Cement-based Materials Research Articles

Machine Learning Driven Fluidity and Rheological Properties Prediction of Fresh Cement-Based Materials

Controlling workability during the design stage of cement-based material mix ratios is a highly time-consuming and labor-intensive task. Applying artificial intelligence (AI) methods to predict and optimize the workability of cement-based materials can significantly enhance the efficiency of mix design. In this study, experimental testing was conducted to create a dataset of 233 samples, including fluidity, dynamic yield stress, and plastic viscosity of cement-based materials. The proportions of cement, fly ash (FA), silica fume (SF), water, superplasticizer (SP), hydroxypropyl methylcellulose (HPMC), and sand were selected as inputs. Machine learning (ML) methods were employed to establish predictive models for these three early workability indicators. To improve prediction capability, optimized hybrid models, such as Particle Swarm Optimization (PSO)-based CatBoost and XGBoost, were adopted. Furthermore, the influence of individual input variables on each workability indicator of the cement-based material was examined using Shapley Additive Explanations (SHAP) and Partial Dependence Plot (PDP) analyses. This study provides a novel reference for achieving rapid and accurate control of cement-based material workability.

Study on Mechanical Properties of Fiber-reinforced Cement-based Materials

Fiber reinforced cement-based materials are used to add various kinds of fibers to ordinary cement-based materials to improve their tensile strength, compressive strength, shear strength, flexural strength, flexural strength and impact resistance. There are many kinds of fiber, including steel fiber, carbon fiber, glass fiber, polypropylene fiber and basalt fiber, etc. The type, shape, content and length-diameter ratio of fiber will affect the performance of cement-based materials. In this paper, the research status of steel fiber, polypropylene fiber and basalt fiber on cement-based materials is reviewed, and the application of fiber reinforced cement-based materials is prospected.

Effects of amino alcohols-intercalated MgAl-LDH nanocomposites on the properties of sulfoaluminate cement-based materials

Sulfoaluminate cement-based materials (SCBMs) have low mechanical properties in the early stages when they are used in grouting reinforcement engineering. The mechanical properties of cement-based materials can be improved by nanotechnology. Hydrotalcite is a layered anionic clay with adjustable interlayer anions and nanometer spacing. To date, the effect of amino alcohols (ethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA))-intercalated MgAl-layered double hydroxides (LDH) nanocomposites (denoted as MgAl-LDH-TEA, MgAl-LDH-DEA, and MgAl-LDH-MEA) on the properties of SCBMs have not been studied. Herein, we demonstrate that intercalated MgAl-LDH exhibit a decrease in crystallinity, an increase in particle size, and improved early mechanical properties compared to unmodified LDHs. MgAl-LDH modified by TEA, DEA, and MEA all have a nucleation effect and provide nucleation sites for ettringite. Simultaneously, the intercalated hydrotalcite can release higher concentrations of magnesium ions into the slurry, forming a magnesium-containing ettringite phase and accelerating the hydration of SCBMs. Modified MgAl-LDH can also release amino alcohols, affecting the hydration process of the paste. The modified LDHs affect the hydration and compressive strength of SCBMs owing to the combined action of the nucleation of LDHs and the release of magnesium ions and amino alcohols compounds.

Numerical simulation of strengthening/deterioration and damage development of cementitious materials under sulfate attack environment

Cementitious materials exposed to sulfate environments often suffer from the combined effects of external sulfate attack and dry wet cycling. In order to predict the long-term performance of cement-based materials in sulfur rich environments, this paper aims to establish a numerical model that can reasonably characterize the degradation process of cementitious materials in sulfate environments. Using this model, we can address durability problems common to cementitious materials in real sulphate environments, such as determining the degree of corrosion, predicting the durability life of materials, and calculating the time to failure. The model consists of three parts: transportation, chemical reactions, and material damage. We establish the degradation model for cement-based materials in sulfate environments by considering ion diffusion, water convection, chemical reactions, accumulation of corrosion products, and the development of material strengthening/degradation. Compared with existing sulfate corrosion models, this model not only considers ettringite, but also takes into account the volume changes of gypsum formation, calcium leaching, and salt crystallization precipitation, which can more reasonably simulate the sulfate corrosion process in real environments. The model can reasonably simulate the distribution pattern of ion concentration, hydration products and corrosion products in the cementitious material, and on this basis calculate the porosity of the cementitious material. In order to make the simulation results more applicable to experimental and non-destructive testing results, the model uses easily obtainable relative dynamic elastic modulus to evaluate the degree of material strengthening/degradation and predict the durability life of the material.

Sustainable Biobased Hydrogel as an Alternative Air-Entrainment Agent in Cement-Based Materials

Sustainable Biobased Hydrogel as an Alternative Air-Entrainment Agent in Cement-Based Materials

An investigation of the physic-mechanical properties of the expanded perlite mortars with thermal-activated concrete waste and microencapsulated paraffin

In the transition to zero waste and sustainable development, it becomes essential to use phase change materials and recycled cement in construction projects to improve energy efficiency and encourage sustainable building practices. The primary goal of this study is to determine how the properties of expanded perlite mortars are affected when Portland cement is partially replaced with recycled cement, produced by thermally treating concrete waste at 550˚C. Recycled cement substituted Portland cement in various percentages (10%, 30%, and 50%). Also, microencapsulated phase change material (m-PCM) was incorporated into the mortar in a proportion of 2 wt.% and 5 wt.%. Cement-based mortars with a 1:3 aggregate volume ratio have been developed for evaluation. The mortars were analyzed in terms of mechanical strength (flexural and compressive), water absorption, thermal properties, differential scanning calorimetry, and microstructure. The experimental results revealed a decrease in mechanical strength values when Portland cement is substituted by recycled cement, regardless of percentage. Recycled cement in proportion of 30% positively influenced the water absorption. The thermal conductivity of reference mortar was higher than that of 30% recycled cement. The reference mortar's specific thermal conductivity values were 0.466 W/(m·K) at 25°C, 0.525 W/(m·K) at 30°C, and 0.589 W/(m·K) at 35°C. On the other hand, the mortar containing 30% recycled cement exhibited much lower heat conductivity throughout these temperatures, suggesting superior insulating qualities. DSC analysis verified that adding m-PCM to the mortars increased their thermal storage capacity, which is essential for raising the energy efficiency of building materials. Nevertheless, the mechanical strength decreased as m-PCM was added. Despite decreases, all mortars satisfied the SR EN 998–1 standard's CS IV classification for interior plaster applications, which is based on compressive strength requirements. Overall, this study shows how using m-PCM and recycled materials can improve the performance of cement-based materials.

Influence of limestone powder particle size on the sulfate resistance of cement-based materials under the coupling effect of time-varying temperature and sulfate attack

Influence of limestone powder particle size on the sulfate resistance of cement-based materials under the coupling effect of time-varying temperature and sulfate attack

Influence of the graphene oxide-coated steel fiber on the microstructure optimization of UHPC

Benefiting from its superior mechanical properties, large specific surface area and abundant oxygen-containing functional groups, graphene oxide (GO) can generate nucleation and pore-infilling effects to optimize the microstructure of the cementitious composites, thus reinforcing the mechanical performance and durability of cement-based materials. However, due to the dispersion issues and relatively high cost, the widespread use of GO in the cement industry has not yet been realized. In the present study, we applied three different methods to coat industrial GO nanosheets on the steel fiber’s surface and reinforce the UHPC microstructure. The proposed coating method effectively disperses GO within the ultra-high-performance concrete (UHPC) matrix and targets its enhancement effects on the interfacial transition zone (ITZ), which has the weakest pore structure in UHPC. The result presents that the three-step dip method of GO coating on the steel fiber demonstrates higher effectiveness in reinforcing the microstructure of UHPC, the porosity of the matrix is 1.88 %, with a relative decrease of 37.1 ∼ 60.3 %. In addition, the average distance of ITZ after GO enhanced UHPC is about 3.7 µm, about 37.3 %-68.1 % shorter, and the ITZ porosity is 3.8 %, which is 15.6 %-65.5 % lower. With the assistance of the metal intrusion technique, backscattered electron characterization and deep learning-based analysis, the pore structure features of UHPC were extracted with a classification recognition accuracy of 88.5 %, and the pore intrusion volume inside the characteristic region of the UHPC matrix increased by 1.89–2.14 times. The extraction characteristics illustrated that the GO strengthening on steel fibers was more effective in ITZ, with an optimization efficiency of about 8.1 % higher than in other regions. We expect that the findings of this study could provide deep insights into GO modification for cementitious composite reinforcement applications and open new pathways for affordable alternatives to nano-enhanced composites.

Limestone Calcined Clay-based Engineered Cementitious Composites (LC3-ECC) with Recycled Sand: Macro Performance and Micro Mechanism

Limestone calcined clay cement (LC3) contributes to the development of sustainable cement-based materials. In this study, LC3 was combined with fly ash (FA) and recycled sands (RS) to develop engineered cementitious composites (ECC). Three FA/LC3 ratios (1, 1.5, and 2) and three RS particle sizes (0.15-1.18mm, 0.15-2.36mm, and 0.15-4.75mm) were studied. Compared to ordinary Portland cement (OPC)-based paste, the LC3 substitution resulted in higher hydration heat and hydration degree, forming more hydration products. Although LC3 substitution produced a slightly lower compressive strength, a more robust tensile strain-hardening behavior than OPC-based ECC was achieved. The increasing FA/LC3 ratios gradually reduced compressive strength, tensile strength, and crack width. The multiple cracking behavior with controlled widths of LC3-based ECC was found to be more stable, which could be traced to the superior properties of fiber/matrix interfacial transition zone. In addition, utilizing RS as fine aggregates with various particle sizes could achieve an ultra-high tensile strain capacity exceeding 8% for LC3-based ECC, thereby enhancing its utilization efficiency. Furthermore, the utilization of LC3 resulted in 28.6-47.1% and 6.6-22.0% reductions in carbon emission and embodied energy, respectively. The combination of LC3 and RS holds a promising approach to developing sustainable ECC with desirable mechanical performance.

Microstructure evolution process and multi-scale deterioration mechanism model of graphite tailings cement-based materials subjected to high temperature

This manuscript investigated the thermal stability, crystal reconstruction and microstructure evolution of graphite tailing cement mortar subjected to high temperature. Simultaneously, a computational model for heat transfer and degradation considering chemical transformations had been developed by combining multiscale mechanics with the laws of thermodynamics. The results show that 20% graphite tailings can increase the tobermorite crystal content under high temperature and inhibit its transformation into disordered form. Furthermore, the dormant active SiOx in graphite tailing is gradually activated under the action of high temperature, which catalyzes and induces the formation of more belite crystal in graphite tailing cement mortar. Additionally, 40% graphite tailing can promote the generation of anorthite by the induction of high temperature. Finally, a new multi-scale model considering the chemical transformation is established to calculate the high-temperature degradation process of graphite tailing cement mortar.

Development and performance evaluation of ultra-lightweight geopolymer foam insulation material

The preparation technology for new ultra-lightweight geopolymer insulation materials (ULGIM) has been developed based on the principle of alkaline activation, and ULGIM for building walls have been obtained. It has improved the problem of traditional inorganic foam insulation material that cannot balance density, insulation performance, mechanical performance and environmental performance. The composition of supplementary cementitious materials, the mass ratio between each component, and water to binder ratio (w/b) were used to analyze the thermal conductivity, dry density, volumetric water absorption, compressive strength, average pore diameter, and porosity of ULGIM. The life cycle assessment (LCA) method was employed to assess the environmental impact of ULGIM production. The test results showed that ULGIM achieved a dry density and thermal conductivity of ULGIM only 181.17 kg/m3 and 0.0427 W/(m·K), respectively, and the optimal compressive strength was 0.72 MPa at 7 d. ULGIM exhibited superior compressive strength, lower thermal conductivity, and smaller environmental impact in comparison to cement-based foamed materials with comparable dry density.

Interaction between material and process parameters during 3D concrete extrusion process

Extrusion of cement-based materials in additive manufacturing is influenced by a complex interaction of various material and process parameters. This study aims to investigate the impact of rheological properties and printing parameters on the extrudability of cement-based materials as well as the interaction between rheological properties of print materials and extrusion speed, as a key printing process parameter. 20 different print materials with diverse rheological properties were extruded at 10 different extrusion speeds. The effect of material parameters (i.e. rheological properties) and process parameters (i.e., extrusion speed) and their interaction during the extrusion process were evaluated using filament continuity, conformity and consistency. At a constant printing speed, a higher yield stress adversely impacted filament continuity in mixtures with a yield stress of over 260 Pa, whereas viscosity showed minimal influence on filament quality within the tested range of the rheological properties. The results of this study highlighted a significant correlation between material and process parameters and that adapting process parameters to variations in material properties is crucial for meeting printing criteria. The filament consistency of the mixtures with high yield stress was more sensitive to change in the extrusion speed than that of mixtures with low yield stress. An opposite trend, however, was observed for filament conformity where low yield stress mixtures showed a higher sensitivity to the extrusion speed. A procedure was suggested and applied to determine the optimum extrusion speed. Optimal extrusion speeds enabled printing mixtures with a broader spectrum of rheological properties with an acceptable visual quality, filament conformity and consistency requirements. With extrusion speed adjustment, the extrudability window was expanded from dynamic yield stress of 108–126 Pa to 108–263 Pa and plastic viscosity of 8.2–12.3 Pa.s to 5.1–16.4 Pa.s.

Effect of steam curing regime on the mechanical properties, drying shrinkage, and microstructure of mortar in high-altitude areas with low air pressure

Low air pressure in plateau regions impacts the microstructure and macroscopic properties of cement-based materials by altering water transport. However, the efficiency of steam curing, a frequently-used curing approach, under these conditions has been inadequately studied. This work compares the effects of steam curing on the mechanical properties, drying shrinkage, and microstructure of cement-based materials at low air pressure. Results show that low air pressure decreases the compressive strength and increases the drying shrinkage of steam-cured mortar due to reduced hydration and increased total pore volume. Optimally, a steam curing temperature of 40°C to 60°C minimizes thermal damage, and a pre-curing time of 3 hours yields the best mechanical properties and drying shrinkage. Additionally, a field case confirms the effectiveness of the proposed steam curing regime; the demolding strength of precast beams meets engineering standards, and drying shrinkage fluctuates significantly with daily temperature changes. Notably, a 25.30 % difference in 90-day drying shrinkage between steam-cured and non-steam-cured specimens underscores the necessity of steam curing in high-altitude areas. These findings are crucial for optimizing steam curing practices in low-pressure environments.

Utilization of Granulated Blast Furnace Slag in Cement Mortar: Performance Analysis Against M-Sand

This study aims to explore the feasibility of incorporating Granulated Blast Furnace Slag (GBFS) as a sustainable alternative to manufactured sand (M-Sand) in cement mortar, to enhance both environmental sustainability and mechanical performance. The research involves a systematic investigation where M-Sand is progressively replaced by GBFS at varying levels of 10%, 20%, 30%, 40%, and 50%. The effects of these replacements are evaluated through a series of tests that focus on the mortar's physical properties, as well as its compressive and tensile strengths. Experimental results reveal that replacing 30% of M-Sand with GBFS produces the most favorable outcomes, with the compressive strength of the mortar exceeding that of the control mix by 12% after 28 days. The tensile strength also showed marked improvements at this replacement level. However, when the replacement level exceeds 30%, both compressive and tensile strengths begin to diminish, indicating that excessive substitution may adversely affect the mortar's structural integrity. The findings of this study provide valuable insights into the optimal use of GBFS in cement mortar, demonstrating that a 30% substitution not only enhances strength characteristics but also contributes to more sustainable construction practices by reducing reliance on natural sand resources. This research supports the potential of GBFS as a viable material for improving the environmental profile and durability of cement-based materials.

A Review of the Utilization of Recycled Powder from Concrete Waste as a Cement Partial Replacement in Cement-Based Materials: Fundamental Properties and Activation Methods

Recycled powder (RP) is the primary by-product generated during the reclamation process of construction and demolition waste (CDW). There is existing literature on the use of RP as supplemental cementitious materials (SCMs) in cement-based materials, but a comprehensive evaluation on the characteristics of RP generated from concrete waste has been missing until now. This paper critically reviews the use of RP from concrete waste in cement-based materials, as concrete waste makes up a significant amount of CDW and other components have designated recycling methods. In this sense, this study conducted a critical analysis on the use of RP as an SCM, using detailed literature research. The technology used for producing RP is detailed along with its chemical, mineralogy, and microstructural characteristics. Fresh-state properties in cementitious matrices with RP are introduced with the view of mechanical grinding, thermal activation, carbonation, chemical treatment, biomineralization, mineral addition, nano activation, and carbonation. The review highlights the significant potential of utilizing RP in cement-based materials. Specifically, RP can be advantageously utilized in the production of value-added construction materials.

A novel ultrasonic-velocity-based concrete carbonation monitoring method based on step-wise stretching technique

Carbonation is a common and slow process that occurs in cement-based material, resulting in durability degradation of reinforced concrete structures. In this research, the relative velocity change (d v/ v) of both ultrasonic direct waves and coda waves are extracted based on the step-wise stretching method for concrete carbonation monitoring. To this end, two-dimensional mesoscale models are established to investigate the ultrasonic propagation behaviors and assess the effectiveness of direct waves and coda waves on concrete carbonation monitoring. The numerical results indicate that direct waves could evaluate the initial carbonation, but exhibit limited sensitivity for severe carbonation. Conversely, the d v/ v values of coda waves show a linear correlation with carbonation depth in all conditions. Accelerated concrete carbonation experiments are conducted to validate the numerical findings. The experimental results and numerical findings mutually corroborate, validating the effectiveness of velocity changes of coda waves on all-stage concrete carbonation monitoring. This research contributes a novel method for monitoring concrete carbonation and enhances the understanding of ultrasonic wave propagation in concrete.

Microstructural Analysis of the Effect of Using Nano-silica on the Mechanical Properties of Cement–Sand Mortar Under the Effect of Heat

The performance of cement-based materials depends on the characteristics of solid particles at the nano-scale or nanometer porosities in the interfacial transition zone between cement particles and aggregate. Heat significantly affects the properties of these particles and the connection between them. Accordingly, the present study seeks to investigate the effect of nano-silica on the strength parameters of sand–cement mortar at high temperatures. In this regard, the sand–cement mortar was prepared by replacing 5, 10, and 15 percent of cement with nano-silica. The specimens were subjected to temperatures of 25, 100, 200, 400, 600, and 800 °C after curing at the ages of 3, 28, and 90 days. The effect of high temperatures on the physical and mechanical properties of sand–cement mortar was analyzed using macro-structural tests of compressive strength, loss in weight, and water absorption, and microstructural tests of X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results revealed that the macro-structural behavior of sand–cement mortar highly depends on the microstructure and changes in cement nanostructures during heat treatment. Primary portlandite and C–S–H nanostructure were destroyed at 600 °C, and alite, belite, and β-wollastonite were formed at 800 °C. Adding nano-silica improved the strength properties of sand–cement mortar against heat, so the compressive strength of 28-day specimens containing 15% nano-silica increased from 13.9 to 19.2 MPa at a temperature of 800 °C.

Durability of a Metakaolin-Incorporated Cement-Based Grouting Material in High Geothermal Tunnels

Durability of a Metakaolin-Incorporated Cement-Based Grouting Material in High Geothermal Tunnels

Unraveling the reaction mechanism of alkali-activated materials through multi-scale modeling

As an environmentally friendly alternative to cement-based materials, alkali-activated materials (AAM) have attracted much attention due to their significant ability to reduce greenhouse gas emissions and effectively utilize industrial waste. Three Si-Al monomers ([SiO2(OH)2]2-, [SiO(OH)3]-, and [Al(OH)4]-) serve as the fundamental building blocks for the formation of AAM gels. Simulating their polycondensation reactions (PR) among these monomers is of paramount importance but faces a delicate balance between precision and efficiency. To unravel the PR mechanisms, we have integrated reactive force field molecular dynamics (MD) simulations with first-principles calculations based on density functional theory. Our 100ps MD simulations reveal that Al monomers exhibit faster reaction rates and lead to the formation of Si-Al oligomers with diverse structures. Subsequent first-principles calculations on transition state models derived from MD results uncover that PR pathways involving Al monomers possess lower energy barriers, which are correlated with changes in chemical bond strength arising from electronic orbital transitions. Our study, for the first time, establishes an intrinsic link among five hierarchical levels: electronic orbital structure, chemical bond strength, reaction energy barrier, reaction rate, and reaction scale. This provides invaluable theoretical guidance for designing energy-efficient and low-barrier reaction pathways for AAM gel formation.

Investigating the factors affecting sustainability of ready mix concrete plants: case study of Pune region

Construction industry plays a significant role in the economic development of the nation. Due to site and other constraints, concreting is preferred by ready mix concrete (RMC) plants. It is very well-known fact that the construction industry immensely contributed for CO2 emission mainly from cement-based materials. One of the way to achieve smart city objective to effectively manage ready mix concrete plants. While opting for RMC over site mixing offers various advantages. In this study, key factors governing the sustainability and energy consumption of RMC plants are identified. This study investigates the efficiency and sustainability of RMC production in Maharashtra, suggesting that its efficiency hinges on various factors. Through a constructivist perspective, the research examines twelve RMC plants in Pune mainly and other parts of Maharashtra, finding that power supply, plant output, and capacity require sustainability. While raw material supply is deemed sustainable, management methods and product control were found lacking. The study identifies challenges affecting demand, such as regulatory issues, management issues and technological limitations. The conclusion emphasizes the need for alternative and sustainable power sources, skilled labor, and improved business processes to enhance RMC production efficiency in Maharashtra, recommending measures like waste reuse and innovative advancements. This study will help the stakeholders in prioritizing the resources and process towards more sustainable way.