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Purpose: To evaluate the influence of abutment material, cement thickness, and crown type on the esthe:cs of implant supported restora:ons. Material and Methods: In total, 60 specimens were prepared to represent six abutment groups: Group PA = pink-anodized Ti; Group GA = gold-anodized Ti; Group T = nonanodized Ti; Group H = hybrid (Ti + zirconia); Group P = PEEK (Ti + PEEK); and Group C = composite resin (control). Crown specimens (n = 120) were obtained from Vita Enamic (VE) and Vita Suprinity (VS). Two cement thicknesses (0.1 and 0.2 mm) were used. The color values of crown configura:ons were measured and E00* values were calculated. Sta:s:cal analyses included were Shapiro Wilk, three-way ANOVA, and Tukey HSD tests (P £ .05). Results: Abutment (P < .001) and crown materials (P = .001) had a significant effect on E00* values, while cement thickness did not. Groups PA and H resulted in significantly lower mean E00* values than other abutments, whereas Group T revealed the highest. Unlike VS, cement thicknesses created a significant difference on the E00* values for VE (P £ .05). Conclusions: Pink-anodized Ti or hybrid abutments for VE and pink- or goldanodized Ti for VS seem to be better options, in terms of color change. Cement thickness of 0.1 mm resulted in higher E00* value than 0.2 mm for VE (P £ .05). Int J Prosthodont. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the esthetic outcomes based on the color differences in zirconia (Zr) of varying thickness, resin cement color, and types of titanium (Ti) implant surface treatments. Materials and Methods: Overall, 28 high-translucency monolithic zirconia (HTMZ) specimens were arranged into four groups based on Zr thickness: 1.0, 1.5, 2.0, and 2.5 mm (n = 7 per thickness). Each group was tested using two resin cement colors (clear and opaque) in combination with six surface-treated Ti groups (n = 7), including untreated titanium (UT), anodization (AN), 50-µm alumina airborne-particle abrasion followed by AN (SBAN), AN followed by 50-µm alumina airborne-particle abrasion (ANSB), 9.5% hydrofluoric acid followed by AN (HFAN), and AN followed by 9.5% hydrofluoric acid (ANHF). This created a total of 48 experimental groups, including the use of composite resin (n = 7, shade A2D) for four control groups. All specimens were measured using a spectrophotometer and subsequently compared with composite resin (control) with the corresponding Zr thickness to establish color differences. A color difference of < 2.7 was considered clinically acceptable. The data obtained were statistically analyzed using ANOVA and post hoc test (P = .05). Results: Zr thickness, resin cement color, and type of Ti implant surface treatment significantly affected the observed color differences (P < .05). When using 2.5-mm HTMZ with clear resin cement on AN, UT, SBAN, HFAN, and ANSB, the mean color differences were below the clinically acceptable values, and the 95% CIs of color differences were below the clinically acceptable values for AN, UT, and SBAN groups. Conclusions: HTMZ with a minimum thickness of 2.5 mm and clear resin cement on AN, UT, and SBAN groups potentially result in acceptable color matching with 95% CIs. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the resistance of an implant crown telescopically engaged to a geometrically defined hexagonal abutment with and without cement under compressive dynamic cyclic fatigue loading. Materials and Methods: 40 crowns, 9 mm in height, were cast from prefabricated plastic copings, each telescopically engaged to a 3-mm-high machined hexagonal abutment. 20 crowns were retained with zinc phosphate cement, and 20 crowns were retained with a screw. A vertical load of 15 kg was applied to all samples under oscilla)on. A Periotest was used to measure the mobility of the implant crown in Periotest values (PTV). Test endpoints were defined by the following: fa)gue cycles ≥ 20 million; crown PTV > 10; or if samples became visibly loose or component fracture. Results: Cement-retained crowns failed on average at 2.60 x 106 cycles ± 2.27, while screw-retained crown samples failed at 2.17 x 106 cycles ± 1.27 with no significant difference (P > .05). Implant and abutment screw fractures were the most prevalent mode of failure in the cement-retained group, while in the screw-retained group, failures were caused by the loosening of one or both screw joints. The rate of increase in PTV was higher in the screw-retained group than in the cement-retained group. Conclusions: Under the experimental condi)ons, an implant crown telescopically engaged ver)cally to a 3-mm-tall hexagonal abutment, under compressive dynamic cyclic fa)gue loading with or without cement, demonstrated no differences in resistance or failure outcomes. A cement-retained implant crown with telescopic engagement to the abutment is more rigid, resul)ng in more implant and abutment screw fractures than loosening. [ABSTRACT FROM AUTHOR]

Purpose: To develop the most compatible cementation protocol for ensuring minimal residual cement and optimal retention of cement-retained implant-supported fixed dental prostheses. Materials and Methods: A total of 30 custom implant abutments and zirconia crowns with bilateral wings were prepared. Three cement types were used for cementation: noneugenol resin cement (Premier Implant Cement; Group IC), dual-polymerizing self-adhesive resin cement (SmartCem2; Group SC), and zinc oxide eugenol cement (Temp-Bond; Group TB; n = 30 per group). Three cementation methods were applied for each cement type, and the samples were divided into subgroups: (1) cement was injected using a graduated syringe (ICN, SC-N, and TB-N); (2) a cementation jig made with a silicone impression material and temporary resin material was used (IC-CJ, SC-CJ, and TB-CJ); (3) 3D-printed abutments were used as replicas for cementation (IC-3DP, SC-3DP, and TB-3DP). The amount of cement injected, surface area of the residual cement, and retentive strength were measured. Kruskal-Wallis and post-hoc Mann-Whitney tests were used for statistical analyses. Results: Excess cement was not observed when cementation jig or 3D-printed replicas were used. For IC and SC subgroups, non-use of these auxiliary tools resulted in significantly higher amounts of injected cement. The retentive strength differed significantly among the IC subgroups but not among the SC subgroups. The retentive strength of subgroups TB-N and TB-CJ was significantly higher than that of subgroup TB-3DP. Conclusions: To prolong the main purpose of each cement type, a cementation jig or 3D-printed replica is highly recommended regardless of the cement type. [ABSTRACT FROM AUTHOR]

Recent California regulatory efforts, United States goals, and industry roadmaps all target net-zero greenhouse gas (GHG) emissions from the cement and concrete industries within a few decades. While changes in production of cement and concrete, including varying constituents, can greatly reduce GHG emissions, carbon dioxide removal (CDR) will be needed to meet this net-zero goal. Hydrated cement in concrete can carbonate (i.e., form carbon-based minerals with atmospheric CO2) and thus act as a CDR mechanism. This process occurs faster with a large surface area, such as crushed concrete at its end-of-life (EoL), which can be uniquely leveraged by transportation infrastructure projects. In this work, a literature review of key parameters that can facilitate desired CO2 uptake for transportation projects at their end of life is conducted and an initial meta-analyses of data from the literature to inform CO2 uptake for individual projects is performed. Initial considerations for what concomitant impacts may arise from this process are presented. Finally, experiments to fill a key gap in understanding how thin crushed concrete must be spread to maximize uptake reactions are conducted. Cumulatively, findings will inform whether carbonation can be implementedin a way that would support policies that include carbonation as a route for reducing emissions from cement-based materials in transportation applicationsView the NCST Project Webpage

Carpal giant cell tumor of bone spanning multiple bones is a rare condition. We present a case of a man in his fifth decade with wrist pain who was found to have giant cell tumor of bone involving his capitate and hamate bones. This condition was successfully treated with intralesional curettage, argon beam coagulation, chemical cauterization and a cemented limited carpal fusion with satisfactory outcomes and no recurrence at 1-year postoperative follow-up.

Purpose: To evaluate the effect of simulated gastric acid solution (SGAS) and resin cement composition on the shear bond strength (SBS) of zirconia-based materials with different levels of translucency to composite resin. Materials and Methods: A total of 40 medium-opacity (MO; 3Y-TZP) and 40 medium-translucency (MT; 4Y-PSZ) zirconia slabs were distributed into four groups according to the composition of the resin luting system (MDP free or with MDP [primer + Panavia V5]) and storage method (distilled water or SGAS [5% hydrochloric acid]). Composite resin cylinders were cemented on the zirconia surface and stored for 91 hours. SBS, failure mode, and surface characterization analyses via scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were performed. SBS data were analyzed using three-way ANOVA and Tukey tests, and failure mode was assessed using one-way ANOVA (P < .05). Results: Storage media (P = .180), resin cement (P = .110), zirconia (P = .404), and their interactions did not affect SBS values. Bond strength ranged from 21.41 to 26.11 MPa. SEM images showed that SGAS modified the surface topography of zirconia and resin cement. The presence of chlorine and silicon (wt%) were higher after SGAS storage than after water storage in both cements used, while barium was higher only for the MDP cement. There was a prevalence of mixed failures for most of the groups. Conclusions: The SBS between both types of zirconia and resin cement was not affected by SGAS, although changes in zirconia topography were observed after SGAS exposure. The presence of MDP in the cement layer had no effect on the SBS challenged by SGAS. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the marginal integrity of three inlay-retained fixed dental prosthesis (IRFDP) designs fabricated using monolithic zirconia. Materials and Methods: In total, 30 IRFDPs were fabricated using 4-YTZP monolithic zirconia and randomly divided into three groups according to the cavity design. Groups ID2 and ID1.5 received an inlay cavity preparation, which includes a proximal box and an occlusal extension with a depth of 2 mm or 1.5 mm, respectively. Group PB received a proximal box cavity preparation without an occlusal extension. The restorations were fabricated and cemented using a dual-cure resin cement (Panavia V5) and subjected to an equivalent of 5 years of aging. The specimens were evaluated under an SEM to measure marginal continuity before and after the aging process. Results: During the whole 5-year aging process, no specimens showed signs of cracking, fracture, or loss of retention in any restorations. In the SEM analysis, most marginal defects observed in the restorations were areas of microgaps at the tooth/ cement interface (TC) or zirconia/cement interface (ZC), resulting in loss of adaptation. There was a significant difference between the groups after the aging process at both the TC (F = 4.762, P < .05) and ZC (F = 6.975, P < .05), with Group ID2 presenting the best performance. There was a significant difference between TC and ZC in all groups (P < .05), with ZC presenting more gaps in all groups. Conclusions: Inlay cavity designs including a proximal box and an occlusal extension exhibited better marginal stability than a proximal box without occlusal extension. [ABSTRACT FROM AUTHOR]

China’s cement industry emits over 1 Gt of carbon dioxide (CO2) annually, or 3% of global CO2 emissions.Urgent decarbonization efforts of the Chinese cement industry are needed to meet China and global community’s climate commitments. Prior studies on this topic primarily relied on supply-side technologies and end-of-pipe solutions, presenting one singular pathway to net zero without exploring multiple trajectories.This study adds value to the existing research by constructing and evaluating two different pathways toward net-zero emissions in China’s cement industry: the Energy Technology Pathway (ETP) and the Circular Economy Pathway (CEP). Both pathways aim for net-zero emissions but diverge in their prioritization and emphasis. The Energy Technology Pathway focused on supply-side technologies such as green hydrogen and CCS, while the Circular Economy Pathway focused on demand-side strategies, centered on materials and resources.The study showed both pathways can achieve a comparable level of emission reduction, reducing 94-95% of CO2 emissions by 2060 from the 2020 level. Notably, the role of CCS is limited in the CEP, contributing only 5% and 22% of total emission reductions by 2030 and 2060, respectively. The majority of the emission reductions in CEP are achieved through a combination of material-focused innovations and circular economy strategies, such as increasing the use of supplemental cementitious materials (SCMs), advancing alternative cements, integrating material efficiency practices in product lifecycle phases, and adopting alternative fuels (e.g., industrial wastes and agricultural byproducts). Policy support on materials and the circular economy will be critical. We recommend updating codes and standards to allow performance-based cement products, providing R&D support on alternative cements, developing implementation guides to disseminate material efficiency practices, and improving material/waste collection, sorting, and recycling systems.

Freezing of water under nanoconfinement exhibits physical peculiarities with respect to the bulk water. However, experimental observations are extremely challenging at this scale, which limits our understanding of the effect of confinement on water properties upon freezing. In this study, we use molecular dynamic simulations to investigate how confinement affects the kinetics of growth of ice and the thermodynamic equilibrium of ice-liquid coexistence. TIP4P/Ice water model and CSH-FF model were applied to simulate ice crystallization in a confined cement system at temperatures down to 220 K. We adapted an interface detection algorithm and reparameterized the CHILL/CHILL+ algorithm to capture ice growth. The confinement leads to a shift of the maximum growth rate of ice to a higher temperature than for bulk water. Both the confinement and surface impurities contribute to slowing down the ice growth. For the ice-liquid coexistence at equilibrium, we derive a formulation of Thomson's equation adapted to statistical physics quantities accessible by molecular simulation, and we show that this adapted equation predicts accurately the melting line of bulk and confined ice Ih as a function of pressure. The confinement decreases systematically the melting temperature of ice of about 5 K compared with bulk ice Ih. A premelted water film about 1 nm thick is observed between the solid wall and ice, and its thickness is found to decrease continuously as temperature is lowered. We note that the surface impurities are key to the formation of the premelted water nanofilm when the temperature is lower than 250 K. [ABSTRACT FROM AUTHOR]

The present investigation involved the collection of various construction materials from several sites throughout the Mangalore District, Karnataka, India. The concentration of radionuclides in each sample was then determined using a NaI(Tl) detector. The passive 'Can' technique method was used to determine the rate of radon exhalation in the collected samples. The activity concentration of 40K ranges from 36.53 Bq kg−1 to 80.68 Bq kg−1. The activity concentration of 226Ra ranges from 23.30 Bq kg−1 to 80.87 Bq kg−1. The 232Th activity concentration found to be lowest is 15.06 Bq kg−1 and a maximum of 38.65 Bq kg−1 in different samples. The estimated Activity Utilisation index (AUI), dose rate (D) and gamma index (Iγ) which is lower than the recommended limit. The hazard index values are below the Indian, World average and below the safety limit, which indicates that construction materials are safe to use for construction purposes. The present investigation gives insight on radiation hazards to the human population used in the selected location. [ABSTRACT FROM AUTHOR]

The meso‐structure of pervious concrete significantly influences its overall performance. Accurately identifying the meso‐structure of pervious concrete is imperative for optimizing the design of pervious concrete, considering its mechanical properties and functionality. Therefore, to address the difficulty of recognizing the meso‐structures of pervious concrete, a method utilizing deep learning image semantic segmentation techniques is proposed in this study. First, based on the classical deep learning model, three models, namely, Res‐UNet, ED‐SegNet, and G‐ENet, are proposed for recognizing pervious concrete meso‐structure using deep learning image semantic segmentation techniques. These models introduce a residual module, a hybrid loss function, and a differential recognition branching structure to enhance the ability to recognize detailed information within pervious concrete meso‐structure and small targets. Second, the respective recognition performances of these methods on the meso‐structure of pervious concrete were thoroughly analyzed by experiment. The results indicate that the proposed three recognition methods for recognizing the meso‐structure of permeable concrete outperform conventional techniques not only in terms of efficiency but also in recognition accuracy and the ability to distinguish and identify aggregates, pores, and cement binders. In terms of comprehensive recognition effectiveness, the Res‐UNet model outperforms, followed by ED‐SegNet and G‐ENet. Furthermore, the computational efficiency of these three recognition methods meets the requirements of engineering applications. [ABSTRACT FROM AUTHOR]

The aggregation of graphene oxide (GO) in alkaline solutions is a critical factor that limits its potential applications in cement-based materials. In this study, a polycarboxylate superplasticiser (PCE) was employed as a dispersant and a GO–PCE water-reducing agent was synthesised through the method of dropwise addition. This synthesis approach not only preserved the water-reducing capabilities of PCE but also enhanced the dispersibility of GO in alkaline cement solutions. Furthermore, the synthesis method is straightforward. The results showed that that GO–PCE had excellent dispersion in a saturated calcium hydroxide (CH) solution. Furthermore, it was found that the GO–PCE enhanced the workability of cement, accelerated cement hydration, reduced the crystallite size of the CH and increased the compressive strength of the cement mortar. [ABSTRACT FROM AUTHOR]

In this study, the use of meta-schist as an alternative to sand–clay in preparing cement raw mixtures was investigated for the first time. To produce the highest quality Portland cement clinker by examining the mineral and chemical properties of meta-schists, two different raw meal samples were prepared, utilising conventional cement clay as a baseline sample ((PC)Ref) and the other with meta-schist ((PC)MSC). The effects of both raw mixtures on burnability tests and reactivity were evaluated based on the unreacted lime content in samples after they had been sintered at 1200, 1300, 1350, 1400 and 1450°C. The porosity amount, distribution, grain structure of silicate phase crystals, and equivalent crystal diameters and amounts of meta-schist clinker phases (C3S, C2S, C3A and C4AF) examined by polarising optical microscope showed that they are suitable for the production of PC. The hydration products of the cement mortars were determined by scanning electron microscopy and energy-dispersive X-ray analysis at 2, 7 and 28 days. In addition, the compressive strength test results of (PC)MSC and (PC)Ref mortars after 28 days of curing ranged between 57 and 55.5 MPa, and the cement produced was classified as CEM I 42.5R. [ABSTRACT FROM AUTHOR]

The low activity of stainless steel slag (SSS), primarily attributed to its high γ-C2S and low C3S content, impedes its effective utilisation. A thermochemical high-temperature reconstruction method using lime and bauxite as tempering agents to regulate the mineral phase was investigated in this work. Through an array of tests and analytical techniques, including compressive strength tests, activity index evaluation, X-ray diffraction, scanning electron microscopy and hydration heat analysis, the impacts of the calcium/silicon mass (CSM) ratio and the sintering temperature on the mechanical properties and activity of reconstituted SSS mortar were examined. It was found that, at a CSM ratio of 4.2 and a sintering temperature of 1290°C, the reconstructed slag demonstrated optimal mechanical properties and activity, yielding compressive strengths of 43.69 MPa and 62.58 MPa at 7 days and 28 days, respectively, with remarkable 28-day activity index of 143.49%. The proposed thermochemical high-temperature reconstruction method ingeniously employs high temperature to increase the content of C3S while rapid cooling prevents alteration of the C2S crystalline structure. This innovation significantly enhanced the mechanical properties and activity of the SSS, offering promising avenues to increase its utilisation rate. [ABSTRACT FROM AUTHOR]

Progressive osteolysis can occur at the cement–bone interface of joint replacements and the associated loss of fixation can lead to clinical loosening. We previously developed a rat hemiarthroplasty model that exhibited progressive loss of fixation with the development of cement–bone gaps under the tibial tray that mimicked patterns found in human arthroplasty retrievals. Here we explored the ability of a bisphosphonate (zoledronic acid, ZA) to attenuate cement–bone osteolysis and maintain implant stability. Sprague‐Dawley rats (n = 59) received a poly(methylmethacrylate) cemented tibial component and were followed for up to 12 weeks. Treatment groups included peri‐operative administration of ZA (ZA group), administration of ZA at 6 weeks postop (late ZA group), or vehicle (Veh group). There was a 60% reduction in the rate of cement–bone gap formation for the ZA group (0.15 mm3/week) compared to Veh group (0.38 mm3/week, p = 0.016). Late ZA prevented further progression of gap formation but did not reverse bone loss to the level achieved in the ZA group. Micromotion from five times body weight toggle loading was positively correlated with cement–bone gap volume (p = 0.009) and negatively correlated with the amount of cement in the metaphysis (p = 0.005). Reduced new bone formation and enduring nonviable bone in the epiphysis for the ZA group were found. This suggests that low bone turnover in the epiphysis may suppress the early catabolic response due to implantation, thereby maintaining better fixation in the epiphysis. This preclinical model presents compelling supporting data documenting improved maintenance of the cement–bone fixation with the use of peri‐operative bisphosphonates. [ABSTRACT FROM AUTHOR]

This study draws inspiration from the chelating abilities of dopamine and tannic acids with Ca2+ in cement-based materials and explores the potential of green tea water (GTW) with tea polyphenols (TP) as the major soluble substance as a natural source of polyphenols available in people's daily lives. Hydration kinetics analysis reveals that GTW has both retarding and accelerating effects on cement hydration, with the latter being more prominent at lower concentrations. Properly adding GTW to cement can increase the compressive strengths of mortars by up to 16.7% at 3d, 12.2% at 7d, and 18.2% at 28d compared to the blank mortar. The microstructure of the optimal mortar shows grape-cluster-like nanoparticles that originate from the TP∼Ca intermediates that act as seeds for more hydration products. This effect is confirmed by using analytically pure TP to analyze its influence on the compressive strength of mortar. [ABSTRACT FROM AUTHOR]

Effects of polycarboxylate ethers (PCEs) with different charge densities on the time-dependent rheological property (yield stress) were systematically investigated by correlating the charge density of PCE with its adsorption behavior, dispersion capability (including the dispersion rate and dispersion extent), and packing density, fluidity, and hydration kinetics of the cement slurry. Results show that with the increase of charge density, the adsorption rate of PCE increases, which is attributed to the increase of affinity between PCE and cement particles. Based on this, the dispersion rate of PCE is effectively enhanced by increasing its density charge, which results in a faster packing rate, consequently lowering the decrease of the time-dependent yield stress of cement slurry and increasing the fluidity loss over time. Noticeably, the stronger affinity raised from higher charge density leaves fewer PCEs in the solution of cement slurry, which is remarkable at high dosage, and thus leading to a faster fluidity loss or time-dependent yield stress increase. This will also lead to slower hydration kinetics with the same PCE content. These findings can provide guidance for the design of PCE structures in regulating the workability of concrete. [ABSTRACT FROM AUTHOR]

To enhance the early strength development of lithium slag composite binder, synergistic action of calcium silicate hydrates (C─ S─ Hs)–polycarboxylate (PCE) and Al2(SO4)3 on the hydration properties of lithium slag–cement binder was studied. Results showed that C─ S─ H─ PCE and Al2(SO4)3 synergistically facilitated the solidification and hardening of composite binder. The combination of 2% C─ S─ H─ PCE and 6% Al2(SO4)3 enhanced the compressive strength of the composite cement mortar at 1 day, 3 days, and 28 days by 37.6%, 33.1%, and 9.9%, respectively. By providing nucleation sites, C─ S─ H─ PCE facilitated the early hydration of silicates and the pozzolanic reaction of lithium slag, leading to shortened induction period, advanced heat release peak, increased total hydration heat release, and increased production of portlandite (CH) crystals. Aluminum sulfate facilitated dissolution of lithium slag (LS) and expedited the production of ettringite (AFt). The synergistic adoption of C─ S─ H─ PCE and Al2(SO4)3 facilitated the hydration of both clinker and LS, and the hydration products were more abundant, contributing to a more compact matrix. [ABSTRACT FROM AUTHOR]

Recycled cement paste (RCP) is a CaO-rich resource that is recycled from waste concrete and waste cement. For reducing environmental impact and promoting comprehensive resource utilization, RCP could partially replace lime as flux in electric arc furnace (EAF) steelmaking process. In this study, the dissolution behaviors of RCP and lime in EAF slag at 1400 °C and 1500 °C were investigated using static dissolution experiments. The measured dissolution rate constant of lime at 1400 °C and 1500 °C is 3.12×10−5 and 8.42×10−5 m/s, respectively, while that for RCP is 1.37×10−4 and 2.91×10−4 m/s, respectively. For the lime dissolution, a dense dicalcium silicate (C2S) product layer was generated at the dissolution interface, with the diffusion of Ca2+ in the C2S layer being the limiting step for the lime dissolution. However, for the RCP dissolution, no product layer was observed at the dissolution interface. Instead, a dissolution intermediate layer forms due to slag penetration. During the dissolution of RCP, Ca2+ and SiO44− diffuse from RCP layer to slag, while Fe2+ and AlO45− diffuse from slag to RCP layer accumulating in the dissolution intermediate layer. Furthermore, a dissolution model was developed based on current experimental results, which helps to predict dynamic dissolution process of lime and RCP in EAF slag. In general, the dissolution rate of RCP in EAF slag was much higher than that of lime, partially adding RCP as flux in EAF could accelerate the liquid slag formation in EAF steelmaking process. [ABSTRACT FROM AUTHOR]

This study concentrated on producing limestone calcined clay calcium sulfoaluminate cement by replacing portland cement in limestone calcined clay cement with calcium sulfoaluminate cement, with the goal of increasing the early strength of limestone calcined clay cement. The mineralogy and microstructures of hydrating pastes were investigated using x-ray diffraction and scanning electron microscopy. Heat evolution was studied using isothermal calorimetry. Strength development and workability were assessed on mortar samples. The 1 day strengths of limestone calcined clay calcium sulfoaluminate cement samples exceeded those of limestone calcined clay cement by ~ 30–80%, though its strength gain slows significantly after 1 day due to the lack of calcium silicates, affecting pH and clay dissolution. Despite this, the strength development of limestone calcined clay calcium sulfoaluminate cement, when adjusted for CO2 emissions, is comparable to limestone calcined clay cement. Additionally, limestone calcined clay calcium sulfoaluminate cement provides a 10–15% higher flow and exhibits a lower heat of hydration beyond 12 h, while maintaining a production cost similar to that of limestone calcined clay cement. [ABSTRACT FROM AUTHOR]

Cement and concrete are the most crucial and dominating engineering materials in the construction sector. Cement serves as an excellent binder for concrete and when it is treated under unusual conditions either to satisfy accelerating or retarding requirements by the construction industries, admixtures role comes into the effect. The construction industry has been searching for retarding admixtures and the optimal dosage level, particularly for ready mix concrete applications. Generally the retarding admixtures such as organic retarders (lignosulphonates, hydroxycarboxylic acids and their salts, phosphonates, sugars) or inorganic retarders (phosphonates, borates) were generally used to reduce the speed of the reaction between cement and water by altering the growth of the hydration products and/or limiting the rate of water penetration to the cement particles. The research was still in its infancy stage in terms of determining not just the appropriate dosage amount, but also the ideal retarder materials for the aforementioned uses. In considering this industrial need, an attempt was made on utilizing the usage of sugar in the concrete to study the retarding effect without affecting the strength properties of cement. The sugars usage levels were at 5, 10, 15, and 20% of the usage of cement to investigate consistency, setting time, compressive strength and micro structure properties at the curing age of 7, 14 and 28 days on the mortar specimens. The conclusions of the study reported that setting time was extended with increase of the dosage levels of sugar. However in considering the strength property, less than 5% of sugar dosage level can be better for the application as retarding agent in the industry applications. [ABSTRACT FROM AUTHOR]

Cement‐based materials can be modified for microwave reflection/absorption. Admixtures (particles or short fibers) include conductive, dielectric, and magnetic ones, used solely or in combination. Synergism occurs with conductive and magnetic admixtures, due to the enabled eddy current. The conductive admixture promotes absorption and reflection, whether steel rebars are present or not. Regardless of the admixtures, rebars, or aggregates, absorption loss dominates over reflection loss. Steel microfiber is more effective than carbon fiber. Fly ash enhances the absorption slightly, due to the included iron oxide. Because of the skin effect, a small admixture unit size is preferred. Thus, carbon nanofiber is more effective than carbon fiber, if it is adequately dispersed. Fine particles (such as silica fume) as an additional admixture help the dispersion. Nanoscale admixtures tend to fill the pores, so their functional effectiveness is limited. Carbon black (nanoparticles) is less effective than carbon fiber, but it is inexpensive and the combined use of carbon fiber and carbon black is effective. The high cost of the nanofibers and the difficulty of their dispersion limit their practicality. Another approach involves porous admixtures or aggregates for reducing the impedance mismatch so that reflection is lessened and more radiation enters the cement‐based material. [ABSTRACT FROM AUTHOR]

A thorough and comprehensive knowledge of the evolutionary pattern in the thermal-hydraulic-mechanical-chemical (THMC) behavior of cement-stabilized clay is essential for a more reasonable design of improved clay in practical engineering. Sensitive marine clays with low strength, reinforced by various cement contents (0%, 6%, and 12%), were produced as samples to study the evolutionary pattern of the THMC behavior of reinforced clays. Samples with designed curing times (1, 3, 7, 28, and 90 days) will be trimmed to the appropriate size and utilized in a series of mechanical tests. Furthermore, the other portion of the samples, which is pre-installed with sensors, is used to monitor the development in internal temperature, volumetric water content, suction, and electrical conductivity for 90 days. The results showed that the content of cement and curing time have a significant influence on the THMC behavior of reinforced clay. Meanwhile, the results indicate a strong coupling of the THMC behavior of clays reinforced by cement. The results will be of critical assistance in gaining advanced knowledge into the evolutionary pattern in the THMC behavior of reinforced clays as well as making a contribution to optimizing the stability, cost-effectiveness, and durability of the design of reinforced clays. [ABSTRACT FROM AUTHOR]

The world today, is plagued by several environmental problems including air pollution and global warming. These aforementioned environmental problems are prominently associated with the consumption of natural resources in manners that have proven to be unsustainable. The construction industry has been seen to play a major role in contributing to the natural resources consumption and environmental problems, at large. Cement production brings about the emission of toxic gases that pollute the atmosphere, thereby promoting these environmental problems. Consequently, concrete technology findings have been directed toward realizing alternative sustainable materials for utilization in the construction industry. Seashell waste has proven promising in the partial replacement of cement in concrete. This study had carried out experimental investigations on senilia senilis shell as a partial cement replacement material in concrete production. The senilia senilis shell was crushed into senilia senilis powder (SSP), processed, and utilized to partially replace cement at 10%, 20%, 30%, 40%, 50%, and 60% in concrete. Fineness, Initial and final setting, and specific gravity tests were carried out on seashell powder to ascertain its suitability for cement replacement. Physical and mechanical tests were carried out on the concrete samples produced. The mechanical properties of the various concrete specimens were also analyzed in this study. Also, the elemental composition and morphological analysis of the SSP and the various concrete specimens were examined in this study with the use of a Scanning Electron Microscope (SEM) and energy-dispersive X-ray (EDX). The results of this study indicate that SSP concrete at 10% to 20% replacement of cement, can be utilized for various mix ratios in the construction industry. [ABSTRACT FROM AUTHOR]

The structural design standards, particularly in concrete technology, heavily rely on the mechanical attributes of concrete. Utilizing dependable predictive models for these properties can minimize the need for extensive laboratory testing, evaluations, and experiments to acquire essential design data, thereby conserving time and resources. Metakaolin (MK) is frequently incorporated as an alternative to Portland cement in the production of sustainable concrete, owing to its technical advantages and positive environmental impact, aligning with the United Nations Sustainable Development Goals (UNSDGs) aimed at achieving net-zero objectives. However, this research presents a comparative study between eight (8) ML classification techniques namely, gradient boosting (GB), CN2, naïve bayes (NB), support vector machine (SVM), stochastic gradient descent (SGD), k-nearest neighbor (KNN), Tree and random forest (RF) to estimate the impact of adding metakaolin to concrete on its flexural strength considering mixture components contents and concrete age. The collected data entries for the prediction of the flexural strength (Ft) containing the following concrete components; contentof cement (C), content of metakaolin (MK), content of water (W), content of fine aggregates (FAg), content of coarse aggregates (CAg), content of super-plasticizer (P), and the concrete curing age at testing (Age) were partitioned into 80% and 20% for training and validation sets respectively. At the end of the model protocol, it was found that the GB, SVM, and KNN models which produced an average MSE value of zero (0) showed their decisive ability to predict the flexural strength of the metakaolin (MK) mixed concrete (Ft). This outcome agrees with the previous reports in the literatures; however the work of Shah et al. happens to be the closest in terms of concrete components used in the production of the mixes and the application of machine learning techniques. It was found that the present research work's models outperformed those presented by Shah et al. Hence the decisive models reported in this research paper show potentials to be applied in the design and production of MK concrete with optimal flexural strength. [ABSTRACT FROM AUTHOR]

This research aims to produce green cement, as an alternative to traditional cement, with outstanding performance. Five alkali-activated cement pastes were fabricated based on NaOH-activation of slag (GGBFS), bypass (B), and/or silica fume (S). Codes of five pastes are C, C-20B, C-30B, C-10B10S, and C-20B10S, as C is the control paste containing 100% slag. The compressive strength of the fabricated pastes was measured at different curing regimes: Conventional curing for 3 months and autoclave curing at 4 bar/153◦C, 7 bar/178◦C, and 10 bar/198◦C for 4 h. XRD, TGA/DTG, SEM/EDX, and BET/BJH techniques were utilized to clarify the phase development, morphological and texture features of the formed alkali-activated composite pastes. Besides, the removal capacity of some pastes for methylene blue and indigo-carmine dyes from aqueous media was evaluated. The results confirmed that C and C10B10S (80%GGBFS + 10%B + 10%S) pastes have significant mechanical properties and distinctive meso-porosity that can remove both anionic and cationic dyes. [ABSTRACT FROM AUTHOR]

Beryllium metal is used as neutron moderator and reflector or multiplier in certain types of fission or fusion reactors. Dismantling of these reactors will produce radioactive beryllium waste, classified as low- or intermediate-level waste, that will need to be stabilised and solidified before being sent to disposal. The cementation process is under consideration because it may offer a good compromise between simplicity of implementation, cost, and quality of the final cemented wasteform. Nevertheless, knowledge of the corrosion behaviour of Be metal in a cement-based matrix is still limited, partly due to the high toxicity of Be that complicates testing. This study thus investigates Be corrosion in cement suspensions using potentiometry, voltammetry, and electrochemical impedance spectroscopy. Among the five different investigated systems (Portland cement blended without or with 40 wt.% silica fume, calcium sulfoaluminate clinker blended without or with 15% anhydrite, and calcium aluminate cement), Portland cement blended with 40% silica fume and calcium sulfoaluminate cement comprising 15% anhydrite are the most effective in mitigating beryllium corrosion. They allow reduction in the corrosion current by factors of 4 and 50, respectively, as compared to Portland cement. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Materials and Methods Results Conclusions Clinical Significance This study proposes an updated method for the film thickness of 21 resin composites used as cements.A load of 30 N was subjected to two glass plates stacked on a heated base to simulate clinically relevant pressure and temperature during the seating of inlays/onlays/veneers. The axial position of the actuator was recorded before and after placing 22.15 mm3 of resin composite between the glass slides. The difference between the two measurements was calculated for each specimen. A total of 18 condensable restoratives, 1 injectable restorative, and 2 resin cements were tested, 5 specimens each (n = 5, N = 105). One‐way ANOVA was performed for both variables and Games‐Howell post hoc test was used for pairwise comparisons.The film thickness range was 6–200 μm, with the lowest values for restorative composites (AP‐X, Z250, and Herculite XRV Incisal LT with 6–8 μm), followed by Gradia Direct (25 μm) and flowable/injectable composite resins, including designated cements (15–27 μm). Inspiro, Ultradent Transcend Universal, and ENA Hri dentin stood below 50 μm (range 28–49 μm). The other materials (range 81–200 μm) cannot be recommended for thermo‐modified cementation.The initial viscosity of restorative composites is not an indication of the film thickness when used for thermo‐modified cementation. There is a wide choice of appropriate materials available on the market.Some restorative composites are able to generate very thin films and can be used as cement with numerous advantages when compared to designated flowable or dual‐cure cements. [ABSTRACT FROM AUTHOR]

While ultra-high performance concrete (UHPC) offers numerous advantages, it also presents specific challenges, primarily due to its high cost and excessive cement content, which can pose sustainability concerns. To address this challenge, this study aims to develop cost-effective and sustainable UHPC mixtures by incorporating ground granulated blast furnace slag (GGBFS) and limestone powder (LP) as partial replacements for portland cement. Eight fiber-reinforced UHPC mixtures were investigated, with a water-to-cementitious materials (w/cm) ratio of 0.15. In four of the UHPC mixtures, 25% of the cement was replaced with GGBFS, and further, LP was added as a mineral filler, partially substituting up to 20% of the cement. In the remaining four mixtures, cement was replaced with only LP up to 20% (without GGBFS). The 28-day compressive strength of the UHPC mixture with 25% GGBFS and 20% LP was 149 MPa, 3.50% lower than the mixture without GGBFS. Its 28-day flexural strength decreased by 30%. Increasing LP replacement reduced drying and autogenous shrinkage, with a 29% shrinkage reduction at 20% LP replacement. Moreover, UHPC mixtures with GGBFS exhibited lower shrinkage compared to those without GGBFS for all LP replacements up to 20%. For evaluating the sustainability of UHPC mixtures, the cement composition index (CCI) and clinker to cement ratio (CCR) were determined. For 20% LP replacement with 25% GGBFS, CCI was 3.6 and the CCR was 0.5, 38% decrease from the global clinker to cement ratio. Overall, 20% LP replacement UHPC mixtures with and without GGBFS can produce UHPC class performance and reduce the environmental impact. [ABSTRACT FROM AUTHOR]

Aims: Careful selection of materials and resin cement shade can minimize color changes in laminate veneers. This study aimed to evaluate the influence of two ceramic material types, lithium disilicate glass–ceramic material (Ivoclar, Schaan/Liechtenstein; IPS e.max), computer aided design (CAD) and IPS e.max Press, and four different resin cement shades on color changes in lithium disilicate ceramic laminate veneers. Methods: Forty extracted human maxillary first premolars were prepared to receive a laminate veneer. Optical scanning and digital designing were used to prepare 20 IPS e.max CAD and 20 IPS e.max Press veneer samples. These samples were divided into four groups based on resin cement shade and material: Group CAD A1 : (IPS e.max CAD with A1 cement shade), Group CAD T : (IPS e.max CAD with translucent cement shade), Group CAD M : (IPS e.max CAD with milky bright cement shade), Group CAD B1 : (IPS e.max CAD with B1 cement shade) and the same divisions for IPS e.max Press. Before cementation, color measurements were obtained using precision colorimeter NR110. After cementation, the ∆E (color change) value was recorded and tabulated. One‐way analysis of variance (ANOVA) and Duncan's post hoc test were used to evaluate the influence of ceramic material types and cement shade on ∆E. Results: There were significant differences between the IPS e.max CAD and e.max Press veneers for the four tested cement shades. The highest color change was observed in press M veneers (8.84 ± 0.63931) while the lowest color change was observed in CAD M veneers (0.5 ± 0.16371). There were significant differences in color change based on cement shade, with B1 showing the greatest change (8.84 ± 0.47440 for Press veneers and 2.3 ± 0.11992 for CAD veneers). Conclusions: Different shades of resin cements and different manufacturing techniques produce different levels of color changes therefore careful selection of materials and cement shade can minimize color changes in laminate veneers. [ABSTRACT FROM AUTHOR]

Production of Portland cement consumes a huge amount of silica mineral. The present work aims to introduce desert sand to replace the natural mineral to achieve green manufacturing of silicate cement clinker, as well as further decreasing the synthesis temperature and increasing the production efficiency. The effects of desert sand, industrial quartz and high‐purity quartz as raw materials, and Al2O3 and Fe2O3 as additives on phase transformation and microstructure of calcium silicate powder were comparably investigated using X‐ray diffractometer, differential scanning calorimeter, and scanning electron microscopy. Results show that the main phases of all samples with different raw materials and additives were 3CaO·SiO2 (C3S) and 2CaO·SiO2 (C2S). In which, the samples prepared using desert sand had the lowest phase transformation temperature for C2S and C3S. When adding Al2O3 and Fe2O3, the phase transformation temperatures of C2S and C3S further decreased, which were 1032.5°C and 1270.9°C, respectively, meanwhile phase content reached the maximum (C2S of 65.6 wt.% and C3S of 61.2 wt.%). In addition, the most uniformly and finely distributed crystalline phases formed at an optimal calcination temperature of 1350°C. This is beneficial for reducing production costs, saving mineral resources, and promoting the sustainable development of the cement industry. [ABSTRACT FROM AUTHOR]

AbstractIn this study, the life cycle and performance of normal concrete containing 35% limestone and 2% gypsum made in different ratios of water to binder (w/b) were examined. Its cost and CO2 emissions were found to be 13% and 35% lower compared to the control concrete. However, because of the greater replacement of cement with limestone filler, there is a reduction in its workability, the development of heat and strength, and the penetration resistance of water and chloride ions, especially in the early ages. The addition of gypsum marginally improved these concrete properties, but its quantity should be limited to 2% by weight of the binder. The use of gypsum beyond this limit led to a significant decrease in the properties of concrete. Anorthite, a calcium aluminosilicate mineral, was found in this concrete, and its fractured morphology was found to be more occupied with unreacted angular limestone particles. This low-carbon concrete showed an improvement in compressive strength with decreasing w/b ratios. The limestone reserve in India is abundant and spread evenly across its length and depth, and its use as the main replacement for cement in normal strength mixes would greatly reduce the impact of CO2 on the environment. [ABSTRACT FROM AUTHOR]

A tetracalcium phosphate/monetite/calcium sulfate hemihydrate powder cement mixture (CAS) in the form of a paste was used as a socket preservative to prevent alveolar ridge resorption after the extraction of the second premolar tooth in the mandible of a pig model. During the post-surgery period, the animals were monitored daily. No signs of inflammation, infection, or other complications were observed in the defect site for six months. Six months after surgery, the mandible defects in pigs were evaluated using macroscopic, histological, and radiological techniques. Treatment of the extraction sites with CAS biocement resulted in the uniform filling of the defects with alveolar bone tissue, characterized by a relatively smooth and homogeneous gum surface with no visible biocement residues. The formation of new bone tissue with osteoblasts, osteocytes, and mineralized matrices was confirmed. The results showed the similar morphology, thickness, and complete integration of the newly formed bone with the surrounding tissue. CAS biocement could be an effective material to prevent alveolar bone reduction as well as soft tissue loss and could support dental implant placement with long-term functionality. [ABSTRACT FROM AUTHOR]

The raw materials of cement contain radioactive elements that come from natural sources. Members of the decay chains of uranium, thorium, and potassium radioisotope 40K are the primary sources of this radioactivity. The natural radionuclide concentration levels in cement differ greatly depending on different geographic areas. To estimate the radionuclides concentration in cement specimens from twelve diverse Pakistani companies, gamma-ray spectroscopy analysis was used in the study. 226Ra, 232Th, and 40K had activity concentration levels ranging from 18.08 to 43.18 Bq/kg, 16.73 to 23.53 Bq/kg, and 14.24 to 315.22 Bq/kg, respectively. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) threshold for the 226Ra was surpassed by five of the studied samples. The indoor and outdoor dose rates as well as different radiological health hazard indices were also examined. The Indoor Absorbed Dosage (Din) for some of the samples exceeded the permissible limit. These samples also had a high Indoor Effective Lifetime Cancer Risk (ELCR) factor, which makes them unsafe for interior construction purposes. The outdoor dosages as well as the hazard indices were well within the permitted ranges. The outdoor ELCR factor is low for all the cement brands, which makes them safe for exterior construction purposes. The findings were compared with published data from other countries around the globe. Finally, a thorough statistical analysis was performed and Pearson's Correlation Coefficient (r) exhibited a very strong correlation between the different outdoor and indoor radiological health hazard indices. [ABSTRACT FROM AUTHOR]

The acrylic polymer composites in this study are made up of various weight ratios of cement or silica nanoparticles (1, 3, 5, and 10 wt%) using the casting method. The effects of doping ratio/type on mechanical, dielectric, thermal, and hydrophobic properties were investigated. Acrylic polymer composites containing 5 wt% cement or silica nanoparticles had the lowest abrasion wear rates and the highest shore-D hardness and impact strength. The increase in the inclusion of cement or silica nanoparticles enhanced surface roughness, water contact angle (WCA), and thermal insulation. Acrylic/cement composites demonstrated higher mechanical, electrical, and thermal insulation properties than acrylic/silica composites because of their lower particle size and their low thermal/electrical conductivity. Furthermore, to improve the surface hydrophobic characteristics of acrylic composites, the surface was treated with a dielectric barrier discharge (DBD) plasma jet. The DBD plasma jet treatment significantly enhanced the hydrophobicity of acrylic polymer composites. For example, the WCA of acrylic composites containing 5 wt% silica or cement nanoparticles increased from 35.3° to 55° and 44.7° to 73°, respectively, by plasma treatment performed at an Ar flow rate of 5 L/min and for an exposure interval of 25 s. The DBD plasma jet treatment is an excellent and inexpensive technique for improving the hydrophobic properties of acrylic polymer composites. These findings offer important perspectives on the development of materials coating for technical applications. [ABSTRACT FROM AUTHOR]

Polycarboxylate ether (PCE) superplasticisers have been widely used in cement formulations. However, it is not until recently that several studies have analysed the relationship between the properties and the molecular structure. In the present work, PCEs with different side chain lengths and charge densities synthesised through free radical copolymerisation are used to analyse the effect they have on the hydration of ordinary Portland cement (OPC). It was found that the addition method of these PCEs to the OPC significantly affects the hydration kinetics of the cement paste. When PCEs are added through the direct addition method, a linear dependency between the retardation of hydration and the microstructure of the used PCEs is observed. On the contrary, when PCEs are added through the delayed addition method (PCEs are added to the cement paste 5 min after water), no retardation in hydration is observed, but the rate of hydration is reduced. [ABSTRACT FROM AUTHOR]

The permeability of cementitious soils is substantially controlled by the permeability of the soil itself, the dosage of binder, the water-to-binder ratio, and other factors. This study employed metakaolin as the additive to enhance underground engineering construction's economic benefit since it could improve the impermeability of cement-stabilized soils and replace cement partly. A series of indoor permeability tests on cement- and metakaolin-stabilized fine sandy soils (CMSFSSs) with different cement-to-metakaolin ratios, water-to-binder (the mixture of cement and metakaolin) ratios, total binder contents, and curing times were conducted. The influences of these factors on the impermeability of CMSFSSs were investigated. Their impermeability improvement mechanism at the microscale was explored by Scanning Electron Microscopy and Mercury Injection Porosimeter tests. The empirical permeability coefficient prediction formulas about these influence factors, compressive strength, and porosity were discussed. The results showed that the best impermeability of CMSFSSs was achieved when the cement-to-metakaolin ratio was 5:1, saving 1/6 cement consumption. This ratio did not vary with the total binder content. The permeability coefficient of CMSFSSs increased nonlinearly with the water-to-binder ratio but decreased rapidly at first and then slowly with the increase of total binder content and curing time. The optional water-to-binder ratio should be less than 0.6 if both their liquidity and impermeability requirements were met together. The total binder content for fine sandy soil stabilization should be less than 15% since it was not more reliable to improve the impermeability of fine sandy soils by using excessive binder in terms of economic benefits. The hydrated gels in CMSFSSs formed rapidly at the early curing time. The calcium hydroxide formed by cement hydration disappeared over the curing time. The internal pore volume and sizes in CMSFSSs decreased over the curing time, resulting in worse and worse connectivity. All of them proved the contribution of metakaolin to cement-stabilized soil's impermeability improvement. Six empirical formulas for the permeability coefficient of binder-stabilized soils were summarized regarding the water-to-binder ratio, total binder content, curing time, unconfined compressive strength, and porosity. The results of this study provide theoretical and technical references for improving the impermeability of binder-stabilized soils. [ABSTRACT FROM AUTHOR]

This study explores the fabrication of cement-based sensors blended with supplementary cementitious materials (SCM) using carbonation curing. The effects of SCM types (i.e. fly ash or slag) and curing conditions on degree of carbon dioxide uptake, compressive strength, electrical conductivity and piezoresistive sensing capability were systematically examined. The results indicate that the inclusion of fly ash or slag enhances the degree of carbon dioxide uptake. However, it is also found that the excessive carbonation curing negatively affects compressive strength. Electrical resistivity is increased after carbonation curing due to carbonation-induced hydrate formation disrupting carbon nanotube-based conductive networks. The piezoresistive sensing capability is influenced by binder types and curing conditions, with higher sensitivity observed in samples blended with fly ash. [ABSTRACT FROM AUTHOR]

The characteristics of shotcrete can lead to significant shrinkage deformation, presenting potential threats to tunnel structure safety. To research this concern, in this study the effects of three accelerators on the volume stability of cement paste, cement mortar and concrete were investigated. The correlation equations of the shrinkage deformation of cement paste, cement mortar and concrete were established, and the drying shrinkage prediction model of cement mortar with accelerator was constructed by combining the ACI 209 model and the GL2000 model. Findings from this study show that the liquid alkali accelerator AR had the greatest autogenous shrinkage and drying shrinkage, with the highest mass loss under drying conditions. The study demonstrated that there exists a good linear relationship between the shrinkage deformation of cement paste, cement mortar and concrete with accelerator. Finally, the proposed prediction model for drying shrinkage of cement mortar exhibits strong predictive capabilities. [ABSTRACT FROM AUTHOR]

This study developed an energy-efficient, sustainable, and economical method for capturing carbon dioxide using landfilled coal fly ash. The innovative approach processes captured carbon dioxide with supplementary additives and alkali activators to produce a new class of hydraulic cement. A total of eight cement formulations incorporating varying proportions of landfilled coal fly ash, calcium-containing industrial byproducts, and alkali activators were produced and experimentally tested. The study achieved significant CO₂ uptakes, reaching up to 8.35% by weight of the raw materials. Up to 99.98% immobilization efficiency of heavy metal (copper) was recorded along with a significant increase in the total dissolved solids and conductivity. FTIR spectroscopy confirmed CO₂ incorporation with notable peaks at 1400 cm− 1 and 1063 cm− 1, indicating carbonate species. SEM and EDS analyses revealed varied morphologies, with dense, interconnected particle networks in some of the cement formulations. Compressive strength tests showed all formulations exceeded the EPA's minimum requirement of 0.34 MPa, with the highest strength reaching 38 MPa at 28 days. The findings of this study point to the viability of the production of mechanochemically processed hydraulic cements in CO₂ environment with effective carbon sequestration capability, marked heavy metals immobilization characteristics, and enhanced physical and mechanical attributes. [ABSTRACT FROM AUTHOR]

In the frame of the Venezia2021 project the private 'Byzantine house' designed by Giuseppe Torres in 1905 was chosen as the emblematic architectural site which marks Venice's transition towards modernity, requiring study of its conservation in the lagoon environment of the city of Venice. In conjunction with the definition of a specific Path of Knowledge of the ground floor, a series of stone and lithoid materials as well as their related deterioration products from the interior rooms were sampled for analysis. The investigations covered a wide range of materials (plasters, mortars, natural and artificial stones, bricks, glass and finishings). They were carried out by means of a multi-analytical approach comprising SEM-EDX and optical microscopy; XRPD; XRF, ion chromatography; and Raman and infrared (FTIR) spectroscopies. The stones identified are linked to the Venetian architectural tradition (Euganean trachyte and Istrian stone). The sands in the mortars are mainly of regional origin and the glass is compatible with traditional Venetian (Murano) recipes. Of particular interest is the presence of an intonachino charged with ground fluorite. The deterioration products are linked to the extensive and intense phenomenon of capillary rising damp and efflorescence deposition induced by the lagoon environment. [ABSTRACT FROM AUTHOR]

In this research, a series of consolidated drained compression triaxial tests were carried out to investigate the mechanical performance of Babolsar sand. Next, the parameters such as cement zeolite substitution percentage, cement content, and curing time were determined. The results revealed significant mechanical strength of specimens by replacing zeolite up to 35% compared with cemented sand mixtures for all ranges of cement percentages. Also, the samples showed more ductile behaviour due to increasing strains at failure. Increasing the zeolite substitution by up to 35% generated shearing band failure. However, exceeding the 35% substitution, the barrelling shear mode was predominant. All samples were compressed initially until reaching a point of instant zero dilation and then dilated until the end of the tests. The dilation tendency was higher in zeolite percentages up to 35%. Moreover, increasing the cement content enhanced the dilation of specimens due to hardening and interlocking cement and sand with zeolite. Finally, microstructure analysis results showed the Si/Ca ratio as a key index to approximate triaxial shear strength development. [ABSTRACT FROM AUTHOR]

Heavy-weight concrete (HWC) is a widely adopted radiation shielding material in the nuclear industry. In this study, two kinds of high-density aggregate, namely, iron sand (IS) and steel slag coarse aggregate (SSCA), were adopted to fully replace river sand and natural coarse aggregate, respectively, producing ultra-heavy-weight concrete (UHWC) with a unit weight >3800 kg/m3, to ensure excellent radiation shielding performance. However, IS and SSCA seriously impaired the passing ability of UHWC as the cement paste could not hold the IS and SSCA as firmly as natural aggregates, owing to their high density. To overcome this, the rheology of UHWC should be optimised by partially replacing the cement with superfine silica fume (SSF) and using a suitable amount of superplasticiser (SP) to enhance the wet packing density (WPD). A total of 28 UHWC mixes with different replacement ratios of SSF and different SP dosages were tested for segregation width, flowability, L-box passing ability, unit weight and WPD. Results revealed that incorporating an appropriate quantity of SSF and SP improved the WPD of UHWC, resulting in improved segregation resistance, enhanced flowability, increased passing ability and a higher unit weight. Lastly, there is a positive correlation between flowability, passing ability and WPD. [ABSTRACT FROM AUTHOR]

An experimental programme was conducted to observe, non-destructively, the influence of aggregate particle size and low water/cement (w/c) ratios on alkali–silica reaction (ASR) in concrete using micro-computed tomography scanning. The results were analysed using a model developed as part of a previous study. ASR expansion and cracking was observed to increase to strain levels of around 0.010 with a decrease in particle diameter up to a 'pessimum' diameter of 1–2 mm. Below the pessimum diameter, expansion was low: around 0.001 strain. Analysis using the previously developed model clearly illustrated a transition from above the pessimum diameter, where ASR was the main process occurring, to below this size, where a pozzolanic reaction dominated. ASR expansion increased with a decrease in the w/c ratio, reaching strains of around 0.015. The model indicated that this is fundamentally a result of extended periods of restraint of ASR gel around aggregates, ultimately ending in much greater expansion when fracture eventually occurred. Additionally, cracking of aggregate coincided with an accelerated rate of expansion in mixes with w/c ratios below 0.6. [ABSTRACT FROM AUTHOR]

There is few research about the liquid drainage in the sample compaction of asphalt emulsion mixtures (AEMs). In this study, the liquid drainage of AEMs with cement is quantitatively measured. The air voids, indirect tensile strength, and moisture susceptibility of cured samples are investigated to explain the effect of liquid drainage. The test results indicate that the liquid drainage percentages of samples are influenced by emulsion content, cement content, compaction methods, and mold types. Liquid drainage is beneficial in terms of decreasing air voids and improving moisture resistance. However, these positive effects can be negligible when using a perforated mold. The drained liquid consists of free water and a small amount of asphalt droplets. The liquid drainage does not mean that the total air voids in samples are in a water saturation state. The liquid drainage in laboratory compaction cannot reflect the real water movement in construction compaction. [ABSTRACT FROM AUTHOR]

To solve the problem of the proportional design of cement concrete prepared by using manufactured sand instead of river sand, a new method of manufactured sand concrete mix design was proposed with the dense packing of coarse and fine aggregate. Compared with the original sieving method, the stone powder in the manufactured sand can be regarded as cementitious materials for slurry. With the proposed mix design method, there is no need to separate from the manufactured sand. This dense packing method considers the actual situation that both the manufactured sand and coarse aggregate are mechanically prepared, and all the aggregates can be unified in proportion. The composition ratio of aggregate with particle size greater than 0.075 mm is designed by the maximum density theory, and the rest of the part (below 0.075 mm) is treated as a cementitious material. As a parameter of the maximum density theory, the Fuller index of 0.45 was verified when the calculation values agreed well with the test results. With the proposed mix ratio design method, the different grades C30, C40, and C50 of manufactured sand concrete were designed. Furthermore, the properties such as workability and mechanical properties for the designed manufactured sand concrete were investigated to determine the applicability of the proposed mix design method. The test results show that the workability, uniformity, and strength of the manufactured sand concrete were better than the original mix ratio design method, which verifies the operability and reasonableness of the proposed mix ratio design method. [ABSTRACT FROM AUTHOR]