modulus of semi-flexible materials. In order to analyze and estimate the dynamic modulus of semi-flexible materials, we set up a high-performance cementitious paste (HPCP) semi-flexible material and a reference group Stone Mastic Asphalt (SMA-16) under multiple conditions, first measured its dynamic modulus in the laboratory, and analyzed the dynamic modulus characteristics of the material, and then used the equation the estimation equation proposed by Witczak et al. (Witczak1-37A) as a benchmark to introduce a new parameter, grouting mass ratio (Pb) to develop a Witczak- G prediction model to compare and validate the predicted dynamic modulus with the measured values. The results show that compared with SMA-16, HPCP semi-flexible material exhibits higher dynamic modulus and lower phase angle, and its temperature sensitivity and deformation resistance are significantly better than those of SMA-16. Under the influence of porosity and Pb factor, the dynamic modulus is positively correlated with both factors, and the phase angle increases first and then decreases, showing strong elastic properties. In this paper, we propose a dynamic modulus prediction model based on viscosity and Pb, Witczak-G, which predicts the highest coefficient of determination (R2) of the predicted dynamic modulus as high as 0.99 after initial fitting and validation, which indicates that the Witczak-G model is suitable for predicting the dynamic modulus of semi-flexible materials injected with HPCP. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
14. Tension Capacity of Crushed Limestone–Cement Grout.
- Author
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Dafalla, Muawia, Al-Mahbashi, Ahmed M., and Alnuaim, Ahmed
- Subjects
- *
GROUT (Mortar) , *STRAIN gages , *ELASTIC modulus , *COMPRESSIVE strength , *TENSILE strength - Abstract
The feasibility of using crushed limestone instead of sand in cement grout is examined in this work. This study entails performing several tests, including the Brazilian test, the compressive strength test, and the stress–strain correlation test. The curing times used were 7, 14, and 28 days for mixtures with various proportions of cement to limestone (1:1, 1:2, and 1:4). The conventional sand–cement grout laboratory tests were prepared using a similar methodology to examine the effectiveness of the suggested substitute. The findings show that the limestone-based grout has sufficient strength, but that it is less than that of the typical sand material. The values of the tensile strength and elastic modulus were determined. A focus was made on the tensile strength and stress–strain relationship. A special laboratory set-up was used to look at the progress of failure using strain gauges fitted to the cylindrical samples both vertically and horizontally. The angular shape of the particles' ability to interlock is responsible for the material's increase in strength. According to this study, crushed limestone can be used as a substitute for sand in circumstances where sand supply is constrained. The suggested grout can be used in the shotcrete of tunnels and rock surfaces. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Performance and mechanism of dual-network cementitious material formed by acrylamide monomer in-situ polymerization and ultra-fine portland cement.
- Author
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Yan, Shiao, Shao, Lijing, Shu, Liheng, Wang, Xiang, Shi, Bin, and Dong, Qiao
- Subjects
- *
PORTLAND cement , *CALCIUM silicates , *CEMENT admixtures , *ACRYLAMIDE , *GROUT (Mortar) , *CALCIUM silicate hydrate , *POLYMERIZATION , *MONOMERS , *CALCIUM hydroxide - Abstract
Grouting engineering is extensively employed in highway maintenance, tunnel excavation, mining, and other domains. As application scenarios become more complex, the demands for injectivity and toughness of grouting materials escalate. This research presents the fabrication of a dual-network cementitious material through acrylamide (AM) monomers in-situ polymerization and ultra-fine portland cement for grouting. The in-situ polymerization of AM increases the fluidity of cement paste, forms a hydrogel three-dimensional network structure, and significantly reduces the initial setting time from 345 to 35 min at a 5% AM content. The early-stage compressive strength (0–7 days) is inhibited by the in-situ polymerization, the flexural strength is notably increased, with an overall toughness improvement of 174.4% at a 7% AM content. The in-situ polymerization influences the early hydration behavior of ultra-fine portland cement by delaying the hydration induction period and affecting calcium hydroxide content and the bound water in calcium silicate hydrate. The complexation between metal ions (Ca2+, Al3+) in ultra-fine portland cement and carboxyl groups in the polymer enhances organic–inorganic interaction. The three-dimensional network structure of the cement hydration products and the polymer will form a dual-network structure, further enhancing the performance of the ultra-fine portland cement. In this research, the potential application of AM in-situ polymerization in the enhancement of ultra-fine portland cement grouting is proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
16. Influence of Coal Char Addition on the Heat of Hydration and Rheological Behavior of Cement Grout.
- Author
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Yu, Hua, Jonchhe, Prayush, Lau, Chooikim, and Ng, Kam
- Subjects
- *
GROUT (Mortar) , *HEAT of hydration , *CHAR , *COMBUSTION , *COAL combustion , *COAL - Abstract
Cement grout is widely used in underground excavations and constructions. Recent research reveals that coal char, a sustainable coal-derived material, can enhance the engineering properties of traditional cement grouts, such as higher compressive strength and lower bleeding at room temperature. However, the effect of coal char addition on the heat of hydration and rheological behaviors of char-cement grouts at lower or higher temperatures remains unclear. In this study, considering different w/c ratios (0.8–1.2) and char contents (10%–30%), the heat of hydration of char-cement is investigated to understand the hydration mechanism of cement with adding char. The rheological behaviors of new char-cement grouts at two different temperatures of 5 and 35°C are studied. It is found that the addition of char at the same w/c ratio leads to a higher first heat flow peak in the initial reaction period and facilitates hydration reaction in cement grouts based on cumulative heat evolution over a longer period (typically >14 h). The effect of 5 and 35°C on rheological behaviors of char-cement grouts is consistent with the respective pure cement grouts. A simple model based on cumulative flow resistance is proposed for describing the rheological behavior and can well fit all pure cement and char-cement grouts with a relatively high average R2 value of 99.7%. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
17. 基于 RSM 的超细水泥注浆材料配比及性能优化模型.
- Author
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刘伟韬, 吴海凤, and 申建军
- Subjects
GROUT (Mortar) ,WATER damage ,MINE water ,COMPRESSIVE strength ,SILICA fume - Abstract
Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
18. Design and Application of Mortars and Grouts for the Restoration of the Byzantine Church of Panaghia Krena in Chios Island, Greece.
- Author
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Miltiadou-Fezans, Androniki, Kalagri, Anna, and Anagnostopoulou, Sophie
- Subjects
GROUT (Mortar) ,PRESERVATION of churches ,LIME (Minerals) ,MATERIALS texture ,CERAMIC tiles ,MORTAR - Abstract
The Church of Panaghia Krena is a very important Byzantine monument situated in the island of Chios, well-known due to the high aesthetic value of the ceramic tile decoration on its facades and of its frescoes. The church suffered severe damage especially due to the 1881 devastating Chios earthquake and different interventions were implemented soon after (1884), consisting mainly of the reconstruction of collapsed areas and the addition of ties. Nevertheless, deterioration of old damages and appearance of new ones was observed. Thus, a restoration program was carried out between 2000 and 2007. This paper presents the basic characteristics of all types of historic materials examined, the main results of the in situ and laboratory experimental program carried out for the selection of the raw materials, and the design of optimum compositions of mortars and grouts to be used for the restoration works. The importance of in situ pilot applications is underlined, as well as of the production of site-specific aggregates for the repointing mortars by crushing a local rock, in order to succeed the adequate reddish color to match with the original mortars and bricks still preserved and achieve an aesthetic harmony with the color hue and texture of the original materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. 聚丙烯纤维改性超细水泥复合注浆材料性能研究.
- Author
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曾熙文, 王艳芬, 赵光明, 程详, 艾洁, 李英明, and 孟祥瑞
- Subjects
MECHANICAL loads ,BINDING agents ,GROUT (Mortar) ,ACOUSTIC emission ,POLYPROPYLENE fibers - Abstract
Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
20. In situ experimental study of vibration reduction using thick concrete slabs with natural and cement-improved subgrade.
- Author
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Xu, Zhaogang, Lou, Yu, and Chen, Liu
- Subjects
- *
CONCRETE slabs , *BUILDING foundations , *GROUT (Mortar) , *CONSTRUCTION slabs , *SOIL vibration - Abstract
Thickening the foundation slab and improving the subgrade soil using geo-techniques are effective measures for controlling unwanted vibrations at high-tech facilities. In this study, the vibration-reduction performance of 1-m-thick concrete slabs with natural and cement-improved subgrades was investigated based on in situ frequency sweep tests. One 1-m-thick concrete slab rested on 1-m-thick compacted sandy gravel backfill atop an undisturbed subgrade was constructed on the north side of the experimental site, and another identical concrete slab rested on 1-m-thick compacted sandy gravel backfill atop a cement-improved subgrade was constructed on the south side. The vibration-reduction effect was evaluated by comparing the free-field ground vibrations and surface vibrations of the two slabs at three pairs of evaluation locations. In terms of peak velocity, the 1-m-thick concrete slab with the natural subgrade exhibited a slight vibration amplification effect at low frequencies and a significant reduction effect at middle and high frequencies; the 1-m-thick concrete slab with the cement-improved subgrade exhibited a continuous vibration reduction action at all frequencies. In terms of RMS velocity, the vibration-reduction performance of the 1-m-thick concrete slab with the cement-improved subgrade was better than that with the natural subgrade. The results demonstrated that the vibration-reduction effect of the thick concrete slab was significant and could be increased by improving the subgrade using the cement grouting method. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Properties and Microstructure of a Cement-Based Capillary Crystalline Waterproofing Grouting Material.
- Author
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Wang, Mengjie, Yang, Xiaohua, Zheng, Kunlong, and Chen, Rui
- Subjects
GROUTING ,GROUT (Mortar) ,WATERPROOFING ,WATER leakage ,CAPILLARIES - Abstract
Cement grout is traditionally used for treating water leakage distress in tunnels. However, traditional cement grout has the disadvantages of a poor anti-seepage performance, long setting time, and slow strength gain. To this end, a high-performance cement-based capillary crystalline waterproofing (CCCW) grouting material was synthesized using cement, capillary crystalline material, and several admixtures. The influences of the material proportions on the viscosity, bleeding rate, and setting time of the fresh grout, as well as the permeability coefficient of the grouted aggregate and the unconfined compression strength of the hardened grout material, were systematically studied. The mineralogy and microstructure of the CCCW grouting material were examined using X-ray diffraction, industrial computed tomography, and scanning electron microscopy. The results indicated that the capillary crystalline material PNC803 was not suitable for mixing with bentonite, sodium chloride, and triethanolamine in cementitious slurries, but it can produce excellent synergistic effects with sulfate, calcium chloride, and triisopropanolamine. An analysis of the microstructure of the CCCW grouting material showed that the PNC803 and additives can promote the hydration of cement, which yields more hydration products, sealing water passage and filling micro voids and therefore leading to enhanced waterproofing and strengthening effects. These research results could improve the applicability of CCCW material in tunnel engineering. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Influence of Materials of Moulds and Geometry of Specimens on Mechanical Properties of Grouts Based on Ultrafine Hydraulic Binder.
- Author
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Hortigon, Beatriz, Rodriguez-Mayorga, Esperanza, Santiago-Espinal, Jose Antonio, Ancio, Fernando, and Gallardo, Jose Maria
- Subjects
- *
GROUT (Mortar) , *GROUTING , *CEMENT , *FLEXURAL strength , *COMPRESSIVE strength , *EXPANSION & contraction of concrete - Abstract
Ultrafine hydraulic binder grout injection is a technique utilised for repairing masonry, either to connect sections, seal joints, or fill voids due to its great capacity for penetration and higher mechanical strength than lime grout. In this research, the mechanical properties of ultrafine hydraulic cement grout are analysed considering the influence of the mould material for preparing the specimens and their geometry characteristics in the context of the specifications set out in several international standards. The test campaign to ascertain compressive and flexural strength in different circumstances is supplemented with a physical and chemical characterisation of both binder and fresh and hardened grout. Significant differences in mechanical properties between specimens prepared with absorbent or non-absorbent-water material are found due to the influence of drying shrinkage and decanting binder during the curing process. Furthermore, the slenderness of specimens is presented as an important factor in determining the compressive strength of mixtures. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Utilizing Crushed Limestone as a Sustainable Alternative in Shotcrete Applications.
- Author
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Mutaz, Elamin, Dafalla, Muawia, Al-Mahbashi, Ahmed M., and Serati, Mehdi
- Subjects
- *
SHOTCRETE , *LIMESTONE , *GROUT (Mortar) , *RAW materials , *CLEAN energy - Abstract
Solving the challenges facing the mining industry is crucial for shaping the global attitude towards clean energy technologies associated with critical minerals extracted from depth. One of these challenges is the well-known explosion-like fractures (rockbursts) or spalling failures associated with the initiation of internal cracks. To prevent such catastrophic failure, shotcrete, as a cement grout, is widely used in tunnel support applications. In areas where the tunnels are constructed within the limestone strata using tunnel boring machines (TBM), drilling, and/or blasting, millions of cubic meters of crushed limestone (CL) in powder form are extracted and landfilled as waste. Given the fact that natural sand consumption as a raw material in the construction industry exceeds previous records, recycling of such excavation material is now becoming increasingly needed. From this perspective, this study aims to utilize crushed limestone as a potentially sustainable alternative to natural sand in shotcrete applications in deep tunnels. Accordingly, several strength characterization and crack initiation determinations through various stress–strain-based models were carried out on cylindrical samples containing different proportions of crushed limestone. By increasing the crushed limestone content in the shotcrete mix, the crack initiation stress (as a measure of the in situ spalling strength) increased as well. The results suggest that the crushed limestone has good potential to replace the natural sand in the shotcrete mixture used in tunnel support applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Study on the Hydrochemical Characteristics and Evolution Law of Taiyuan Formation Limestone Water under the Influence of Grouting with Fly Ash Cement: A Case Study in Gubei Coal Mine of Huainan, China.
- Author
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Xiao, Guanhong and Lu, Haifeng
- Subjects
FLY ash ,COAL mining ,GROUTING ,GROUT (Mortar) ,MINE water ,LIMESTONE ,PORTLAND cement ,DOLOMITE - Abstract
The hydrogeological conditions of Huainan Coalfield are complex. The Taiyuan formation limestone water (Taihui water) in this area is a direct threat to the water source of the 1# coal mining floor. In order to prevent and control water disasters, Gubei Coal Mine adopted ground high-pressure grouting with fly ash cement to block the hydraulic connection between the Taiyuan formation limestone aquifer and the Ordovician limestone aquifer. However, the injected slurry will destroy the original hydrochemical balance of Taihui water and change its hydrochemical characteristics. Taking the influence area of the 2# karst collapse column in the Beiyi 1# coal mining area of Gubei Coal Mine as an example, a total of 25 Taihui water samples were collected. The hydrochemical characteristics and evolution law of Taihui water before and after grouting are studied via the multivariate statistical method. The research methods include constant index statistics, Piper diagram, correlation analysis, ion combination ratio, and saturation index analysis. The results show that after grouting, the concentrations of Na
+ + K+ , Ca2+ , Mg2+ , and Cl− in Taihui water decrease, while the concentrations of SO4 2− and HCO3 − increase. The average values of PH and TDS become larger. The hydrochemical types of Taihui water are more concentrated, mainly HCO3 -Na and Cl-Na. The correlations between conventional indicators decrease. According to the analysis of ion combination ratio, dissolution, cation exchange, and pyrite oxidation mainly occur in Taihui water, and these effects are enhanced after grouting. The saturation index results show that after grouting, the saturation index of dolomite, calcite, and gypsum is significantly reduced, and the saturation index of rock salt is slightly increased. The conclusion of this study is that the hydrochemical characteristics of Taihui water are greatly affected by fly ash cement. Moreover, because fly ash cement contains a lower calcium oxide content than ordinary Portland cement, the effect of fly ash cement on the ion concentration of Taihui water and the resulting hydrogeochemical effect are significantly different. Therefore, in the treatment of mine water disasters, the hydrogeochemical evolution law affected by fly ash cement grouting should be identified. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
25. Joint Behavior of Full-Scale Precast Concrete Pipe Infrastructure: Experimental and Numerical Analysis.
- Author
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Basit, Abdul, Abbas, Safeer, Ajmal, Muhammad Mubashir, Mughal, Ubaid Ahmad, Kazmi, Syed Minhaj Saleem, and Munir, Muhammad Junaid
- Subjects
PRECAST concrete ,NUMERICAL analysis ,MORTAR ,MATERIALS testing ,GROUT (Mortar) ,SEWER pipes - Abstract
This study undertakes a comprehensive experimental and numerical analysis of the structural integrity of buried RC sewerage pipes, focusing on the performance of two distinct jointing materials: cement mortar and non-shrinkage grout. Through joint shear tests on full-scale sewer pipes under single point loading conditions, notable effects on the crown and invert of the joint were observed, highlighting the critical vulnerability of these structures to internal and external pressures. Two materials—cement–sand mortar and non-shrinkage grout—were used in RC pipe joints to experimentally evaluate the joint strength of the sewerage pipes. Among the materials tested, cement–sand mortar emerged as the superior choice, demonstrating the ability to sustain higher loads up to 25.60 kN, proving its cost-effectiveness and versatility for use in various locations within RC pipe joints. Conversely, non-shrinkage grout exhibited the lowest ultimate failure load, i.e., 21.50 kN, emphasizing the importance of material selection in enhancing the resilience and durability of urban infrastructure. A 3D finite element (FE) analysis was also employed to assess the effect of various factors on stress distribution and joint deformation. The findings revealed a 10% divergence between the experimental and numerical data regarding the ultimate load capacity of pipe joints, with experimental tests indicating a 25.60 kN ultimate load and numerical simulations showing a 23.27 kN ultimate load. Despite this discrepancy, the close concordance between the two sets of data underscores the utility of numerical simulations in predicting the behavior of pipe joints accurately. This study provides valuable insights into the selection and application of jointing materials in sewerage systems, aiming to improve the structural integrity and longevity of such critical infrastructure. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Exploration on electrical resistance tomography in characterizing the slurry spatial distribution in cemented granular materials.
- Author
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Wang, Bohao, Wang, Wei, Jin, Feng, Tan, Handong, Liu, Ning, and Huang, Duruo
- Subjects
ELECTRICAL resistance tomography ,GROUT (Mortar) ,GROUTING ,BOND strengths ,SLURRY - Abstract
This study investigated the application of electrical resistance tomography (ERT) in characterizing the slurry spatial distribution in cemented granular materials (CGMs). For CGM formed by self-flow grouting, the voids in the accumulation are only partially filled and the bond strength is often limited, which results in difficulty in obtaining in situ samples for quality evaluation. Therefore, it is usually infeasible to evaluate the grouting effect or monitor the slurry spatial distribution by a mechanical method. In this research, the process of grouting cement paste into high alumina ceramic beads (HACB) accumulation is reliably monitored with ERT. It shows that ERT results can be used to calculate the cement paste volume in the HACB accumulation, based on calibrating the saturation exponent n in Archie's law. The results support the feasibility of ERT as an imaging tool in CGM characterization and may provide guidance for engineering applications in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. EFFECT OF EPOXY RESIN AND CEMENT AS GROUT ON THE MECHANICAL PROPERTIES OF SILT.
- Author
-
Latif, Devi Oktaviana, Kumala, Suraida Nur, Purnama, Adhitya Yoga, Haryanto, Iman, Aini, Rafa Amatullah, and Al Mubarok Kaluku, Zuhair Hafidz
- Subjects
GROUT (Mortar) ,EPOXY resins ,BUILDING foundations ,SILT ,FILLER materials ,MODULUS of elasticity - Abstract
Grouting is a method or technique that is carried out to improve underground conditions by injecting material that is still in a liquid state, through pressure (it can inject semi-viscous materials) so that the material will fill in all the existing cracks and holes. The main purpose of grouting in this study is to strengthen the soil and increase soil strength. The injection material will enter the soil pores, react with the soil, and harden to form a strong and sturdy bond. The grouting material in this study was applied to filling boreholes in pile foundations when a load is applied, will be held by the frictional resistance between the piles, cement, epoxy paste, and soil. The filling materials for this grouting are soil paste, cement, and epoxy resin which were observed in a laboratory with a tensile test system to see the behavior of increasing soil strength at 7 days, 14 days, and 28 days. Based on the results of laboratory tests carried out, the use of epoxy resin, cement, soil, and water as grouting materials for foundations increases the soil stiffness value expressed in the modulus of elasticity value and increases the soil shear parameter values, namely the values c and f. The increase in value occurs at the ratio ER/W = 80/180 where with a longer curing time, namely 28 days, the value of shear stress, c and f and the modulus of elasticity are each 2.3kg/cm2; 39,520; 12.08 MPa. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Effect of sulfate erosion on shear characteristics of slurry-reinforced coal body structural faces.
- Author
-
Ren, Zhiwei, Wang, Jun, Ning, Jianguo, Zhang, Shuai, Hu, Hao, and Bian, Yongtian
- Subjects
- *
SHEAR (Mechanics) , *EROSION , *SLURRY , *COAL , *GROUT (Mortar) , *SHEAR strength , *CAVITATION erosion - Abstract
To study the effect of sulfate ion erosion on grouted reinforced coal bodies, downhole grouting reinforcement was simulated by artificially prefabricating regular serrated structural surfaces and grouting them with cement. In addition, sulfate erosion tests were carried out at three erosion ion concentrations (3%, 5%, and 10%) and four erosion times (7d, 14d, 28d, and 40d) at a pressure of 0.2 MPa using self-developed constant pressure accelerated erosion equipment, and then, mechanical property tests were conducted using an MTS816 rock mechanics shear tester, which is the most effective way to test the mechanical properties of coal. The test results are as follows: (1) the shear stress–displacement curves of the specimens were of slip type at lower normal stresses and of peak shear type at higher normal stresses, (2) the shear strength of the specimen was linearly negatively correlated with the erosion time and erosion ion concentration, (3) the effect of erosion time was greater than the effect of erosion concentration on the specimen shear strength parameters, (4) sulfate erosion can only affect the degree of shear shrinkage and shear rise and cannot change the damage behavior, and (5) with an increase in erosion ion concentration and the prolongation of the erosion time, the damage morphology of the specimen was shown as the "coal body destruction–nipping fracture–climbing nipping fracture" (coal–pulp interfacial separation) damage form. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Microbial cement grout anchoring steel reinforcement pull-out test.
- Author
-
Jia, Qiang and Zhang, Tianjian
- Subjects
- *
GROUT (Mortar) , *REINFORCING bars , *CONCRETE joints , *SAND , *STEEL bars - Abstract
Microbial cement, known for its superior fluidity, stable crystal formation, and strong bond with concrete, is an effective solution in fixing defects such as voids that appear due to insufficient grouting in the joints of precast concrete components. To evaluate the mechanical properties of rebar anchored with microbial cement grout, three pull-out tests were designed, taking into account parameters such as calcium source concentration, the filler in borehole voids, and the shape of the rebar. The results indicate that specimens with a higher concentration of calcium source require fewer grouting cycles, but the pull-out bearing capacity of the anchored rebar is lower. However, the introduction of quartz sand as a filler in the borehole voids results in a significant increase in the pull-out bearing capacity of the rebar compared to specimens without filler. Among these, the specimens with a medium particle size of 0.5 ~ 1 mm (1/4δ ~ 1/2δ, the gap of δ = 2 mm between the steel bars and hole wall) have the highest pull-out bearing capacity. In comparing rebar shapes, ribbed rebar slightly outperforms smooth round rebar in terms of pull-out bearing capacity. Based on the experimental results analysis, the anchoring mechanism of microbial cement grouting on reinforcement has been elucidated. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
30. Study on Vertical Bearing Capacity of Pile Foundation with Distributed Geopolymer Post-Grouting on Pile Side.
- Author
-
Li, Pan, Xia, Yangyang, Xie, Xinhui, Wang, Jing, Wang, Chaojie, Shi, Mingsheng, Wang, Bo, and Wu, Haoye
- Subjects
- *
BUILDING foundations , *BORED piles , *GROUT (Mortar) , *PORTLAND cement , *GROUTING , *POLYMER-impregnated concrete - Abstract
To study the applicability of the new geopolymer grouting material for super-long and large-diameter post-grouting bored piles in silty fine sand geology, this paper compares the bearing capacity of two grouting materials, geopolymer and normal Portland cement, and different grouting volume pile side-distributed grouting piles in silty fine sand based on field model tests are analyzed through the diffusion forms of the two materials in silty fine sand through the morphology of the grouted body after excavation. The results show that the ultimate bearing capacities of P0 (ungrouted pile), P1 (8 kg cement grouted pile), P2 (6 kg geopolymer-grouted pile), P3 (8 kg geopolymer-grouted pile) and P4 (10 kg geopolymer-grouted pile) are 5400 N, 8820 N, 9450 N, 11,700 N and 12,600 N, respectively, and that the ultimate bearing capacity of the grouted pile is improved compared with that of the ungrouted pile since, under the same grouting amount, the maximum bearing capacity of the pile using geopolymer grouting is increased by 133% compared with that of the pile with cement grouting. This further verifies the applicability of the geopolymer grouting material for the post-grouting of the pile foundation in silty fine sand. Under the action of the ultimate load, the pile side friction resistance of P1, P2, P3 and P4 is increased by 200%, 218%, 284% and 319% compared with that of P0. In addition, the excavation results show that the geopolymer post-grouting pile forms the ellipsoidal consolidation body at the pile side grouting location, which mainly comprises extrusion diffusion with a small amount of infiltration diffusion, and the cement grouting pile forms a sheet-like consolidation body at the lower grouting location, which primarily comprises split diffusion. This study can provide a reference basis for the theoretical and engineering application of post-grouting piles using geopolymers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. A Multi-Depth Deflectometer/Global Navigation Satellite System Method for Measuring Concrete Slab Track Deformation.
- Author
-
Bahati, Pierre Anthyme, Le, Viet Dinh, and Lim, Yujin
- Subjects
GLOBAL Positioning System ,CONCRETE slabs ,CONSTRUCTION slabs ,TUNNELS ,GROUT (Mortar) - Abstract
This study introduces a Multi-Depth Deflectometer (MDD) combined with a Global Navigation Satellite System (GNSS) which was developed for measuring the deformation of railway slab track layers. We newly designed the MDD with the addition of laser sensor modules for increasing precision in which the MDD head is fixed at the top of the track slab. The MDD/GNSS system can measure the relative deflection between each track layer as well as the total deflection at the top of the track slab, which makes it possible to evade the fixed condition problem of classical MDD. The new MDD/GNSS system was installed at the transition zone between a tunnel entrance and its embankment, which experienced high settlement levels prior to repair. The system was used to monitor whether the repaired concrete track foundation with pressurized cement grouting was stabilized effectively and what track layer position was most unstable so that it had the most influence. The GNSS system was designed and built for computing net settlement at each track layer even when the MDD could not be fixed firmly at the end point, which is a major drawback of classical MDD. The results obtained from MDD and GNSS measurements indicated significant potential in aiding railway track settlement measurements. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing.
- Author
-
Permeh, Samanbar and Lau, Kingsley
- Subjects
CORROSION & anti-corrosives ,THIXOTROPIC gels ,ROBUST control ,STEEL corrosion ,GROUT (Mortar) - Abstract
The corrosion of steel in post-tensioned tendons has been associated with deficient grout materials containing high free sulfate ion concentrations. In a Florida bridge in 2011, tendon corrosion failures occurred for a prepackaged thixotropic grout that had developed material segregation. However, the available grout and corrosion testing prescribed in material specifications, such as grout bleed water testing, was not able to identify the propensity or modality for the grout deficiencies and the associated steel corrosion that was observed in the field. It was of interest to identify corrosion testing methods that could prescribe grout resistance to segregation-related deficiencies that can form by aberrations in construction. The objectives of the work presented here included (1) characterizing the development of physical and chemical grout deficiencies due to excess mix water and water volume displacement, (2) developing small scale test methodologies that identify deficient grout, and (3) developing test methodologies to identify steel corrosion in deficient grout. The inverted-tee test (INT) and a modified incline-tube (MIT) test were assessed and both were shown to be useful to identify the robustness of grout materials to adverse mixing conditions (such as overwatering and pre-hydration) by parameters such as sulfate content, moisture content, electrical resistance, and steel corrosion behavior. It was shown that the different grout products have widely different propensities for segregation and accumulation of sulfate ions but adverse grout mixing practices promoted the development of grout deficiencies, including the accumulation of sulfate ions. Corrosion potentials of steel < −300 mV
CSE developed in the deficient grout with higher sulfate concentrations. Likewise, the corrosion current density showed generally high values of >0.1 μA/cm2 in the deficient grouts. The values produced from the test program here were consistent with historical data from earlier research that indicated corrosion conditions of steel in deficient grout with >0.7 mg/g sulfate, further verifying the adverse effects of elevated sulfate ion concentrations in the segregated grout. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
33. Structural layer applicability of semi-flexible material for rutting resistance: A coupled temperature-mechanical approach.
- Author
-
Yu, Maohua, He, Tianming, Xu, Kejian, Cheng, Hong, and Ren, Minda
- Subjects
- *
PAVEMENT testing , *STRENGTH of materials , *ASPHALT concrete , *ASPHALT pavements , *GROUT (Mortar) , *ASPHALT - Abstract
Semi-flexible material (SFM) is produced by pouring cement grouting material into the asphalt concrete skeleton. It exhibits both characteristics of cement and asphalt, increasing structural stiffness and reducing rutting. Extensive studies have shown that the temperature load coupling effect is one of the leading causes of road rutting. However, few researchers focused on the anti-rutting impact and structural layer applicability of SFM under this effect. Thus, a coupled temperature-mechanical approach was developed based on the finite element (FE) method to simulate the rutting of SFM at different pavement layers and times of the day. During simulation, both standard load and overload were applied to the FE model of pavement. Asphalt mixture and SFM specimens were prepared for essential road performance and dynamic modulus testing. The mechanical properties of SFM and asphalt mixtures at different temperatures were obtained based on the measured data. The structural layer applicability of SFM was revealed by simulating the response of the pavement structure under the combined action of temperature and load. An accelerated pavement test (APT) based validation indicated that the simulation results were accurate. The results show that traditional asphalt pavement and pavement with SFM at the surface and bottom layers tend to exhibit dilative heave adjacent to the wheel load. Using SFM at the middle layer shows a compacted rutting mode, and the pavement has a minimum rise of 51% in rutting depth under the double overloading compared with the pavements with SFM in other layers. It implies that using SFM in the middle layer gives optimal resistance to overload. Considering the depth, form, and resistance of rutting, the SFM in the middle layer of pavement can functionally exert its anti-rutting characteristic. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Mechanical and Acoustic Emission Characteristics of Grouted Reinforcement in Fissure-Containing Rock-like Specimens.
- Author
-
Yu, Zhonglin and Song, Chenchen
- Subjects
ACOUSTIC emission ,SURFACE fault ruptures ,ACOUSTIC emission testing ,GROUT (Mortar) ,CEMENT slurry ,GROUTING - Abstract
In order to study the reinforcing effect of the different grouting materials applied in fissure rock engineering, ultra-fine cement slurry, cement–silicate slurry, and MARITHAN
® were used to carry out grouting tests on specimens of fissure-containing rocks. With the help of a uniaxial compression acoustic emission test system, the mechanical characteristics of the grouted specimens were obtained, and the damage process of the specimens was revealed by using the acoustic emission signals. The tested results showed the following: the residual strength of the grouted specimens using the three grouting materials increased by 16.931%, 13.075%, and 39.998%, respectively; the ultra-fine cement grouting and cement–silicate grouting specimens showed damage patterns of shear-slip damage along the original rupture surface; the specimens of MARITHAN® grouting cracked from a position near the end of the specimen with no damage to the grouted body portion; the cumulative acoustic emission energy curves of the grouted specimens showed obvious stage characteristics; and the acoustic emission energy distribution characteristics of the grouted specimens differed depending on the grouting materials. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
35. Performance of the Cement Grouting Material and Optimization of the Mix Proportion for the Free Section of the Prestressed Anchor Bar.
- Author
-
Wu, Chaoguang, Chen, Zhiya, Zhang, Xuemin, Li, Zikun, Wang, Lichuan, Ouyang, Bin, and Liu, Jin
- Subjects
- *
GROUT (Mortar) , *CEMENT slurry , *COMPRESSIVE strength , *SLURRY , *ANCHORS , *GROUTING - Abstract
Increasing the water–cement ratio and water-reducer dosage of cement slurry enhances its fluidity. However, a high water–cement ratio diminishes the beneficial effects of water reducers on fluidity. The stone content of the slurry decreases as the water-reducer dosage increases. Additionally, the water–cement ratio significantly affects stone content. However, when the water–cement ratio exceeds a threshold value, stone content decreases. Furthermore, the threshold value of the water–cement ratio decreases with increasing water-reducer dosage. Without the addition of the water reducer, as the water–cement ratio increases the overall integrity of the grout stone decreases. The addition of the water reducer alters the surface pore distribution, wherein "uniform small pores" change to "localized large pores." Based on the multi-objective optimization of Matlab, the recommended optimal mix composition for a slow-setting cement slurry is a water–cement ratio of 0.25 and water-reducer dosage of 1.5%. With the use of this optimized mix composition, the stone content and compressive strength increase by 7.8% and 145.6%, respectively, compared to those obtained using the recommended mix ratio in the specifications. Additionally, all relevant performance parameters meet the requirements specified by previous standards. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. A Study on the Load-Bearing Characteristics and Load Transfer Mechanism of Bag Grouting Pile in Soft Soil Areas.
- Author
-
Meng, Fei and Peng, Yipu
- Subjects
GROUTING ,GROUT (Mortar) ,ENGINEERING design ,FINITE element method ,CEMENT mixing - Abstract
In soft soil areas, to compare the load-bearing characteristics of bag grouting piles and cement mixing piles and study the load-bearing mechanism of bag grouting piles, field tests are conducted in this study, including the comparative compressive test of bag grouting piles and cement mixing piles, and the analysis of pile axial force, pile side friction resistance, and pile end resistance. Moreover, a numerical simulation is developed using ABAQUS 2020 (finite element analysis software) for three-dimensional modeling. The numerical simulation results are compared with the field test results to verify the reliability of the numerical simulation. Furthermore, the influences of five factors are studied; namely, pile length, pile diameter, pile spacing, the thickness of the bedding layer, and grouting pressure are studied for their effects on the compressive bearing characteristics of the bag grouting pile. The results show the following: (1) For composite foundations, bag grouting piles are more effective than cement mixing piles in soft soil areas, and the former provide an 8.8% increase in the bearing characteristics. (2) With an increase in the load, the bag grouting pile experiences greater compression in the middle of the pile body, and the pile side friction resistance is increased; therefore, the pile side friction resistance can be fully developed, and the bag grouting piles have the ability to transfer the load from the top of the pile to the soil at the bottom of the pile. (3) When the external load is maximized, the sharing ratio of pile side friction resistance reaches 96.3%, which shows the excellent frictional performance of bag grouting piles. (4) Among the five factors mentioned above, the most important one is the pile diameter, followed by the pile length and pile spacing, the thickness of the bedding layer, and finally the grouting pressure. The optimal combination in this paper is a pile length of 18 m, pile diameter of 0.4 m, pile spacing of 1.0 m, bedding thickness of 0.3 m, and grouting pressure of 0.6 MPa. Therefore, changing the pile diameter can be given priority during the construction design. The findings in this paper can provide valuable insights and practical experience for the design of similar engineering projects. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Experimental and numerical investigations of CFRP reinforced masonry beams performance under bending loads.
- Author
-
Zaghlal, Mahmoud, El-Sisi, Alaa, Husain, Mohamed, and Samy, Samar
- Subjects
- *
SHEAR reinforcements , *MASONRY , *CARBON fiber-reinforced plastics , *MORTAR , *GROUT (Mortar) , *MATERIALS testing - Abstract
In this paper, an experimental and numerical study was achieved to investigate the behavior of masonry beams internally reinforced using carbon fiber-reinforced polymer (CFRP) and hybrid steel/CFRP reinforcements. Three beams were built using concrete bricks and grout mortar. The brick was designed with two holes that were filled with grout before placing the rebar inside. One beam was built without shear reinforcement, and the other two were with shear reinforcement. Material characterization tests were performed to evaluate the compressive strength of the brick and the masonry cube and the flexural strength of the masonry prism. The masonry cubes were prepared and tested to evaluate their equivalent mechanical properties. The beams were tested in three-point bending with an effective simply supported span of 840 mm where the load deformations and failure loads were monitored. Finite element models were built using ANSYS and validated with experimental results. Additional beam models were analyzed to study the effect of shear reinforcement spacing from 0.78d to 0.39d and more hybrid reinforcement configurations. Results showed that using equivalent material properties in numerical modeling instead of modeling bricks and mortar was acceptable. In addition, using shear reinforcement with a spacing of 0.78 d didn't enhance the shear behavior of the spacing. Finally, the hybrid steel/CFRP-reinforced beam with shear reinforcement achieved the highest capacity compared to the two other beams. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Experimental Research on Application of Waste Concrete Powder–Waste Brick Powder–Cement Grout for Foundation Reinforcement in Mining Goaf.
- Author
-
Wang, Yan, Wang, Mengqi, Wang, Hui, Dun, Zhilin, and Ren, Lianwei
- Subjects
- *
CONCRETE waste , *CONSTRUCTION & demolition debris , *GROUT (Mortar) , *BRICKS , *GROUTING , *SCANNING electron microscopy , *FLY ash - Abstract
Combined with a strategic policy for the recycling of construction waste, this paper puts forward a programme for treating a goaf foundation with waste concrete powder, waste brick powder, and cement grout (BCP cement grout). The BCP cement grout is prepared by replacing part of the waste concrete powder with waste brick powder, and the changeable rule of the setting time, water separation rate, stone rate, and viscosity of the grout with different rates for replacement are studied. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are carried out. The mineral composition is analyzed and the microscopic mechanism is studied. The results show that the ratio of BCP cement grout developed by the experiment is reasonable; the unit cost is less than 160 yuan/t, which is 40% lower than that of pure cement grout; and both a good economic effect and good environmental effect are obtained. It has the advantages of low water separation rate, high stone rate, and low viscosity. When the ratio of cement powder: waste concrete powder: waste brick powder is 3:5:2 or 3:6:1, the 28 d compressive strength of the stone body is more than 2 MPa, meeting the filling requirements for a goaf foundation. It is not only technically feasible but also economically reasonable to apply construction waste powder to fill the goaf foundation. Recycling and utilizing construction waste can also achieve the ecological restoration of mined-out areas, highlighting the ecological benefits. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
39. Sewing Concrete Device—Combining In-Line Rheology Control and Reinforcement System for 3D Concrete Printing.
- Author
-
Jacquet, Yohan and Perrot, Arnaud
- Subjects
- *
THREE-dimensional printing , *SEWING , *GROUT (Mortar) , *RHEOLOGY , *STEPPING motors - Abstract
Of the digital concrete-additive-manufacturing techniques, extrusion-based systems are probably the most widespread and studied. Despite the significant potential offered by 3D printing, several challenges must still be overcome. For instance, although several solutions have already been explored, the automated reinforcement of the layer-wise printed structures represents a challenge. The inline quality control of the fresh-state properties of 3D-printed materials is also an open question that needs to be addressed to find an efficient shared practice. This study proposes a new device designed to simultaneously reinforce 3D-printed structures along and through the layers and to be used as an inline quality-control device. This device consists in a sewing system, which is composed of a rotating system, and a hollow needle, which drives a reinforcing cable or yarn and can be used to inject cement grout to fill holes and improve bonding with reinforcement. The rotation is induced by a stepper motor, which measures the torque that is required to make the needle penetrate. This measurement can be used as a quality-control index to ensure material homogeneity. This paper aims to present an original reinforcement system that can be fully automated and simultaneously create reinforcement patterns in different directions of the printed structure while controlling the material's fresh properties. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
40. Characteristics and application of new grouting materials for poor geology with rich water.
- Author
-
Yuanli Bai and Chao Tao
- Subjects
- *
GROUTING , *FLY ash , *GROUT (Mortar) , *MECHANICAL behavior of materials , *GEOLOGY , *COAGULATION , *SLURRY - Abstract
The poor water-rich geology in underground engineering construction is easy to cause geological disasters such as water inrush, sand gusher, and sand flow, which have adverse effects on engineering progress and personnel safety. Grouting is an effective means to control poor geology with rich water, but the traditional cement grouting material has some issues such as long coagulation time and low strength. Therefore, this study proposed a new grouting material based on graphene oxide and fly ash. Through the systematic analysis of the material, the working performance of the material was verified. Considering the fluidity, stability, setting time, and economy of the slurry, 0.03% graphene oxide and 20% fly ash were mixed into the slurry, which not only ensured the excellent properties of the slurry, but also realized the resource of fly ash. The mechanical property analysis of the material indicated that, when the fly ash content was 10%, the flexural strength increased by 8.11% and the compressive strength increased by 6.01% at the age of 28 days. When the fly ash content was 20%, the flexural strength was improved by 4.39%. The compressive was enhanced by 8.13%. The experimental results verified the feasibility of the grouting material. A low carbon, green, and high-performance grouting material is very important for the treatment of water-rich crushing zones. This study provided a new solution for the grouting reinforcement project of water-rich fracture zone, which owned the essential research significance and values. [ABSTRACT FROM AUTHOR]
- Published
- 2023
41. Numerical Simulation Study on Influence of a Structural Parameter of D Bolt, an Energy-Absorbing Rock Bolt, on its Stress Distribution.
- Author
-
Pyon, Kwang Nam, Son, Kyong Su, and Han, Un Chol
- Subjects
ROCK bolts ,STRESS concentration ,FINITE difference method ,GROUT (Mortar) ,COMPUTER simulation - Abstract
A D bolt, an energy-absorbing rock bolt, is a smooth steel bar with a number of anchors along its length. The anchors, which can be spaced evenly or unevenly along its length, are firmly fixed within a borehole using either cement grout or resin, while the smooth sections of the bolt between the anchors may freely deform in response to rock dilation. A series of numerical simulations have been conducted using the finite difference method to investigate the effects of D bolt on the displacement increase of rock mass around a roadway in comparison with normal fully encapsulated rebar. As a result, the displacement of 49 mm at the top of roadway roof in the D bolts supported model is much larger than 30.08 mm in the fully encapsulated rebar bolts supported model so that the former is capable of absorbing potential deformation energy of rock mass around a roadway to tolerate the large deformation of rock. Plans of spacing arrangement of D bolt's anchor have a significant effect on stress redistribution of the bolt. The numerical simulation result shows that for the D bolt with its whole length of 2.4 m, the length of its exposed section of 0.1 m, and the 4 anchors with the length of 0.1 m, the maximum tensile stress of 3.25 GPa generated in the D bolt with the ratio of the spacing between anchors (RSA) of 30 : 40 : 50 : 70 is lower about 1.13–1.31 times than the other D bolts with different ratio of spacing, and the changing range of stress is also the smallest, where the ratio of 30 : 40 : 50 : 70 indicates a ratio of lengths of deformable sections which is determined by turns from the innermost section of rock mass around roadway to the outermost section of roadway space. This study demonstrates that it is reasonable to employ the RSA of D bolt which makes it bring out its energy-absorbing capability to the full. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
42. 不良地质段双护盾 TBM 施工综合处理技术.
- Author
-
杨继华, 闫长斌, 齐三红, 郭卫新, and 杨风威
- Subjects
- *
WATER tunnels , *GROUT (Mortar) , *FAULT zones , *ROCK analysis , *DRAINAGE , *TUNNEL design & construction - Abstract
Aiming at the poor geological conditions of water conveyance tunnel in Lanzhou water source construction engineering by double shield TBM excavation, the comprehensive methods and treatments were put forward by data statistics, engineering analogies, and other methods. Before TBM tunneling, F, fault zone and F, fault zone were excavated by drilling and blasting method. After initial support which guaranteed the stability of surrounding rock, TBM slided through and installed segments. Based on geological analysis along tunnel, combination the observation of tunneling face, rock muck analysis and tunneling parameter analysis, the geological conditions of surrounding rock in front of tunneling face were comprehensively predicted by using three-dimension seismic method and three-dimensional resistivity method. The principle of " drainage first, drainage and plugging combined" was adopted, the variable slope drainage system was established, the operation mode of the drainage system was determined according to the amount of water gushing. According to the characteristics of the front shield blocked, the method of releasing surrounding rock pressure by manual excavation of the heading tunnel from the telescopic shield was adopted to make the TBM out of blocked. Based on identifying geological conditions, the use of chemical grouting and cement grouting consolidation broken surrounding rock, controlling TBM tunneling parameters, slow tunneling through the fracture zone. TBM tunnneling practice shows that the adopted technology is effective and the poor geological conditions have not caused serious consequences for TBM. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
43. Treated Waste Tire Using Cement Coating as Coarse Aggregate in the Production of Sustainable Green Concrete.
- Author
-
Paul, Suvash Chandra, Islam, Shamsul, Mamun, Abdullah Al, Islam, Naymul, Babafemi, Adewumi John, Kong, Sih Ying, and Miah, Md Jihad
- Subjects
- *
TIRE recycling , *SUSTAINABILITY , *WASTE tires , *RUBBER waste , *WASTE products , *RUBBER , *CONCRETE waste , *GROUT (Mortar) - Abstract
Waste tire rubber is one of the most concerning environmental pollution issues. With the increasing demand for automobile production, the rate of waste tire generation has also increased. However, these tires often end up stockpiled and not properly disposed of. This non-biodegradable waste poses severe fire, environmental, and health risks. Due to the progressively severe environmental problems caused by the disposal of waste tires, the feasibility of using such elastic waste materials as an alternative to natural aggregates has become a research topic. The main objective of this research is to investigate the changes in the mechanical and durability properties of concrete with the inclusion of waste tire rubber at specific contents. A total of 80 cylinders measuring 100 mm × 200 mm were cast with waste tire aggregate as a partial replacement for natural coarse aggregate (5% and 10% by weight of natural coarse aggregate). A surface treatment of tire aggregate using a cement coating was performed to study its effect on concrete properties. This research indicates a noticeable reduction in the compressive and split tensile strength of concrete containing untreated waste tire rubber compared to normal concrete made with natural aggregates. However, an improvement was observed when the surface of tire aggregates was coated with cement grout. Additionally, it was noted that the slump value, water absorption, and porosity increased as the percentage of rubber increased. Nevertheless, unlike normal concrete, the failure pattern in tire-mixed concrete occurs gently and uniformly, indicating ductile behavior. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
44. A RESIN TYPE ADDITIVE USE TO IMPROVE LOAD BEARING CAPACITIES OF GROUTED ROCK BOLTS EXPOSED TO THERMAL CYCLES.
- Author
-
KÖMÜRLÜ, Eren
- Subjects
ROCK bolts ,THERMOCYCLING ,GROUT (Mortar) ,CEMENT mixing ,ADDITIVES - Abstract
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- 2023
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45. Fracture Behavior of Semiflexible Pavement Containing Cement Asphalt Emulsion Paste.
- Author
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Zarei, Sohrab, Ouyang, Jian, Alae, Mohsen, and Zhao, Yanqing
- Subjects
- *
DIGITAL image correlation , *ASPHALT , *CEMENT , *GROUT (Mortar) , *EMULSIONS , *PAVEMENTS - Abstract
Semiflexible pavement (SFP) is gradually gaining more attention for its excellent rutting resistance and high load-bearing capacity. However, cracking damage is one of the most challenging distresses in SFP due to the brittle behavior of cement paste (CP) and insufficient adhesion between porous asphalt matrix (PAM) and hardened CP. In this study, the cement asphalt emulsion paste (CAEP) was introduced as a grouting material for SFP to overcome the shortcomings of CP. Therefore, the effect of CAEP on the cracking resistance of the SFP was studied by conducting a semicircular bending test and obtaining the full-field displacement and strain of the specimen during the whole loading process through digital image correlation (DIC). The maximum average value of full-field tensile strain was proposed to accurately determine the specimens' fracture failure point for calculating fracture parameters. Results indicated that DIC data could identify the three fracture phases of SFP materials (i.e., crack initiation, crack propagation, and failure) precisely. In addition, incorporating the asphalt emulsion in the cement grout significantly improved the SFP material's fracture performance by increasing the fracture energy, J-integral (Jc), and cracking resistance index (CRI) values on average by 48%, 76.1%, and 43% in SFP with CAEP20 and by 13.4%, 45.7%, and 87% in SFP with CAEP40, respectively. Overall, CAEP with an asphalt emulsion content between 20% and 40% by weight of cement is recommended as the best grout in SFP to obtain the best cracking resistance. [ABSTRACT FROM AUTHOR]
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- 2023
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46. Behavior of high-strength demountable bolted shear connectors in steel-concrete girders with prefabricated slabs.
- Author
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Shamel Fahmy, Ahmed, Mostafa Swelem, Sherine, and Kamal Abdelaziz, Mohamed
- Subjects
GIRDERS ,CONCRETE slabs ,GROUT (Mortar) ,CONSTRUCTION slabs ,COMPOSITE structures ,FINITE element method ,COMPOSITE construction - Abstract
Composite structures with prefabricated concrete slabs and bolted shear studs can enhance the effectiveness and sustainability of construction. In this research, non-shrinkage cement grout is proposed to be filled between high-strength fully threaded bolt shear connectors and a prefabricated slab. Six static push-out tests are performed with different bolt dimensions and different pretension forces on the bolts to study the behavior of bolted shear studs. Finite element models for bolted shear connectors using ABAQUS/Explicit solver are developed, and they matched well with experimental results. Moreover, a Parametric study is conducted to investigate the effects of grout strength, bolt diameter, length-to-diameter ratio, bolt preloading, and bolt material type on the performance of shear connectors. Finally, the results of the parametric analysis are compared to the current design codes and previous researches and more precise equations for predicting the capacity and stiffness of bolted shear studs are proposed. [ABSTRACT FROM AUTHOR]
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- 2023
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47. Investigation of the deterioration mechanisms induced by moisture and soluble salts in the necropolis of Porta Nocera, Pompeii (Italy).
- Author
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Kilian, Ralf, Borgatta, Léo, and Wendler, Eberhard
- Subjects
- *
TOMBS , *SOLUBLE salts , *SURFACE hardening , *ANCIENT cemeteries , *GROUT (Mortar) ,POMPEII - Abstract
This paper focuses on the diagnosis of damage processes of decorative Roman renders of a group of tombs in the Porta Nocera necropolis in the ancient city of Pompeii, Italy. Unprotected from various climatic events, the tombs keep on deteriorating since they were first excavated in 1954. Extensive on-site and laboratory diagnostics using non-destructive and low-destructive techniques have been able to demonstrate that soluble salts are among the major agents of deterioration, causing damage in the form of render delamination. Gypsum is formed on the surface of the materials by the deposition of sulfur dioxide, resulting in reduced porosity and hardening of the surface. Soluble salts of nitrates and chlorides that penetrate the tombs' masonry from the ground and are transported through the render layers tend to crystallize in subsurface. The crystallization—dilution cycles of the soluble salts cause major mechanical pressures, leading to the progressive destruction of the renders. Past conservation strategies to secure plasters have shown only limited effectiveness. In light of the data collected regarding salt decay, the authors propose new strategies, questioning the systematic use of grouts and restoration mortars for conservation treatments and focusing on preventive conservation and maintenance to ensure the long-term preservation of masonry and decorative surfaces of the tombs. [ABSTRACT FROM AUTHOR]
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- 2023
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48. Utilization of High-Volume Red Mud Application in Cement Based Grouting Material: Effects on Mechanical Properties at Different Activation Modes.
- Author
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Gao, Yifan, Li, Zhaofeng, Xin, Gongfeng, Shen, Quanjun, Zhang, Jian, and Yang, Yaohui
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MECHANICAL behavior of materials , *GROUT (Mortar) , *MUD , *HEAT of hydration , *SCANNING electron microscopes , *CEMENT - Abstract
The high alkalinity and storage of red mud (RM) make it a major environmental problem. In this paper, the mineral composition, hydration process, and microstructure of red mud-cement based grouting materials (RCGM) are studied by means of the differential thermal analyzer, X-ray diffraction (XRD) diffractometer, isothermal calorimeter, and scanning electron microscope. The action mechanism of RM after thermal activation (TRM) and mechanical activation (SRM) on the mechanical properties of RCGM is summarized, respectively. The results show that a small amount of RM, SRM, and TRM can improve the early strength of RCGM, and the effect of TRM is the best. The RM will reduce the late strength of sample. The SRM and TRM still promote the strength of sample, and the compressive strength of SRM-80 and TRM-80 meet the requirements of grouting engineering. The RM, SRM, and TRM don't change the hydrate phase of RCGM, and hematite and nepheline mainly play a filling role in the material system. A small amount of RM, SRM, and TRM can promote the hydration process of ordinary portland cement (PC), whereas excessive RM, SRM, and TRM can delay the hydration process of PC. Before hydration heat release for 15 h, the RM, SRM, and TRM can accelerate the reaction rate in the early stage of hydration induction, which is independent of activation mode and dosage on RM. Among them, SRM-20 and TRM-20 have the best effect on promoting hydration. The microstructure analysis shows that RM, SRM, and TRM mainly improve the mechanical properties of RCGM through the microfilling. Mechanical activation and thermal activation can improve the activity of RM, and the effect of TRM is more obvious. [ABSTRACT FROM AUTHOR]
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- 2023
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49. Parameter Optimization of Constant Pressure Grouting Technology for Borehole Sealing with Inorganic Noncondensable Material in Tectonic Coalbed of South China.
- Author
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Pengtao, Zhao, Haiqiao, Wang, Long, Wang, Xinlei, Wang, and Hongyu, Ma
- Subjects
- *
GROUTING , *SEALING (Technology) , *DRAINAGE , *GROUT (Mortar) , *MATERIALS testing , *STRESS concentration , *SLURRY - Abstract
To solve the problem of a rapid attenuation of gas concentration along with drainage borehole collapse in the tectonic coalbeds of South China, a constant pressure grouting technology with inorganic, noncondensable material was proposed. Firstly, the slurry fluidity, water separation rate, and sealing performance of the inorganic sealing materials were tested under different water-cement ratios. The seepage model of slurry in a layer-through borehole was built with COMSOL Multiphysics simulation software, to explore the scopes of loose circles around drainage roadway and borehole, and to analyze the seepage capacity of the slurry under different grouting pressures. Eventually, the sealing performance of the slurry was investigated in the field. The results showed that the inorganic, noncondensable material with the water-cement ratio of 5 : 1 has a strong fluidity, low water retention, high permeability, and good sealing performance. After the excavations of No.2164 drainage roadway and layer-through borehole, there are obvious stress concentrations both at the shoulder corners of the roadway and at the borehole bottom, and the scope of the loose circle around the roadway is about 6.2 m. The effective seepage radius of the inorganic slurry gradually increases with a rising grouting pressure, and the slurry seepage range in the sandstone section is broader than that in the mudstone section. Adopting the constant pressure grouting technology with the slurry, the average drainage concentration of boreholes in Puxi coal mine is 51.5%, and the average gas flow rate is 0.005 m3/min, which are 1.35 times and 1.67 times than those with the cement grouting method. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
50. Cement grouting online monitoring and intelligent control for dam foundations.
- Author
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Qixiang Fan, Xiaochun Jiang, Kexiang Wang, Canxin Huang, Guo Li, and Pengcheng Wei
- Subjects
INTELLIGENT control systems ,GROUT (Mortar) ,GROUTING ,ROBUST control ,CLOUD computing - Abstract
This paper shares the experience of China Three Gorges Corporation in intelligent grouting management for dam foundation reinforcement. An intelligent grouting control system called intelligent grout control hub with intelligent management (iGHM) was introduced to realize one-button closed-loop intelligent control of cement grouting by its robust grouting control models, novel grouting facilities, and intelligent online monitoring approaches. In this system, the grouting period (t) is intelligently divided into three zones and five phases based on the product of grouting pressure (P) and unit grouting rate (Q), which provide quantitative criteria for the grouting process control. Innovative grouting facilities (e.g., intelligent non-grading slurry tank, intelligent pressure control system, and central hub for grouting data management) and an intelligent grouting management cloud platform are subsequently incorporated to monitor, analyze, and evaluate grouting data online for efficient digital grouting management. Its application of consolidation grouting and high-pressure curtain grouting at the Baihetan Hydropower Station demonstrates that this intelligent grouting system could improve grouting quality with promising applications in similar projects. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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