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This study examined the mechanical behavior characteristics of cold recycled emulsified asphalt bases with RAP 76% and emulsified asphalt 3%, in different cure time, i.e., 0, 7, 14 and 28 days and evaluated in terms of the resilient modulus (RM) and permanent deformation (PD) based on repeated load triaxial tests. The results demonstrated that in the first 7 days, the RM increased by 80% compared to the freshly compacted material and after this period, the subsequent increases were not as significant, ranging, from 10.9% to 19.4%, that shows that initical cure time significantly influences the RM behavior of the mixtures. However, the mixtures showed considerable permanent deformations, even after 28 days of curing. This indicates that the use of asphalt emulsion, with prolonged curing, improves the mechanical properties of the mixture but does not entirely resolve the issue of permanent deformation in cold reclaimed asphalt mixture (CRAM). The plastic deformation behavior observed in the triaxial tests must be taken into account when designing pavements containing RAP and asphalt emulsion. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of curing time on the edible quality and oxidative characteristics of compound low-sodium yak meat products, in this experiment, complex low-sodium yak meat was selected to investigate the effects of curing time (12, 18, 24, 30 and 36 h) on the edible quality and oxidative characteristics. The results showed that prolonging the curing time significantly reduced the cooking loss (P

This study investigates the efficacy of sodium alginate (SA), xanthan gum (XG), guar gum (GG) and chitosan (CS) — each applied at five different solid biopolymer-to-water mass ratios (or dosages) and cured for 7 d and 28 d — on the unconfined compressive strength (UCS) performance of a high plasticity clayey soil. Moreover, on identifying the optimum biopolymer-treatment scenarios, their performance was compared against conventional stabilization using hydrated lime. For a given curing time, the UCS for all biopolymers followed a rise–fall trend with increasing biopolymer dosage, peaking at an optimum dosage and then subsequently decreasing, such that all biopolymer-stabilized samples mobilized higher UCS values compared to the unamended soil. The optimum dosage was found to be 1.5% for SA, XG and CS, while a notably lower dosage of 0.5% was deemed optimum for GG. Similarly, for a given biopolymer type and dosage, increasing the curing time from 7 d to 28 d further enhanced the UCS, with the achieved improvements being generally more pronounced for XG- and CS-treated cases. None of the investigated biopolymers was able to produce UCS improvements equivalent to those obtained by the 28-d soil–lime samples; however, the optimum XG, GG and CS dosages, particularly after 28 d of curing, were easily able to replicate 7-d lime stabilization outcomes achieved with as high as twice the soil's lime demand. Finally, the fundamental principles of clay chemistry, in conjunction with the soil mechanics framework, were employed to identify and discuss the clay–biopolymer stabilization mechanisms.

Early-age masonry structures require temporary support until they achieve full strength. Nevertheless, there is a limited understanding of the properties of freshly laid masonry and the design of newly constructed, unsupported masonry walls. This situation has led to numerous instances of structural damage and injuries to workers, prompting conservative construction bracing techniques. This paper presents comprehensive experimental studies on early-age mortar cubes and masonry prisms to assess the effects of curing time on the compressive properties of masonry assemblies, which is necessary for the design of temporary bracing. The change in modulus of elasticity and compressive strength of masonry prisms and mortar with curing time has been experimentally assessed. The results indicate that the compressive strength of freshly cast mortar cubes is relatively insignificant until approximately 24 h after construction, when it was observed to increase logarithmically. Regarding the performance perspective, the compressive strength of early-age masonry prisms is inconsiderable, less than 15% of full strength during the first day after construction. By contrast, regarding the life safety perspective, the compressive properties of a mortar joint within a masonry assembly (which is of more practical interest) appear to have no effect on the failure strength of concrete masonry prisms over the range of ages tested. The failure modes of the early-age mortar cubes and early-age masonry prism samples depend on the curing time, and different failure modes occurred before and after the start of the primary hydration phase, which is 20.8 h after construction. It is anticipated that the proposed research will provide valuable material properties leading to efficient design of control devices (e.g., temporary bracing) and improved guidelines for concrete-block masonry construction. [ABSTRACT FROM AUTHOR]

On the 2nd runway of Shanghai Pudong International Airport, the field assessment was conducted for rigid pavement stabilization using cementitious grout. The support performance of underlying layers and voids beneath slabs were considered, and the deflection testing was performed before and after grouting. The performance of pre-treatment and post-treatment pavements, and effects of injecting depth and curing time on grouting treatment were statistically analyzed. Results indicated that the support performance of underlying layers along the wheelpath was gradually getting deteriorated and non-uniform during the service period, and the number of voids beneath slabs would also increase annually. The injecting depth at 10 cm under subbase layer was proposed for rigid pavements with the crushed stone subbase layer. Besides, the performance evaluation of cementitious grouting stabilization for rigid pavement was recommended after 60-day curing. Finally, results demonstrated that the objective of pavement stabilization for the 2nd runway was successfully achieved. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office 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.)

This study investigated the strength behaviors of dredged clays treated with metakaolin (MK) and fly ash (FA). A series of laboratory tests including direct shear and unconfined compressive strength tests were performed on MK and FA-treated dredged clay at various MK contents and different curing times. The direct shear test results showed that the shear stress and displacement curves for all specimens tested are strain-softening types and influenced by MK content and curing time. The variation curve at a higher MK content or higher curing time is always higher than that at a lower one. The shear strength from the direct shear test at a given vertical stress consistently increases linearly with the increase of MK content while increasing parabolically with curing time. This indicates both curing time and MK content contribute to the development of the shear strength. Both strength parameters c and φ grow with increasing MK content and curing time. Unconfined compressive strength test results show the strain-softening behavior for all tested specimens. Compared with adding FA alone or MK alone, adding both fly ash and MK exhibited a better treatment effect in the unconfined compressive strength, which increases with increasing MK content and curing time. [ABSTRACT FROM AUTHOR]

This study examines the combined impact of pre-test curing and soaking periods on the soil's resistance to collapse those results from treating gypseous sand with varying amounts of nanoclay. The soil comes from the Iraqi city of Najaf. The soil sample is mainly sand. The nanoclay named "Montmorillonite K10" is used, and it is non-toxic. The tests are performed with a computerized Oedometer. The collapse potential is estimated according to a single Oedometer test (SOT), where the specimens are initially dry and then soaked under a stress level of 200 kPa. Four data sets related to the percentages of 0, 3, 6, and 12% nanoclay are used. Each data set comprises three groups of pre-tests for curing duration and different soaking durations. All experiments have a constant initial dry density of 1.64 g/cm3, water moisture of 3%, and gypsum content of 29%. The findings of this study show that the collapse potential (CP) of natural soil specimens decreases as the pre-test curing time increases. Generally, there is a decrease in CP due to adding the nanoclay and 6% of the nanoclay exhibited the highest reduction in CP. Also, there is an increase in the pre-test curing for the nanoclay-treated soil specimens, which leads to an increase in the CP related to the no-curing state. [ABSTRACT FROM AUTHOR]

Background and Objectives: In the Hyrcanian forests, the presence of fine-grained clayey soils presents considerable challenges for construction endeavors, particularly road building projects. These soils exhibit a propensity to swell, leading to instability in road surfaces and consequent pavement degradation. The adverse technical attributes of fine-grained soils, encompassing factors such as plasticity, low permeability, weak strength, fluctuations in pore water pressure, volumetric alterations, textural nuances, chemical composition, and grain structure, engender intricate engineering complexities. Soil stabilization emerges as a pivotal solution to ameliorate the swelling tendencies inherent in such soils. This process entails the incorporation of natural or synthetic additives to bolster the mechanical characteristics of the soil. Cost-effective and easily accessible materials like lime and plant waste serve as practical agents for soil stabilization, offering a sustainable approach to enhancing soil properties and mitigating the challenges posed by fine-grained clayey soils in construction projects within the Hyrcanian forests. Materials and Methods: This study focused on enhancing roadbed soil properties within the educational and research Forest of Sari University of Agricultural Sciences and Natural Resources - Darabkala. A fixed 3% hydrated lime content, along with varying proportions of reed plant ash derived from Phragmites australis (3%, 6%, 9%, and 12%), was incorporated into the soil. Subsequent to this soil treatment, a series of comprehensive soil mechanics tests were carried out, including Atterberg limits assessment, standard compaction tests, California Bearing Ratio (CBR) evaluations, and uniaxial compressive strength (UCS) tests. These tests were conducted in triplicate following the processing period to evaluate the impact of the additives on the mechanical properties of the roadbed soil. Results: The findings demonstrate a reduction in the liquid limit and plasticity index, alongside an increase in the plastic limit of the soil following the addition of reed ash. The maximum dry unit weight of the samples exhibited a decrease with the incorporation of reed ash, ranging from 14.52 kN/m³ as the highest to 11.97 kN/m³ as the lowest in the sample containing 3% lime and 12% reed ash. Values of the CBR test displayed a progressive increase from 4.9% to 9.7% in the soil sample containing 3% lime and 12% reed ash. The results of the uniaxial compressive strength tests conducted over three durations (7, 14, and 28 days) indicate that the highest compressive strength of 2.6 kg/cm² was achieved in the sample with 3% lime and 6% reed ash after 28 days. Conclusion: The study concludes that reed ash serves as an effective pozzolanic material for stabilizing forest road subsoils in the research area. Optimal stabilization of the clay subsoil was achieved with a mixture comprising 3% lime and 6% reed ash, applied over a period of 28 days. This blend proved to be instrumental in enhancing the mechanical properties of the roadbed soil, suggesting its viability for sustainable road construction practices in similar environments. [ABSTRACT FROM AUTHOR]

Protecting stone on facades or exterior art works from deterioration is primarily about protecting them from rainwater. Hydrophobic coatings are widely used for this purpose. Here, two factors affecting the long-term efficiency of some coatings applied on stones were investigated: the number of coating layers and the curing time after their application. Tests of water absorption by capillarity, absorption at total immersion in water, and a visual check of the penetration depth have been carried out. The coating's efficiency coefficient Cef was defined as the ratio of the maximum water absorption of a treated sample to an untreated one. Two commercial silicon-based coatings were applied on the highly porous Hořice sandstone alternatively. Curing times of 2 days vs. 2 weeks, and 2 coating layers vs. 3 layers were compared. The experiments showed that the coating's efficiency is affected more by the curing time than by the number of applied coating layers. The curing time of 2 days after coating's application is too short, but 2 weeks proved to be sufficient for both tested coatings. There was no big difference regarding the number of coating layers; two layers seem to be sufficient if a long rain-free curing time can be guaranteed. [ABSTRACT FROM AUTHOR]

Soil–cement mixtures have practical applications in geotechnical engineering. Peculiarities associated with the stiffness and strength gains over the curing time provided by cementation need to be investigated, especially for tropical soils. Few studies investigated mixtures of tropical soils and high early strength Portland cement, in order to understand the changes in physical and mechanical properties associated with mineralogical and microstructural alterations caused by artificial cementation. This work aimed to study the effects of cementation on a tropical clay soil using ultrasonic method and to correlate the results with those of other tests. The ultrasonic pulse velocity (UPV) was evaluated for the natural soil and mixtures of soil with different cement contents (1%, 2%, 3%, 5%, 7%), after different curing times, based on propagation of longitudinal ultrasonic waves. Mineralogical and microstructural analyses, geotechnical characterization, resilient modulus (RM) and unconfined compressive strength (UCS) tests, and physical–chemical investigation through volumetric variation were also developed. The ultrasonic response revealed direct effects of cementation on micromorphology, plasticity and granulometry. A microstructure with larger pores was transformed into a dense structure with particles bonded by cementitious compounds. This change provided new paths for the propagation of ultrasonic waves (UPV increases exceeded fourfold for a cement content of 7%) and greater mechanical resistance to the application of cyclic and static loads. Nearly linear increases in UPV, UCS and RM were observed with the addition of cement. A good linear relationship was observed between the values of UPV and RM (R2 > 0.8968) or UCS (R2 > 0.8925). [ABSTRACT FROM AUTHOR]

Light-cured composite resins are widely used in dental restorations to fill cavities and fabricate temporary crowns. After curing, the residual monomer is a known to be cytotoxic, but increasing the curing time should improve biocompatibility. However, a biologically optimized cure time has not been determined through systematic experimentation. The objective of this study was to examine the behavior and function of human gingival fibroblasts cultured with flowable and bulk-fill composites cured for different periods of time, while considering the physical location of the cells with regard to the materials. Biological effects were separately evaluated for cells in direct contact with, and in close proximity to, the two composite materials. Curing time varied from the recommended 20 s to 40, 60, and 80 s. Pre-cured, milled-acrylic resin was used as a control. No cell survived and attached to or around the flowable composite, regardless of curing time. Some cells survived and attached close to (but not on) the bulk-fill composite, with survival increasing with a longer curing time, albeit to

Copyright of Journal of Ground Improvement is the property of Journal of Ground Improvement Editorial Office 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.)

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office 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.)

In order to investigate the curing time of different curing agents used in casting polymer bonded explosives, Fourier transform infrared spectrometer, rotary rheometer and Shore A hardness tester were used to investigate the effects of toluene diisocyanate (TDI), dimeric acid diisocyanate (DDI) and TDI/ DDI mixed curing agent on curing rate, pot life and curing time of pouring PBX slurry. The results show that the reaction rate of HTPB with different curing agents at 55 ℃ is kTDI > kTDI/ DDI > kDDI, and the reaction follows the second-order reaction rule. For cast PBX slurry with high solid content, at a curing ratio of 1. 2 and curing temperature of 55 ℃, using TDI curing agent, suitable pot life was 4 hours, curing time was 72 hours; Using DDI curing agent, pot life can reach more than 5 hours, but its curing time was 128 hours. Using TDI/ DDI mixed curing agent, curing time is 96 hours, pot life can reach more than 5 hours, curing effect is more ideal. [ABSTRACT FROM AUTHOR]

Chilean mining faces challenges associated with the depletion of oxidized copper ore and the environmental complexity of treating concentrates with high arsenic content. Given this, hydrometallurgy emerges as an alternative for the treatment of these concentrates. This research analyzes the interaction of sulfuric acid (0, 70, 140, and 210 kg/t), sodium chloride (0, 25, 50, and 100 kg/t), curing time (1, 5, 10, and 15 days), and temperature (25, 35, 50, and 75 °C) in the pretreatment of a copper concentrate with 35.57% total copper and 5.91% arsenic (enargite, 35.93%). In the pretreatment, a maximum copper extraction of 26.71% is achieved using 210 kg/t sulfuric acid at 50 °C over 15 days of curing. The experimental results are analyzed through an empirical model, where the interaction between sulfuric acid and curing time is identified as beneficial when the sulfuric acid addition is above 70 kg/t, leading to higher moisture content in the sample. In the absence of sulfuric acid, sodium chloride significantly influences the achievement of higher copper extractions. During curing at higher temperatures, the importance of maintaining a moisture level is emphasized to prevent solution evaporation and hinder diffusion through the particles, thereby ensuring reactivity in the sample. [ABSTRACT FROM AUTHOR]

The unique physical and chemical properties of silica fume enhance the compressive strength and water resistance of cement mortar. The study aims to investigate the effect of silica fume in cement mixes in terms of strength-gaining characteristics and water-resistance attributes. The silica fume was added in amounts of 0%, 10%, 20%, and 25% as a partial cement replacement for the production of mortar. A total of 120 mortar cubes were prepared with steel molds of 50 × 50 × 50 mm dimensions. Two water-cement ratios (w/c) of 0.4 and 0.5 were utilized to investigate the water-resistance properties. A water-resistant property was calculated using the compressive strength ratio in the saturated surface dry (SSD) state to the oven-dry condition. The compressive strength ratios in SSD and the oven-dry state were measured after curing in water for 3, 7, 28, 45, and 90 days. After 90 days of curing, the sample with a water-cement ratio of 0.4 exhibited the greatest compressive strength and the highest ratio of SSD to the oven-dry state. The higher SSD to oven-dry strength ratio shows the silica fume possesses superior water resistance. This study concludes that silica fume possesses great pozzolanic activity and excellent resistance to water. The incorporation of silica fume creates a concrete composition that enables the construction of durable concrete structures. [ABSTRACT FROM AUTHOR]

Cement-stabilization of weak and soft soils is an efficient way for ground improvement. Traditional Portland cement remains the most popular cementitious material in practice, and thus, a proper dosage design of cement-stabilized soil is of practical interest to meet the sustainable engineering requirements and to remedy environmental concerns. Based on the unconfined compression test of cement-stabilized Qiantang River silty clay, the effects of cement content, mixing moisture content, mixing-water-to-cement ratio, and curing time on the unconfined compressive strength were investigated. The results show that the mixing-water-to-cement ratio can comprehensively characterize the effects of cement content and water content on the unconfined compressive strength of the cement-stabilized clay. A prediction method for the unconfined compressive strength of cement-stabilized Qiantang River silty clay has been proposed with considerations for mixing-water-to-cement ratio and curing time. By comparing the experimental data of the present study with the existing literature data, it is found that there is a unified relationship between the unconfined compressive strength and the mixing-water-to-cement ratio of cement-stabilized Qiantang River silty clay, kaolin, Singapore marine clay, and Bangkok clay under the same curing time. The prediction method recommended by the standard may overestimate the unconfined compressive strength of cement-stabilized Qiantang River silty clay cured for 90 days. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation on the compression behavior of cement-treated dredged slurry at high water content considering the effect of applied curing stress. A series of one-dimensional compression tests were performed on treated samples at various water contents, cement contents, and curing times with and without applied curing stress. Tests result showed that the void ratio versus logarithmic loading pressure curve of all tested specimens exhibits the same decreasing pattern with an obvious yield phenomenon. The void ratio slightly reduces in the pre-yield stage while significantly decreasing with logarithmic loading pressure in the post-yield stage. The magnitude compression index Cs in the pre-yield stage is much lower than that of the value Cc in the post-yield stage. At the same water content and cement content, when the curing pressure is applied, the magnitudes of Cs and Cc are reduced. The yield stress of treated dredged clay samples cured at the same curing time with applied curing stress is higher than that without applied curing stress, indicating that the presence of curing stress has a positive effect on the acquisition of yield stress. It is an effective way to apply curing stress in the actual engineering practice. [ABSTRACT FROM AUTHOR]

Plain concrete is strong in compression but brittle in tension, having a low tensile strain capacity that can significantly degrade the long-term performance of concrete structures, even when steel reinforcing is present. In order to address these challenges, short polymer fibers are randomly dispersed in a cement-based matrix to forma highly ductile engineered cementitious composite (ECC). This material exhibits high ductility under tensile forces, with its tensile strain being several hundred times greater than conventional concrete. Since concrete is inherently weak in tension, the tensile strain capacity (TSC) has become one of the most extensively researched properties. As a result, developing a model to predict the TSC of the ECC and to optimize the mixture proportions becomes challenging. Meanwhile, the effort required for laboratory trial batches to determine the TSC is reduced. To achieve the research objectives, five distinct models, artificial neural network (ANN), nonlinear model (NLR), linear relationship model (LR), multi-logistic model (MLR), and M5P-tree model (M5P), are investigated and employed to predict the TSC of ECC mixtures containing fly ash. Data from115 mixtures are gathered and analyzed to develop a new model. The input variables include mixture proportions, fiber length and diameter, and the time required for curing the various mixtures. The model's effectiveness is evaluated and verified based on statistical parameters such as R², mean absolute error (MAE), scatter index (SI), root mean squared error (RMSE), and objective function (OBJ) value. Consequently, the ANN model outperforms the others in predicting the TSC of the ECC, with RMSE, MAE, OBJ, SI, and R² values of 0.42%, 0.3%, 0.33%, 0.135%, and 0.98, respectively. [ABSTRACT FROM AUTHOR]

This study examines the combined impact of pre-test curing and soaking periods on the soil's resistance to collapse those results from treating gypseous sand with varying amounts of nanoclay. The soil comes from the Iraqi city of Najaf. The soil sample is mainly sand. The nanoclay named "Montmorillonite K10" is used, and it is non-toxic. The tests are performed with a computerized Oedometer. The collapse potential is estimated according to a single Oedometer test (SOT), where the specimens are initially dry and then soaked under a stress level of 200 kPa. Four data sets related to the percentages of 0, 3, 6, and 12% nanoclay are used. Each data set comprises three groups of pre-tests for curing duration and different soaking durations. All experiments have a constant initial dry density of 1.64 g/cm3, water moisture of 3%, and gypsum content of 29%. The findings of this study show that the collapse potential (CP) of natural soil specimens decreases as the pre-test curing time increases. Generally, there is a decrease in CP due to adding the nanoclay and 6% of the nanoclay exhibited the highest reduction in CP. Also, there is an increase in the pre-test curing for the nanoclay-treated soil specimens, which leads to an increase in the CP related to the no-curing state.

The interval time between successive filling processes in a stope is a critical parameter for metal mines. It is imperative to accurately determine this interval time. The relationship curves between curing time and heavy hammer settlement height under various types of cementing materials and slurry concentration conditions were obtained through the self-developed heavy hammer experiment. The mathematical model for the relationship between curing time and heavy hammer settlement height was fitted and regressed, with further analysis of the impact of slurry concentration and cementing material type on initial setting time. The results demonstrate an exponential relationship between curing time and heavy hammer settlement height, wherein the heavy hammer settlement height gradually decreases with increasing curing time. The initial setting time is significantly influenced by both the concentration of slurry and the type of cementing materials. Generally, with the same cementing material conditions, higher backfill concentrations result in shorter initial setting times. When the slurry concentration is 68 %, the initial setting time of A-type cementing materials occurs approximately 36.8 % earlier compared to that of C-type cementing materials, highlighting the crucial significance of selecting appropriate cementing materials for mine filling. The implementation of a consecutive filling strategy based on heavy hammer experimentation holds significant implications for enhancing the efficiency of mine filling, as exemplified by an iron mine in China.

There is a global upsurge in the use of cemented paste backfill (CPB) for various mining functions. However, the cost of the Portland cement binder is prohibitive, thus warranting strategies to reduce cement usage without overly diminishing the CPB quality. Since carbon dioxide is used for patented sand moulding processes, this study is premised on that physicochemical ability of CO2 to enhance the curing of consolidated inorganic materials. It evaluated the impact of carbon dioxide on the uniaxial compressive strength UCS and preparation cost of CPB standard samples (ASTM C109). The preparation cost was delimited to the purchase cost of the Portland cement. The backfill material was silica sand tailings with 4.5 wt.% Portland cement binder and a water-cement ratio of 7.6. Distilled water of pH 5.4 was used for the control samples while variable amounts of carbon dioxide were dissolved in distilled water to generate carbonated mixing water with pH values of 3.8; 4 and 4.2. The lower the carbonated water pH, the higher is the CO2 concentration. UCS tests were conducted on the samples after curing for 3, 7, 28, and 90 days. There was an observable increase in the UCSs and reduction in curing time with increasing carbon dioxide. Samples prepared with carbonated water of pH 3.8 had almost double the strength of those prepared with pure distilled water of pH 5.4, implying that more dissolved CO2 corresponds to higher CPB strength. This is supported by the trendline equations for the graphical simulation of strength on curing time. Thus, CPB with much less binder can be expected to attain the requisite UCS if carbon dioxide is incorporated. The average reduction in Portland cement consumption was 0.61 %, which translates to a cost saving of the same percentage points. If calculated over the operational life of a mine, this is a massive saving of millions of dollars.

Objectives. To improve the technology for obtaining polymer spray coatings based on polycarbodiimides (polyureas) by studying changes in the process and operational parameters due to the introduction of aspartic acid derivatives (AADs) into the composition.Methods. The process of the production of sprayed and contact polyureas involves a number of difficulties, not least in terms of the cost of the components and high-pressure equipment. For this reason, mathematical modeling was used to optimize experimental design. The curing time of the composition was measured under conditions simulated to be close to actual. After thermostating and mixing Components A and B in predetermined ratios, the gelation time was measured to represent the curing time of the composition. The hardness of the material was determined by the Shore method according to GOST 24621-91. Tensile strength and relative elongation were determined according to a standard method (GOST 30436-96).Results. The effect of three AADs on the properties of the finished polyurea was studied. It was found that the introduction of two of them (AAD-1 and AAD-2) into polyurea in an amount of up to 40 wt % produces slow-curing (>250 s) polyureas capable of manual application. The finished products have physical properties on par with machine-poured materials (breaking strength >73 MPa; tensile strength >23 MPa; elongation >500%). Compiled regression equations were used to construct graphs of equal levels showing the possible areas of directed modification of the studied compositions.Conclusions. AAD can be used as a modifying component for polyurea systems to obtain slow-curing polyureas with high performance properties, which can be purposefully controlled by mathematical modeling. The resulting products have commercial value due to their combination of valuable physical and mechanical properties.

Vat photopolymerization-based additive manufacturing is a promising technology for the preparation of ceramic parts, owing to its short fabrication cycle and low manufacturing cost. However, its application is limited due to the low mechanical properties and deformation of ceramic parts. To improve the properties of ceramic parts, changing particle size and printing parameters have been found to be useful. Herein, alumina ceramic parts were prepared using three different powders with different particle size (Powder A: D 50 = 1.3 μm, D 90 = 6.1 μm; Powder B: D 50 = 3.4 μm, D 90 = 10.0 μm; Powder C: D 50 = 1.3 μm, D 90 = 2.8 μm), different layer thickness (50 μm, 75 μm, 100 μm), and different curing times (1 s, 3 s, 5 s, 8 s). The ceramics prepared with Powder A and Powder C, which possessed the same D 50 , had almost the same flexural strength, indicating that the flexural strength is closely related to the particle size and its distribution. With the increase in layer thickness, the flexural strength was increased. When the layer thickness was 100 μm, the flexural strength reached 18.5 MPa when samples were prepared with Powder A and Powder C. At the same time, the flexural strength firstly increased and subsequently decreased with increasing curing time. Based on the flexural strength and shrinkage of the sintered ceramics, using Powder A, layer thickness of 50 μm, and curing time of 5 s were regarded as the best fabrication conditions. The results indicate that adjusting powder particle size distribution, layer thickness, and curing time are promising methods for the fabrication of 3D printed ceramics with optimized properties. [ABSTRACT FROM AUTHOR]

AbstractThis study investigated the strength characteristics of dredged marine clays treated with fly ash with varying porewater salinities. A series of laboratory tests were conducted on fly ash-treated dredged marine clay specimens with various salinities and curing times. In the direct shear tests, observed patterns revealed a consistent initial rapid increase in shear stress with the increase of horizontal displacement, followed by either a gradual decline or stabilization after reaching the peak shear stress. The variation curve consistently positioned the lower salinity or longer curing time above the higher salinity or shorter curing time. Furthermore, the shear strength at a given vertical stress consistently decreases with increasing salinity while ascending with increasing curing time. This indicated that curing time positively influences shear strength development, while the presence of salt negatively affects it. Both strength parameters cohesion and friction angle exhibited growth trends with increased curing time but displayed a decline as salinity increased from 0% to 6%. Unconfined compressive strength test results showed a strain-softening behavior for all tested specimens. The compressive strength demonstrated a declining trend with rising salinity, with a more pronounced decrease observed within the initial 7d compared to the less significant change between 7d and 28d. [ABSTRACT FROM AUTHOR]

The organic and inorganic components of the leachate generated by the uncontrolled and haphazardly stored solid waste landfill through the rain mix with into the groundwater and soil layers and affect the geotechnical properties and dynamic behavior of the soil. In this study, the effect of leachate and the cure time on sandy soil were studied in dynamic triaxial test system. The results were compared clean sand samples tested at different saturation degrees. When the saturation degree is above B=45% both the clean and polluted sand liquefies. As the B value increases sands liquefies at the small number of cycles. As the saturation degree decreases the strength against the liquefaction increases both clean and polluted sand samples. If the B value is below the 45% both the clean sand and the polluted sand cannot liquefied. As the cure time increases the polluted sands liquefies before the clean sands. The organic and inorganic components of the leachate affect sands rather than the chemical reaction with sands. [ABSTRACT FROM AUTHOR]

The advancement of eco-friendly technology in the construction sector has been improving rapidly in the last few years. As a result, multiple building materials were developed, enhanced, and proposed as replacements for some traditional materials. One notable example presents geopolymer as a substitute for ordinary Portland concrete (OPC). The manufacturing process of (OPC) generates CO2 emissions and a high energy demand, both of which contribute to ozone depletion and global warming. The implementation of geopolymer concrete (GPC) technology in the construction sector provides a path to more sustainable growth and a cleaner environment. This is due to geopolymer concrete's ability to reduce environmental pollutants and reduce the construction industry's carbon footprint. This is achieved through its unique composition, which typically involves industrial byproducts like fly ash or slag. These materials, rich in silicon and aluminum, react with alkaline solutions to form a binding gel, bypassing the need for the high-energy clinker production required in OPC. The use of such byproducts not only reduces CO2 emissions but also contributes to waste minimization. Additionally, geopolymer offers extra advantages compared to OPC, including improved mechanical strength, enhanced durability, and good stability in acidic and alkaline settings. Such properties make GPC particularly suitable for a range of construction environments, from industrial applications to infrastructure projects exposed to harsh conditions. This paper comprehensively reviews the different characteristics of geopolymers, which include their composition, compressive strength, durability, and curing methods. Furthermore, the environmental impacts related to the manufacturing of geopolymer materials were evaluated through the life-cycle assessment method. The result demonstrated that geopolymer concrete maintains positive environmental impacts due to the fact that it produces fewer carbon dioxide CO2 emissions compared to OPC concrete during its manufacturing; however, geopolymer concrete had some minor negative environmental impacts, including abiotic depletion, human toxicity, freshwater ecotoxicity, terrestrial ecotoxicity, and acidification. These are important considerations for ongoing research aimed at further improving the sustainability of geopolymer concrete. Moreover, it was determined that silicate content, curing temperature, and the proportion of alkaline solution to binder are the major factors significantly influencing the compressive strength of geopolymer concrete. The advancement of geopolymer technology represents not just a stride toward more sustainable construction practices but also paves the way for innovative approaches in the field of building materials. [ABSTRACT FROM AUTHOR]

Filling mining method can effectively solve the problems of tailings pond collapse and environmental pollution in ore mining production. Cement is the main filling material, but the strength of ordinary cement filling body is low and the filling cost is high. Given this, conventional triaxial tests were carried out on the tailings of Jiaojia gold mine, and the mechanical properties of slag based cementitious agent with different curing time(3, 7, 14 and 28 d) and different confining pressures®, 50, 100, 300 and 500 kPa) were compared with cement. The results show that slag based backfill body can effectively improve the strength of backfill body, and its compressive strength at different curing time is greater than that of cement backfill body. The increase of curing time promotes the transition from plasticity to brittleness, and the increase of confining pressure promotes the transition from brittleness to plasticity. Mogi Coulomb strength criterion is more suitable than Mohr Coulomb strength criterion to evaluate the mechanical properties of full tailings filling in Jiaojia Gold Mine. With the increase of confining pressure, the failure characteristics of the backfill body change from tensile failure to shear failure, and the distribution density of failure cracks decreases. Curing time and cementitious agent type has little effect on the failure mode of backfill body. The test results show that slag based can solve the problems of low strength of backfill body and solid waste storage, which is conducive to the realization of green development of filling mining. [ABSTRACT FROM AUTHOR]

This study examined the mechanical behavior characteristics of cold recycled emulsified asphalt bases with RAP 76% and emulsified asphalt 3%, in different cure time, i.e., 0, 7, 14 and 28 days and evaluated in terms of the resilient modulus (RM) and permanent deformation (PD) based on repeated load triaxial tests. The results demonstrated that in the first 7 days, the RM increased by 80% compared to the freshly compacted material and after this period, the subsequent increases were not as significant, ranging, from 10.9% to 19.4%, that shows that initical cure time significantly influences the RM behavior of the mixtures. However, the mixtures showed considerable permanent deformations, even after 28 days of curing. This indicates that the use of asphalt emulsion, with prolonged curing, improves the mechanical properties of the mixture but does not entirely resolve the issue of permanent deformation in cold reclaimed asphalt mixture (CRAM). The plastic deformation behavior observed in the triaxial tests must be taken into account when designing pavements containing RAP and asphalt emulsion.

In the present research, fountain solution without isopropyl alcohol (IPA) for Ultraviolet offset curing ink (UV ink) was prepared by using Ethylene Glycol Mono-butyl Ether (EGME) as a substitute for IPA. The effect of EGME concentration on the water pick-up characteristics, tack value, rheological behaviors, and curing time of UV offset inks was investigated. Water pick-up characteristics, tack value and rheological behaviors were measured by Duke Ink water emulsification tester, Tack-o-scope and cone-plate rheometer, respectively. The curing time of the UV ink was evaluated by the rub test of printed sheet samples proofed on the polymer film at the standard solid ink density and the same ink thickness. The results revealed that an increase in EGME concentration increased the water pick-up characteristics of the UV ink. There was no significant influence of EGME on the tack value of UV inks. However, the tack value of UV ink was significantly affected by fountain concentration in UV inks and UV ink color. The addition of EGME reduced the dynamic viscosity and thixotropic property of UV inks but did not change the flow behavior of UV ink as shear thinning. This study indicates that UV ink emulsified with a higher EGME concentration fountain solution needs a longer curing time. The cyan UV ink has the longest curing time. Finally, the fountain solution of 10% EGME exhibited good performance in water pick-up characteristics, tack value, rheological behaviors, and curing time of UV inks.

Seashell is a hard, protective outer layer created by an animal that lives in the sea. Empty seashells are often found washed up on beaches by beachcombers. This marine by-product can be used to partial replacement of coarse aggregate or cement in concrete. This paper describes the use of seashell powder and aggregate in the concrete for the replacement of cement and coarse aggregate. The effect of seashell waste in the concrete was studied in terms of its compressive strength, tensile strength and flexural strength after 28, 56 and 90 days of curing. The replacement of cement by seashell powder were 10%, 20% and 30% and replacement of coarse aggregate by seashell aggregate are 5%, 10% and 15%. The properties of seashell concrete were compared with control mix specimen of M25 grade of concrete. Also, it has been tried to predict the strength of the seashell concrete utilizing adaptive neuro-fuzzy inference system (ANFIS). The prediction of strength with the tool was agreeable with the experimental strength with the minimal error of less than 5%. This study concludes, that partial replacement of cement and coarse aggregate by seashell waste enhances the mechanical properties of the concrete significantly and enable proper utilization of these seashell waste as sustainable material for the concrete.

Cold asphalt mixtures are more sustainable because they are manufactured at ambient temperature. However, they are much less applied because they take longer time in the curing process due to the water contained in the asphalt emulsion, which delays the opening of roads. To solve this problem, the option of adding magnetic aggregates to cold asphalt mixtures and heating them by magnetic induction to evaporate the water contained in the asphalt emulsion and reduce curing time has been evaluated. For this objective, different by-products were evaluated as magnetic aggregate and the best one was selected. Four porous asphalt mixtures were then manufactured: an experimental mixture with the selected magnetic particles, a control mixture with virgin steel instead of the by-products, and two oven-cured reference mixtures without magnetic aggregate (one according to the Spanish standard and another according to the U.S. Asphalt Institute guidelines); then, the four mixtures were studied in terms of the curing process, rheological properties of bitumen and mechanical performance of samples. The experimental mixture containing industrial by-products shortened the curing time from 7 and 2 days (Spanish and U.S. Asphalt Institute standard, respectively) to only two hours; rheological and mechanical analysis proved the viability of this technology.

The share of buildings in energy consumption and global greenhouse gas emissions is significant. Lime mortars are common in traditional architecture, but due to their mechanical disadvantages compared to cement, they were excluded from modern constructions. It can significantly contribute to environmental sustainability by replacing modified lime mortars with common cement mortars, particularly in the building envelope system. Conventional lime-based roof pastes (LRP) are multilayer complicated systems composed of various ingredients and binders; their physical properties define the function of LRPs: interact connection, underlayer contact, and external variables. Lime pastes sets as a durable and generally flexible solid mass. It is breathable and permits the transfer and evaporation of moisture. It is less susceptible to water and won't dry or disintegrate, unlike clay or gypsum paste. Pastes made of hydrated lime are less brittle and breakable, and as building insulation materials (Bims), a lime-based paste is used against environmental concerns. Microstructure and material characterization tests, compressive strength, and strain were used to identify, characterize, and evaluate the LRP. The dispersive energy X-ray (EDX) and X-ray fluorescence (XRF) indicated that LRP is composed of two main compounds, SiO2 and CaO, which are primarily converted to calcium silicate and calcium carbonate during the hydration process. The thermogravimetric analysis (TGA) findings demonstrated that the material exhibited high thermal stability up to 200 °C and 11.4% weight loss at 975 °C, demonstrating the high heat capacity of the LRP and fire resistance. At 28 days of curing, the compressive strength of the LRP with water to binder ratio (w/b) of 0.75 and 0.60 was 0.761 and 1.094 MPa, respectively. The stress-strain relationships of the LRP were predicted using three independent mathematical models, including the rational, β, and Vipulanandan p-q models. Based on the coefficient of determination R2 and root mean square error (RMSE), the best model for predicting the compression stress-strain behavior of the LRP at various w/b and curing times was the Vipulanandan p-q model. [ABSTRACT FROM AUTHOR]

Evaluation of mechanical behavior of the soil-structure interface has been the focus of many researchers as an effective factor on the strength performance and deformation of the structure. Since the interaction of the structure and the soils around it will have a great impact on the soil bearing capacity, it is important to study the physical conditions. In this study, taking into account the curing time, effect of using Persian gum and the roughness of the steel on the behavior of the soil-structure interface using large-scale direct shear test have been investigated. The Persian gum was used in three amounts of 0.3, 0.6 and 0.9% on three smooth, rough and geotextile covered surfaces. Based on the results, by injecting Persian gum into the soil-candle interface, the adhesion between soil and contact surface increases by about 20 times and the internal friction angle increases by one degree. The rate of increase of strength parameters decreases with increasing curing time. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office 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.)

This study involves an experimental examination of compression behaviors of fly ash stabilized marine clay cured at different times concerning the influences of pore water salinity. A set of laboratory one-dimensional compression tests was conducted on soft Lianyungang marine clay specimens with various pore water salinities and stabilized with fly ash. Test results indicated that both salinity and curing time influenced the compression characteristic of fly ash stabilized clay. The presence of fly ash obviously reduced the compressibility of the untreated marine clay sample. The semi-logarithmic compression curve of untreated pure soil was a straight line, whereas fly ash stabilized clay samples exhibited the pattern of two straight lines. All the fly ash stabilized soil specimens were well represented by two straight lines in the bilogarithmic coordinate, making it convenient to determine the compression yield stress. The compression index at the pre-yield stage was not susceptible to the variation in the salinity and curing period, whereas at the post-yield stage it exhibited a downward tendency as salinity and curing time increased. The value of yield stress for stabilized marine clay specimen exhibited a downward tendency with increasing salinity, whereas it increased significantly within 7 days and tended to level off with the elapsed curing time. The adverse effect of salinity and the positive influence of curing time on yield stress should be considered in engineering applications. [ABSTRACT FROM AUTHOR]

By preparing fine tailings slurry with different mass concentration and fiber content, the rheological parameters of slurry with different fiber content and curing time were tested. In addition, the influence law of fiber content and curing time on compressive strength was analyzed through the prepared fine tailings backfill samples, and the microstructure characteristics of fine tailings backfill were further studied. The results show that when the fiber content is 0.2 ~ 1.2%, the yield stress and plastic viscosity of the slurry increase with the increase of fiber content, and the thixotropy of the slurry also shows the same change characteristics. The bridge effect of fiber makes it easier for forming network structure, which increase the slurry rheology. When the curing time ranges from 0 h to 2.5 h, the increasing of curing time leads to the increasing trend of rheological parameters, and also increases the thixotropy of slurry. However, the increase of rheological parameters will continuously decrease when the curing time exceeds 1 h, indicating that the influence of curing time on yield stress and thixotropy will gradually weaken with the continuous extension of curing time. When the curing age increases from 3 to 56 days, the compressive strength of the fine tailings backfill increases with the curing age, but the increasing range of compressive strength decreases gradually. When the fiber content ranges from 0.2 to 1.2%, the compressive strength of backfill increases first and then decreases with the increase of fiber content, and reaches the maximum value when the fiber content is 0.6%. The extension of curing time reduces the generation of large-scale pore structure, which promotes the formation of more compact microstructure of backfill. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ground Improvement is the property of Journal of Ground Improvement Editorial Office 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.)

Background. This study aimed to measure the shear bond strength and compressive strength of orthodontic adhesives at different curing times and intensities. Methods. Ninety extracted human premolars were used. Orthodontic brackets were bonded on the buccal surface of the teeth with orthodontic adhesive light-cured using VRN-VAFU LED curing light at different curing times (1, 3 and 5 seconds) and intensities (1000, 1600 and 2300 mW/cm2 ). A universal testing machine was used to measure the shear bond strength. The ratio of the adhesive remnant and compressive strength of the orthodontic adhesive, at each curing time at the different intensities, were also evaluated. The results were statistically analyzed using one-way analysis of variance followed by Tukey’s test. Results. The lowest bond strength values (6.4, 9.9 and 12.6 MPa) were recorded with 1000 mW/ cm2 intensity (at all curing times) in comparison with the other intensities (P

Protecting stone on facades or exterior art works from deterioration is primarily about protecting them from rainwater. Hydrophobic coatings are widely used for this purpose. Here, two factors affecting the long-term efficiency of some coatings applied on stones were investigated: the number of coating layers and the curing time after their application. Tests of water absorption by capillarity, absorption at total immersion in water, and a visual check of the penetration depth have been carried out. The coating’s efficiency coefficient Cef was defined as the ratio of the maximum water absorption of a treated sample to an untreated one. Two commercial silicon-based coatings were applied on the highly porous Hořice sandstone alternatively. Curing times of 2 days vs. 2 weeks, and 2 coating layers vs. 3 layers were compared. The experiments showed that the coating’s efficiency is affected more by the curing time than by the number of applied coating layers. The curing time of 2 days after coating’s application is too short, but 2 weeks proved to be sufficient for both tested coatings. There was no big difference regarding the number of coating layers; two layers seem to be sufficient if a long rain-free curing time can be guaranteed.

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office 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.)