Silica Fume Research Articles

Computer-Aided Design of 3D-Printed Clay-Based Composite Mortars Reinforced with Bioinspired Lattice Structures.

Towards a sustainable future in construction, worldwide efforts aim to reduce cement use as a binder core material in concrete, addressing production costs, environmental concerns, and circular economy criteria. In the last decade, numerous studies have explored cement substitutes (e.g., fly ash, silica fume, clay-based materials, etc.) and methods to mimic the mechanical performance of cement by integrating polymeric meshes into their matrix. In this study, a systemic approach incorporating computer aid and biomimetics is utilized for the development of 3D-printed clay-based composite mortar reinforced with advanced polymeric bioinspired lattice structures, such as honeycombs and Voronoi patterns. These natural lattices were designed and integrated into the 3D-printed clay-based prisms. Then, these configurations were numerically examined as bioinspired lattice applications under three-point bending and realistic loading conditions, and proper Finite Element Models (FEMs) were developed. The extracted mechanical responses were observed, and a conceptual redesign of the bioinspired lattice structures was conducted to mitigate high-stress concentration regions and optimize the structures' overall mechanical performance. The optimized bioinspired lattice structures were also examined under the same conditions to verify their mechanical superiority. The results showed that the clay-based prism with honeycomb reinforcement revealed superior mechanical performance compared to the other and is a suitable candidate for further research. The outcomes of this study intend to further research into non-cementitious materials suitable for industrial and civil applications.

REVIEW: AN EXPERIMENTAL STUDY ON EFFECT OF NANO MATERIALS ON STRENGTH OF CONCRETE AND PLANE STRESS ANALYSIS USING ANSYS SOFTWARE

These days, making efficient and cost-effective use of resources has taken precedence. The main ingredient in concrete, cement has been under criticism in recent years for the quantity of CO2 released during production. Although cement has better mechanical properties, it hasn't been able to live up to the expectations in terms of durability. Owing to cement's shortcomings, scientists started looking into additives that would enhance concrete's qualities while also making it stronger and lighter. Fly ash, silica fume, and other micro particles were added to cementitious materials to improve their compactness, strength, and durability. These additives were also selected because they are eco-friendly by products of industrial waste that may be handled ethically. Fly ash has significant disadvantages because it is not good for initial strength increase and setting time. Because silica fume affects cementitious material performance, researchers have recently become interested in combining it with ceramic waste and rice husk ash. A more effective way to utilize rice husk ash, a by-product of rice cultivation, would be to replace 10% to 15% of cement. Studies have shown improvements in the durability performance of recycled ceramic waste concrete and rice husk ash concrete. There are issues since the RHA production process is quite time-consuming. With the discovery of nano-particles (NP) smaller than 100 nm, researchers have advanced the field of nanotechnology to new levels. The mechanical properties of many materials, including polymers and cementitious materials, can be enhanced by NP. NP is also helpful in the fields of food, engineering, and medicine. This led researchers to investigate the effects of nano-silica (NS) on concrete in further detail. Nano materials can improve the compressive strength and ductility of concrete. In this project an effort will be made to increase the compressive strength of concrete using Nano materials and waste product like GGBS. Also plane stress analysis of concrete cubes and cylinders is to be done using Ansys Software to find deformation, principal stresses and shear stresses. Keywords: Nano –Silica, Nano Titanium dioxide, Ansys, GGBS, Compressive strength

A Cementless Binder Based on High-Calcium Fly Ash, Silica Fume, and the Complex Additive Ca(NO3)2 + MgCl2: Phase Composition, Hydration, and Strength

A Cementless Binder Based on High-Calcium Fly Ash, Silica Fume, and the Complex Additive Ca(NO3)2 + MgCl2: Phase Composition, Hydration, and Strength

Effect of nano-silica on the flexural behavior and mechanical properties of self-compacted high-performance concrete (SCHPC) produced by cement CEM II/A-P (experimental and numerical study)

The extensive use of cement exacerbates the greenhouse effect by increasing carbon dioxide (CO2) emissions. So, many standards recommend using Portland-composite cement in construction as one of the methods for reducing CO2 emissions, especially cement CEM II/A-P. This paper presents an extensive experimental and numerical study to investigate the effect of micro and nano-silica on the flexural behavior and mechanical properties of Self-Compacted High-Performance Concrete (SCHPC) produced by cement CEM II/A-P. The extensive experimental work consisted of eight mixtures: three with micro-silica (MS), four with nano-silica (NS), and a reference mixture without silica. For both MS and NS, different percentages of adding or replacement content were tested to study their effect on the following: (a) the workability of fresh concrete, (b) concrete compressive strength, (c) splitting tensile strength, (d) flexural behavior including flexural tensile strength, and (e) the optimum percentage of each of the MS and NS to get the maximum structural and economic benefits of using for SCHPC with CEM II/A-P. Also, through a statistical program, these experimental results were used to obtain accurate formulae that could predict both the splitting tensile strength (fsp) and modulus of rupture (fctr) for SCHPC with adding nano-silica. In addition, the numerical study verified the experimental results based on the finite element program ANSYS. The flexure behavior of SCHPC beams is verified using the Microplane model (recently added to ANSYS). The experimental results showed that adding NS is more effective than replacing or adding MS for SCHPC mixture with CEM II/A-P to increase the concrete compressive strength, splitting tensile strength, and flexural tensile strength, especially for the mixture with adding NS content of 4 %. The numerical results showed the ability of the coupled damage-plasticity microplane model to simulate the flexural behavior of the tested SCHPC beams with MS or NS well. This research confirms nano-silica's structural and economical efficiency in the behavior of SCHPC beams. It was found that the optimum percentage of adding NS is 4 % for SCHPC mixtures with CEM II/A-P.

Development of hybrid gradient boosting models for predicting the compressive strength of high-volume fly ash self-compacting concrete with silica fume

In an effort to extend the service life of structures under harsh exposure conditions and reduce the carbon dioxide emissions from cement production, researchers are examining the performance of cement concretes with different mineral admixtures. This study focuses on self-compacting concrete (SCC) incorporating high-volume fly ash (HVFA) and silica fume (SF) as supplementary cementitious materials (SCMs). The aim is to investigate the fresh and hardened properties, particularly the compressive strength, of these combinations. SCMs were used to replace varying amounts of cement, with SF showing the greatest improvement in mechanical characteristics across all age groups. Advanced modelling techniques, including Gradient Boosting (GB), Gradient Boosting-Particle Swarm Optimization, Gradient Boosting-Bayesian Optimization, and Gradient Boosting-Differential Evolution (GB-DE), were employed to analyse the strength characteristics of HVFA-SCC. The GB-DE model emerged as the most accurate, with an R² value of 0.995029 and an RMSE of 0.023862. Additionally, an open-source GUI based on GB-DE is introduced to provide engineers with a transparent tool for optimizing concrete mix designs, addressing the opacity of traditional machine learning models.

ANN‐based analysis of the effect of SCM on recycled aggregate concrete

AbstractRising environmental awareness has prompted in‐depth studies on how the concrete industry affects the environment. Using recycled concrete aggregates (RCAs) and supplementary cementitious materials (SCMs) in concrete manufacturing provides advantages for sustainability. However, the broader chemical composition of SCMs and the inferior qualities of RCAs compared with natural aggregates (NAs) often lead to a decrease in concrete mechanical strength. The difficulty lies in foreseeing how the inclusion of SCMs and RCAs will affect the concrete compressive strength. The artificial neural network (ANN) approach presented herein can precisely forecast the recycled aggregate concrete (RAC) compressive strength, even when incorporates SCMs. The analysis employing the connection weight approach (CWA) determines how input variables influence compressive strength. Results indicate silica fume contributes most to compressive strength, followed by cement content, silica modulus, fine natural aggregate dosage, and coarse natural aggregate. Additionally, the amount of water utilized, the water/cement ratio, and the presence of RCA are all detrimental to compressive strength. The adverse effect of the cementitious materials' alumina modulus can be attributed to increased water demand during their reaction. Performance metrics of the final ANN model on the testing data subset include R2 = 0.94, and RMSE = 3.11, utilizing 834 data observations after outlier treatment for training and validation purposes. In summary, the ANN‐based approach demonstrates its efficacy in predicting concrete compressive strength when incorporating SCMs and RCAs, shedding light on the influential factors in concrete performance.

Sustainable preventive maintenance of MMC-based concrete building structures in a harsh environment

The construction industry plays a significant role in environmental strain, attributed mainly to its substantial resource consumption, primarily driven by the surge in residential construction. Modern Methods of Construction (MMC) presents an innovative paradigm for designing and constructing infrastructure and buildings more efficiently, using conventional materials with unconventional techniques. The article aims to apply this approach to an MMC-based building structure, minimizing its life cycle impact by optimizing the consumption of building materials, with particular attention to the effects of the maintenance phase from a preventive point of view. This study focuses on assessing the sustainability of reinforced concrete flat slabs employing a hollow structural body system, explicitly emphasizing environmental aggressiveness factors contributing to corrosion, such as carbonation and chlorides. The research explores ten design options for a waterfront public residential building, examining their impact on the economy, the environment, and even society regarding the maintenance cycles required over the structure's lifetime, depending on the preventive strategy employed for each design. In assessing the sustainability of these options, researchers employed a combination of the best-worst method (BWM) and the VIKOR technique, considering nine criteria related to sustainability. The study found that 5 % silica fume concrete is the most cost-effective and environmentally friendly option, with hydrophobic impregnation reducing social impacts. However, compared to one- and two-dimensional evaluations, the study demonstrates the importance of simultaneously considering a design's life cycle's economic, environmental, and social impacts to achieve sustainability in maintenance with a holistic view. This approach led to an 86 % higher sustainability rating for a design using sulforesistant cement in the concrete mix than the baseline.

Synergistic effect of nano-to-macro waste glass of various particle sizes on ultra-high-performance concrete: Tradeoff between mix design parameters and performance through a statistical design approach

Ultra-high-performance glass concrete (UHPGC) is engineered for strength, ductility, and durability, aiming to address environmental and economic concerns associated with traditional ultra-high-performance concrete (UHPC). In this approach, we individually substituted traditional UHPC components—cement (C), silica fume (SF), quartz sand (QS), and quartz powder (QP) with ground waste glass materials (GWG). Recognizing that the performance of UHPC is influenced by the chemical interactions and packing density of its constituents, which primarily depend on particle-size distribution, our current study focuses on the synergistic effects of these factors. We explored how nano to macro size GWG can simultaneously replace all traditional UHPC components and affect its properties. Employing the Design of Experiment allowed the establishment of statistical equations. Contour diagrams predicted the individual and synergetic effect of mix design parameters on UHPGC's fresh and mechanical properties, with a high correlation (R2 ≥ 0.98) and low error (≤8 %). Validation with 18 additional mixtures confirmed the models' precision. Our research established the production of a superior UHPGC with 40%–100 % lower traditional components (C, SF, QP, and QS) and 65 % less superplasticizer demand. The embodied energy, CO2 emissions, and production cost reduced by 65 %, 38 %, 36 %, and 32 %, respectively. This approach can enhance UHPGC's integrity and environmental sustainability.

Strain-hardening magnesium-silicate-hydrate composites (SHMSHC) utilizing reactive magnesia cement (MgO) and calcined clay (metakaolin)

This study demonstrated the feasibility of utilizing calcined clay (metakaolin) as a silica source for the development of polyethylene (PE) fiber-reinforced strain-hardening magnesium-silicate-hydrate composite (SHMSHC). The study also discussed the effects of variation in the Mg/Si ratio of the mixture when pure silica source (silica fume with SiO2 content >90 %) is replaced with metakaolin (SiO2 content ⁓ 51 %) on the mechanical performance of SHMSHC. A comprehensive mechanical characterization of SHMSHC at composite scale and fiber-matrix interaction effects was conducted. The damage characterization was carried out using residual crack width and spacing analysis. The chemical characterization of the MSH matrix (SHMSHC without fibers) was performed using XRD, TGA, and FTIR, and the microstructural investigation was done using FE-SEM. The MgO-metakaolin paste based SHMSHC showed compressive strength of 51.9 MPa, tensile strength of 5.0 MPa, and tensile strain capacity of 4.7 %, demonstrating the feasibility of calcined clay utilization in SHMSHC. The tensile strain capacity was reduced after the addition of aggregates in SHMSHC. The study demonstrated that the variation in the Mg/Si ratio significantly affects the toughness of the MSH matrix and fiber-matrix interaction characteristics, influencing the strain-hardening potential of SHMSHC.

Utilizing silica fume and synthetically produced mesoporous silicas for simulated flue gas CO2 adsorption

ABSTRACT Carbon capture and storage (CCS) is crucial in mitigating greenhouse gas emissions. Solid adsorbents, notable for their reusability and corrosion resistance, are gaining attention in CO2 gas separation. This study uses Silica fume as an adsorbent and silica source for SiO2 and MCM-41 silica-based adsorbents. Silica was extracted via an alkaline dissolution method, and adsorbents were synthesized using a CO2-induced precipitation method, chosen for its shorter synthesis time and CO2 utilization. The effects of pore volume, average pore diameter, and specific surface area on amine loading and CO2 adsorption capacity were investigated using CTAB surfactant in SiO2 synthesis, resulting in MCM-41. The synthesized adsorbents were modified with TEPA and DEA amines due to their high affinity for CO2. After determining optimal amine loading, the impact of combining TEPA with DEA was examined. The highest CO2 adsorption capacity under simulated flue gas conditions (15% volume CO2 and 85% volume N2) was 198 milligrams per gram of adsorbent for the SiO2 adsorbent functionalized with 50% by weight amine (28% TEPA and 22% DEA). Variations in CO2 adsorption over time, the influence of adsorbent quantity on adsorption capacity, the affinity of the adsorbent for N2 adsorption, and the adsorption–desorption cycle were investigated. The 28%TEPA-22%DEA-SiO2 adsorbent emerged as the optimal choice due to its large total volume and average pore diameter, absence of a template in its structure, excellent performance in CO2 adsorption, lack of affinity for N2, and robust adsorption–desorption stability.

Effect of dispersion behavior of silica fume on the rheological properties and early hydration characteristics of ultra-high strength mortar

Silica fume plays a crucial role in ultra-high performance cementitious materials, but its dispersion, influenced by varying densification levels, leads to different degrees of agglomeration. However, the precise impact of this on rheological properties and early hydration characteristics of ultra-high performance cementitious materials remains unclear. This study assesses the impact of highly densified silica fume (HDSF), moderately densified silica fume (MDSF), and raw silica fume (RSF) on the rheological prperties of ultra-high strength mortar (UHSM). Additionally, the early hydration characteristics of UHSM influenced by these silica fumes are investigated through both heat of hydration and penetration resistance methods. The results showed that HDSF contained numerous large agglomerates, contrasting with MDSF and RSF, where the agglomerate sizes were comparable to those of cement particles. As the content of HDSF increased, the yield stress, viscosity, and thixotropy of UHSM gradually rose, accompanied by a notable decrease in hydration rate. Conversely, increasing MDSF and RSF content initially decreased and then increased these rheological properties, while the hydration rate remained relatively unchanged. The distribution behavior of the silica fumes influences the rheological properties of UHSM through water film thickness (particle spacing). Large agglomerates in HDSF reduce the activity of the entire cementitious system, significantly decreasing the hydration rate. In contrast, MDSF and RSF primarily influence the particle spacing within the cementitious system, subsequently impacting the hydration rate. This study provides theoretical insights and practical guidance for construction professionals in selecting appropriate silica fume for designing and regulating ultra-high performance cementitious materials performance.

Comparison of SEM and TPM methods for evaluating the effect of nano-silica and silica fume on the fracture behavior of SCLC

ABSTRACT This study compares the fracture parameters of self-compacting lightweight concrete (SCLC) obtained from two-parameter model (TPM) and size effect method (SEM). Moreover, the influence of using silica fume and nano-silica on the fracture parameters and mechanical properties of SCLC was evaluated. For this purpose, eight mix designs were made by replacing 0, 1, 3, and 5% of the cement weight with nano-silica and using 0 and 10% of the cement weight with silica fume. The SCLC incorporating 3% nano-silica and 10% silica fume was the best mix design. This mix enhanced the compressive strength, tensile strength, and elasticity modulus of SCLC by about 36, 17, and 18%, respectively. Based on SEM, this mix increased the fracture energy and fracture toughness by about 32% and 25%, respectively. According to TPM, this mix improved the mentioned parameters by approximately 33 and 25%, respectively. The average value of differences in the fracture energy and fracture toughness attained from SEM and TPM were about 2% and 1%, respectively. The average difference in the critical crack tip opening displacement (CTODc) results was about 6%.

Development of a prediction tool for the compressive strength of ternary blended ultra-high performance concrete using machine learning techniques

ABSTRACT This study addresses the challenge of quantifying the complex and non-linear correlations between the technical properties of ultra-high-Performance concrete (UHPC) and its mixture composition through conventional statistical methods. To tackle this, this study employs five advanced machine learning methods: Random Forest (RF), Long-Short-Term Memory, Convolutional Neural Network, K-Nearest Neighbor, and Adaboost. A dataset comprising 308 UHPC compressive strength tests with varying amounts of cement, silica fumes, superplasticizers, ground granulated blast furnace slag, fine aggregates, coarse aggregates, age, and temperature was used to train these models. The models’ performance was validated using statistical metrics, regression error characteristic curve, SHAP analysis, and uncertainty analysis. Among the models, the RF model achieved the highest prediction accuracy with an R2 of 0.9877 and an RMSE of 0.0323. This study also introduces an open-source graphical user interface based on the RF model, providing engineers with a practical tool for estimating the compressive strength of UHPC and facilitating mix proportioning decisions. This interface aims to bridge the gap between machine learning predictions and practical applications in UHPC mix design.

Transport Characteristics and Corrosion Behavior of Ultra-High Performance Fiber-Reinforced Concrete with the Key Mix Parameters

The presence of low-quality coarse aggregates and exposure to aggressive conditions are the two major problems with the durability of concrete. Therefore, an alternative concrete with enhanced properties to prevent fluid and ionic mobility compared to conventional concrete is needed. This study investigated the effects of main mix parameters on the transport characteristics and corrosion behavior of ultra-high performance fiber-reinforced concrete (UHPFRC). A set of 27 UHPFRC mixtures with different combinations of w/b ratio, cement, and silica fume contents, based on a 33-factorial experiment design, were prepared and tested for water permeability, chloride penetrability, electrical resistivity, chloride profile, and corrosion current density. The results showed that UHPFRC mixtures exhibited excellent durability properties characterized by negligible water penetration (< 15 mm), negligible and very low chloride permeability when the w/b ratio was 0.15 (< 100 Coulombs) and up to 0.2 (< 300 Coulombs), respectively, and very low chloride concentrations at the rebar level (0.03–0.18 wt.%). All resistivity values were within the range of 26.7–78.8 kΩ cm (> 20 kΩ cm) and pH values were 12.41–13.01, indicating the implausible likelihood of corrosion in the UHPFRC mixtures. This was confirmed through the corrosion current density measurements of reinforced UHPFRC specimens after 450 days of chloride exposure, which were below the critical limit for the corrosion initiation of reinforcing steel. Finally, the experimental data were statistically analyzed and fitted for all the listed tests, and models were developed for them using the regression analysis such that regression coefficients were within 0.90–0.99.

Strength Characteristics of Bentonite Nano Clay Stabilized with Addition of Lime, Fly Ash, and Silica Fume for Soil Environmental Sustainability

The suboptimal engineering characteristics, including low tensile strength and significant compressibility volumetric changes, are the significant challenges faced during the construction of sub-structures in expansive Soil. The instability of the sub-structure leads to the settlement of the structure and compromises its safety and endurance. This paper explores how Bentonite nano clay (BNC) reacts with varying proportions of lime, Fly Ash, and silica fume. The ratios used for these additives were 2%, 4%, and 6%. The Compaction Characteristics and the stress-strain curve are analyzed. Incorporating silica fume into BNC leads to a decrease in both the liquid limit and the plasticity index. Concurrently, this addition increases the plastic limit of the clay. As the percentage of silica fume in the mixture rises, there is a corresponding decrease in the maximum dry unit weight and an increase in the optimum moisture content. Additionally, the introduction of silica fume contributes to an increase in the free swell but also it has an increase in the swelling pressure of clay. These results suggest that silica fume stabilization is an effective method for treating expansive clay.

Study on the electromagnetic transmission properties and mechanical properties of calcium aluminate cement paste by silica fume

Study on the electromagnetic transmission properties and mechanical properties of calcium aluminate cement paste by silica fume

Strength and Durability Performance of Recycled Aggregate Structural Concrete with Silica Fume, Furnace Slag, and M-Fine

Strength and Durability Performance of Recycled Aggregate Structural Concrete with Silica Fume, Furnace Slag, and M-Fine

Strength, Microstructure, and Life Cycle Assessment of Silicomanganese Fume, Silica Fume, and Portland Cement Composites Designed Using Taguchi Method

Strength, Microstructure, and Life Cycle Assessment of Silicomanganese Fume, Silica Fume, and Portland Cement Composites Designed Using Taguchi Method

A Review on the Recycling Waste Materials for Green Concrete

This has increased the generation of solid waste, creating environmental and economic problems on an international scale. The construction industry, one of the major environmental degrading and resource-consuming industries, plays a major role. This study examines how waste material is used in green concrete as a sustainable solution to minimize environmental burdens and save natural resources. Utilizing waste material such as silica fume, fly ash, recycled aggregates, and ground-granulated slag from blast furnaces (GGBFS), recycled plastic, and biopolymers, green concrete minimizes carbon emissions as well as reduces the need for virgin materials. In this paper, it is discussed how the application of such waste products in green concrete minimizes the carbon footprint and saves natural resources, whereas on the other hand, it also saves material and construction costs. Life cycle assessment studies and sustainability analysis give a valuable comparison in overall sustainability between green concrete and conventional concrete. Challenges and future directions in this field elucidate the uniformity of waste material quality, regulatory support, and public acceptance. The scope of further research lies in the development of material characterization, long-term durability studies, and technological advancement, which promise to deliver desired performance and applications of green concrete.

Effects of silica fume/ultrafine fly ash on the rheology and hardening of alkali-activated slag-waste ceramic powder paste

Fast setting and high viscosity are the two main obstacles to obtain desired rheological properties of alkali-activated materials (AAMs). This work aims to remove these obstacles by using a simple yet effective approach via introducing ultra fines with different characteristics. Here in the systems of alkali-activated slag-waste ceramic powder, the mechanism behind the effect of various ultra fines on rheological and hardened properties is studied. Results show that the introduction of ultrafine fly ash (UFFA) is beneficial to maintain good rheological properties and control setting, yet adding silica fume (SF) harms fresh performance due to the extremely low liquid film thickness. By 1H NMR and interstitial solution analysis, the large water demand for wetting SF rather than its dissolution, has been demonstrated to cause the insufficient dissolution of slag, which leads to lower Al3+ and Ca2+ concentrations and less precipitation of early gels. However, once gels start to precipitate, shorter particle spacing favors the rapid formation of percolation network in SF-systems, thus resulting in higher yield stress, viscosity and setting rate, as well as a faster decrease in mobile water. Furthermore, the incorporation of 5 %-10 % UFFA provides superior fresh performance and hardened properties. The results and relevant mechanisms of this study are essential towards better development of high-performance AAMs.