Effect Of Supplementary Cementitious Materials Research Articles

Effect of supplementary cementitious materials on the degradation of cement-based barriers in radioactive waste repository: A case study in Korea

This study focuses on investigating the chemical degradation characteristics of cementitious barriers used in low- and intermediate-level radioactive waste repository by reactive transport modeling. The impact of the blending with supplementary cementitious materials (SCMs) in the barriers on the chemical degradation was evaluated to find the optimum barrier design. A number of different barrier designs were examined by replacing ordinary Portland cement (OPC) by SCMs (i.e., fly ash, silica fume, and blast-furnace slag). The simulation results showed that silica fume blended barrier has better durability against chemical degradation by rainwater compared to fly ash or blast-furnace slag blended barriers. In addition, the chemical durability of silica fume-based barrier increased with increasing replacement level up to about 20 %. It seems that the amount of formed calcium silicate hydrate (CSH) in the initial cement-based barrier highly affects the overall chemical durability. The newly developed reactive transport model demonstrated its capability for understanding the barrier performance and investigating the optimal design of the barrier system.

Effect of collated fly ash, GGBS and silica fume on index and engineering properties of expansive clays as a sustainable landfill liner

The effect of supplementary cementitious materials (SCMs) such as fly ash (FA), GGBS and silica fume (SF) on the geotechnical index and engineering properties of expansive clays (EC) are studied in this research work. This manuscript aims to determine the workability (consistency limits (CL)), swellability (free swell index (FSI)), compaction properties, strength characteristics (UCS) and hydraulic conductivity (HC) of varied eighteen mix proportions of FA-EC (P-series), FA-GGBS-EC (Q-series) and FA-GGBS-SF-EC (R-series) are experimentally studied as a bottom liner in landfills. From the test results, CL and FSI significantly decreased in P, Q and R series, this is due to the effect of flocculation, a process that increases the average particle size of mix blends and also depletion of the double-diffusive layer thickness of EC by promoting the Ca2+ ions in the pore water from SCMs. The compaction parameters such as optimum moisture content decreased in all the series, due to the higher flocculation of mixes. However, maximum dry unit weight increased in Q and R and decreased in the P series. The UCS values increased with an increase in optimum SCMs quantities and with curing intervals tested at 0, 7, 14 and 28 days. The higher UCS value is attained at 40 %FA with EC (i.e. P2), 60 %FA-GGBS with EC (i.e. Q3) and 60 %FA-GGBS-SF with EC (i.e. R3) in R-series which confirmed to be optimum due to the loss of cementation action/reduced cohesion in the matrix. In the case of HC, P2, Q3 and R3 mixes are confirmed to be optimum and fall under the criterion standards of landfill liner as per USEPA recommendation. Overall, this work proves to be a novelty and shows the feasibility of various collated SCMs blended with EC as landfill liner material, furthermore, these mixes are optimized to combine with EC to create a sustainable landfill liner that fits with the United Nations sustainable goals of 2030

Synergistic effects of supplementary cementitious materials and compressive strength prediction of concrete using machine learning algorithms with SHAP and PDP analyses

In order to reduce the CO2 associated with cement production, this study explored the potential of rice husk ash (RHA) and fly ash (FA) as supplementary cementitios materials for partially replacing cement in concrete production. The study aimed to analyze the synergistic effects of a cement-based mixture consisting of RHA and FA in different proportions on concrete's fresh, hardened, non-destructive and microscopic properties. In addition to the experimental work, this study successfully applied machine learning to predict the compressive strength of RHA-FA concrete using three types of algorithms: ANN (Analytical Neural Network), XGB (Extreme Gradient Boosting), and GBM (Gradient Boosting Model). A total of 138 data points were used for this prediction, and statistical and parametric analyses were performed to define the impact of input parameters on the outcome. Furthermore, both destructive and non-destructive tests were conducted on hardened concrete, including compressive strength, split tensile strength, ultrasonic pulse velocity (UPV), and rebound hammer. The scanning electron microscope (SEM) was operated to analyze the microstructural characteristics of concrete. The compressive and split-tensile strength test results showed that the mixture with a higher percentage of fly ash and a lower percentage of rice husk ash achieved maximum strength. The X-ray Fluorescence (XRF) analysis revealed that both ashes contained a significant amount of silica, which gave them excellent pozzolanic properties. After 28 days, both the UPV and the rebound hammer strength align with the destructive compressive strength results. The study also employed SHAP (SHapley Additive exPlanations) and PDP (Partial Dependence Plot) analyses to identify the optimal range for each parameter's contribution to strength improvement. The machine learning models exhibited a strong correlation with the test results, achieving an R2 value of 0.84 for the XGBoost model.

Synergistic integration of waste fibres and supplementary cementitious materials to enhance sustainability of ultra-high-performance concrete (UHPC)

Efforts to improve the environmental sustainability of the construction industry involve exploring waste materials, environmentally friendly production processes and high performance materials like ultra-high-performance concrete (UHPC). Despite UHPC’s benefits, its widespread use is hampered by its high cost and environmental concerns. To address this, limestone filler and metakaolin were used to replace 30% of the cement, while recycled tyre steel fibres (RTSF) and production waste carbon fibres (CF) replaced the conventional factory-made fibres. Eight mixes underwent various tests in fresh state and hardened state, revealing initial negative effects of supplementary cementitious materials (SCMs) on strength and capillary absorption, which improved considerably over time. Fibres addition, especially hybrid fibres, increased strength and toughness without significantly affecting modulus of elasticity. RTSF at 1 vol% and 1.5 vol% positively impacted compressive strength and toughness, while 1 vol% CF improved flexural strength and capillary water absorption. Optimal contents varied for the hybrid fibre mixes depending on the tested property, with overall best results in compressive strength, toughness and specific energy absorption. The hybrid mixes outperformed the RTSF mixes but lagged behind the CF mixes in terms of flexural strength and capillary water absorption. A multi-criteria analysis was conducted to determine the optimum mix design, taking into account factors such as performance, cost, and environmental impact. This analysis highlighted the potential of the supplementary materials and fibres to improve the environmental and economic efficiency of UHPC while maintaining or even improving the tested properties.

Relationship between Chloride Migration, Bulk Electrical Conductivity and Formation Factor of Blended Cement Pastes

Abstract This study investigates the links between the non-steady-state chloride migration coefficient, the bulk electrical conductivity and the formation factor of blended cement paste specimens. 18 different binders were tested: two Portland cements (low- and high-alkali) in combination with limestone filler, fly ash, calcined clay, two biomass ashes, sewage sludge ash and crushed brick, as well as two Portland composite cements. In addition, the latter and the low-alkali Portland cement were tested in concrete as well for comparison. Mixes with high-alkali cement showed better resistance to chloride transport, and the effect of supplementary cementitious materials was found to be strongly linked with their reactivity. Moreover, the results showed a clear correlation of the migration coefficient with the bulk electrical conductivity and, to a lesser extent, with the formation factor. However, these relationships are strongly influenced by the methods used to determine conductivities and they need to be validated for higher maturities. Finally, the results suggested a fairly good correspondence between the results obtained on paste and concrete.

Effects of Supplementary Cementitious Materials on the Hydration of Ultrahigh-Performance Concrete

Effects of Supplementary Cementitious Materials on the Hydration of Ultrahigh-Performance Concrete

Flowability and Strength Characteristics of Binary Cementitious Systems Containing Silica Fume, Fly Ash, Metakaolin, and Glass Cullet Powder.

The present study examines the effects of supplementary cementitious materials (SCMs) on the flowability and strength development of binary mixes. This study was primarily motivated by the need to bridge the knowledge gap regarding paste and mortar mixes containing binary cement from a variety of performance perspectives. This study examined the flowability and strength development of binary mixes in their pastes and mortars when they contain various doses of silica fume (SF), fly ash (FA), metakaolin (MK), and glass cullet powder (GP) compared with the control mix. While the presence of SF and MK reduced workability because of the nature of their particles, the addition of FA and GP improved it to a certain extent because of the spherical and glassy nature of their particles, respectively. In addition, GP was used to compare its performance against SF, MK, and FA as an alternative cementitious material. In this study, the GP performed comparably to the other SCMs investigated and was found to be satisfactory. An investigation of the rheological properties, heat of hydration, thermal analysis, and pore systems of these mixes was conducted. Compared to the control mix, the presence of 5% GP improved the rheological properties and reduced the heat of hydration by 10%. The reduced workability in SF and MK mixes resulted in a lower content of pore water, while GP and FA incorporation enhanced it, owing to improved workability. The pore area is related to the pore water, which is directly related to improved workability. According to the following order, SF > MK > GP > FA, the strength was highest for mixes containing SF and MK, whereas, with GP and FA, there was a gradual reduction in the strength proportional to replacement level and improved workability. SF, GP, and FA can be identified as performance enhancers when formulating ternary and quaternary cementitious systems for low-carbon cement.

Effect of Supplementary Cementitious Materials with Similar Specific Surface Area on Cementitious Composite Systems

Abstract This study investigated the effect of the mechanical and durability properties of cementitious composite systems with supplementary cementitious materials (SCMs), including fly ash (FA), ground granulated blast furnace slag (GGBS), and bottom ash (BA), with similar specific surface areas (∼3,300 cm2/g). FA, GGBS, and BA were ground to a specific surface area of ∼3,300 cm2/g (about the cement-specific surface area) and then replaced with cement at 5 %, 10 %, 15 %, and 20 % replacement ratios. The compressive strength, flexural strength, length change, and rapid chloride ion permeability of the cementitious composites incorporating FA, GGBS, and BA with similar specific surface areas were recorded after 7-, 28-, and 90-day curing periods. As a result, cementitious composites containing GGBS improved the mechanical and durability properties at the maximum rate. It was shown that the properties of cementitious composites containing 20 % GGBS yielded better results than the control specimens without any SCMs.

ANN approach to evaluate the effects of supplementary cementitious materials on the compressive strength of recycled aggregate concrete

The growing awareness of environmental issues has triggered significant research into the impacts generated on the environment during concrete production. To improve sustainability in this process, ordinary Portland cement (OPC) and natural aggregates (NA) have been replaced by recycled concrete aggregates (RCAs) and supplementary cementitious materials (SCMs) to reduce the negative issues to the environment. However, the use of SCMs can be challenging due to their complex chemical composition, and RCAs are often of inferior quality compared to NAs, leading to reduced concrete strength. To address these issues, an artificial neural networks (ANN) model has been used for calculating the compressive strength of concrete mixes that oodórate SCMs and RCAs. To train the model, 1181 concrete mixtures from 116 sources were included, considering parameters such as hydraulic reactivity, silica, and alumina modulus. In this research was found that the ANN model is an effective instrument to predict concrete strength even with the use of SCMs and RCAs. The analysis of input variables using the Connection Weight Approach (CWA) concludes that silica fume is the external material that, when mixed with RCA, significantly improves the resistance of concrete, followed by the reactivity modulus of cementitious materials, cement content, silica modulus, fine NA content, and coarse NA dosage. Conversely, excessive ood dosage, high ood/cement ratio, and excessive RCA content (fine and coarse) negatively affect concrete strength.

Utilization of Various Industrial Wastes in Ordinary Concrete Under Normal Manufacturing Conditions

The main objective of the present work is to evaluate using alkaline wastewater from pot factories (recycled NaOH solutions with variant concentrations and pH values) along with waste powders possessing pozzolanic properties, such as supplementary cementitious materials and stone waste dust in concrete under normal manufacturing conditions. An extensive analysis of the chemical components and the physical properties of the used materials was achieved. Both supplementary cementitious materials and stone waste dust materials were used as 0%, 10%, 20%, or 30% partial cement replacements using either tap water or alkaline wastewater to make samples for physical, mechanical, and microstructure testing. Thermodynamic modeling was used to evaluate the effect of the flushed alkaline industrial water and the powders on the hydration products. The results showed an increase in the workability of the mixes made with alkaline wastewater, an increase in water absorption for samples made with alkaline wastewater at the age of 28 days, and a relative decrease in compressive strength at 3 and 28 days, respectively. Despite the reduction in mechanical strength, most samples made with alkaline wastewater and 10%, 20% supplementary cementitious materials, or stone waste dust materials gave an accepted concrete grade. The microstructure analysis showed a slight change in pores distribution, pores values, and hydration products at 3 and 28 days. The thermodynamic analysis provided insight into data on the effect of supplementary cementitious materials, stone waste dust materials, and alkaline wastewater on hydration products. Finally, the combination of these wastes in concrete production showed satisfactory conclusions.

The Study of the Effects of Supplementary Cementitious Materials (SCMs) on Concrete Compressive Strength at High Temperatures Using Artificial Neural Network Model

In this study, an artificial neural network (ANN) model was developed to predict the compressive strength of concrete containing supplementary cementitious materials (SCMs) at high temperatures. For this purpose, 500 experimental results were collected from the available literature. The effective parameters in the model are the volumes of coarse and fine aggregates, water, cement, coarse-aggregate type, percentage SCMs as the cement replacement, temperature levels, and test methods. The proposed ANN model was developed at a correlation coefficient of 0.966. A parametric study was conducted to evaluate the impact of the combined effects of input parameters (aggregate types and SCM content) on the relative compressive strength of concrete at high temperatures. It was shown that siliceous aggregate has a better performance by producing stronger bonds with cement paste than calcareous aggregates. The optimum SCM contents depend on the aggregate types. The optimum silica fume (SF) content for concrete with a water-to-binder ratio of 0.6 subjected to high temperatures is 8% and 3% for siliceous and calcareous concrete, respectively. The analysis of the ANN model has provided a conclusive understanding of the concrete behaviour at high temperatures.

Study on the effect of supplementary cementitious materials on the volume stability of mortar mixed with laboratory-made high-content fluorine-type accelerator

The high-content fluorine-type accelerator (AF) can be prepared from fluorine-containing wastewater due to its low cost and is widely used in many projects. In this study, the fluorine-type alkali-free liquid accelerator was synthesized by simulating fluorine-containing waste liquid in the experiment, and its performance was tested and shown to meet the standard requirements. Subsequently, three supplementary cementitious materials (granulated blast furnace slag-GBFS, fly ash-FA, and silica fume-FS) were used to study the effect of supplementary cementitious materials on the setting time, mechanical properties and volume stability of mortar mixed with accelerators. The results show that the addition of supplementary cementitious materials shortens the setting time of the cement paste, while maintaining the requirements on compressive strength. Among these materials, the incorporation of silica fume makes the best effect of shortening the setting time, and yields the highest increase in compressive strength. In the 180-day test, both FA and GBFS can reduce the autogenous shrinkage and drying shrinkage of mortar, and the shrinkage reduction effect of FA is more prominent. FS significantly increases the autogenous and drying shrinkage of the mortar. By observing the changes to mass and humidity under the drying conditions of mortar, it is found that FS can effectively reduce mass loss and humidity change. This is because the early hydration reaction of FS occurs earlier than that of FA and GBFS, and it can play a role in refining the pore structure. However, the addition of FS aggravated the shrinkage of the mortar by increasing the pore size of 5–50 nm, resulting in higher capillary tensile stress and greater shrinkage driving force. FA increased the mass loss and internal humidity reduction of the mortar, but was less driven by capillary tensile stress due to coarsening of the pore structure. This study provides theoretical guidance for practical construction application.

Study on the Effect of Supplementary Cementitious Material on the Regeneration Performance of Waste Fresh Concrete

In the preparation of ready-mixed concrete, it is inevitable to produce waste fresh concrete (WFC). An efficient, low-cost and environmentally friendly recycling scheme is the key to WFC recycling. In this work, we directly added some unhardened WFC to fresh concrete to prepare recycled fresh concrete (RFC); on this basis, fly ash (FA) and nano-silica (NS) were added as supplementary cementitious material (SCM) to obtain modified recycled fresh concrete (RFC-SF). Then, the mechanical properties, slump, freeze–thaw resistance, phase structure of the hydration products and hydration process in RFC were studied. The results show that the addition of FA and NS significantly improved the comprehensive performance of RFC. Compared with RFC, the compressive strength of RFC-SF with 15% FA and 3% NS increased by 15.2% and 50.3% at 7 d and 90 d, respectively, and the splitting tensile strength increased by 20.5% and 76.4%, respectively. The slump remained above 155 mm, and the mass loss rate decreased by 42.6% after freeze–thaw cycles. XRD and FTIR analysis showed that the addition of FA and NS accelerated the hydration reaction process of RFC-SF, reduced the content of calcium hydroxide (CH) and refined the grain size of CH. RFC-SF had a denser microstructure and a lower calcium-silicon ratio in SEM and EDS tests.

Preparation and Properties of Double Liquid Grouting Materials (DLGMs) Used for the Regenerated Roof of a Coal Mine

Double liquid grouting materials (DLGMs) are composed of slurry A and slurry B. In response to the need for sustainable development, there is currently a focus on improving the utilization rate of resources. In this paper, industrial solid waste fly ash, slag, and ordinary Portland cement were used to prepare slurry A, while sodium silicate was used as slurry B. Slurry C was made by adding slurry B to slurry A. The mix design parameters of the DLGMs, with large amounts of fly ash, were optimized based on the response surface method. The results showed that the relative content of cement and the reactivity and morphological effect of supplementary cementitious materials (fly ash and slag) were the main factors affecting the operable time, viscosity, and stability of slurry A. The relative content of cement and the sodium silicate modulus were the main factors affecting the operable time of the DLGMs. Compared to the C30F70S0-Z3.3 group (where C, F, S, and Z represented cement, fly ash, slag, and sodium silicate modulus, respectively), the operable time of the C0F70S30-Z3.3 group increased by approximately 36 min. As the sodium silicate modulus was lowered to 2.3, the operable time of the C0F70S30-Z2.3 group increased by about 32 min compared to that of the C30F70S0-Z2.3 group. The established model and response surface can well reflect the influence of multiple factors on the properties of the DLGMs. When the mass ratio of cement/fly ash/slag in slurry A was 7.5%: 70%: 22.5%, and the sodium silicate modulus and content of slurry B were 2.8 and 10%, respectively, the 28-day compressive strength of the DLGMs can reach up to 11.3 MPa. The content of fly ash was the most significant factor affecting the 28-day compressive strength of the DLGMs, followed by the sodium silicate content. The least influential factor was the sodium silicate modulus. The XRD and SEM results showed that a large amount of Ca2+ produced by cement hydration can quickly react with [SiO4]4- in sodium silicate to form C-S-H gel. Moreover, it also promoted the hydration of C3S and C2S in grouting to produce more C-S-H gel, which was conducive to the alkali activation of slag and fly ash, resulting in a denser microstructure and hence, yielded obvious increases in the compressive strengths of the DLGMs.

Effect of alkali sulfates in clinker on hydration and hardening properties of cement incorporating SCMs

Fly ash and slag are widely used in cement production. The effect of alkali sulfates in clinker on hydration and hardening of cement blended with fly ash and slag is studied. The results of hydration heat evolution, hydrates analysis and mechanical properties indicate arcanite (K2SO4), thenardite (Na2SO4), aphthitalite (3K2SO4·Na2SO4, K3NS4) and Ca-langbeinite (K2SO4·2CaSO4, KC2S3) in clinker could activate the pozzolanic activity of fly ash and slag, facilitating the appearance of the second hydration peak in the initial hydration period, and promote the hydration and hardening properties of blended cement. The adverse effects of alkali sulfates in clinker are alleviated with the addition of fly ash and slag; this can be attributed to the dilution and filler effects of supplementary cementitious materials (SCMs), as well as the effect of the alkali sulfates activating fly ash and slag. Arcanite, thenardite and aphthitalite (K3NS4) provide a better activating effect on mortar with slag than fly ash mortar to increase compressive strength and reduce drying shrinkage when the content of alkali sulfates is less than 0.6% sodium oxide equivalent (Na2Oeq).

Effects of supplementary cementitious materials on concrete reinforcement corrosion in magnesium sulphate

Effects of supplementary cementitious materials on concrete reinforcement corrosion in magnesium sulphate

Review of supplementary cementitious materials with implications for age-dependent concrete properties affecting precast concrete

This paper presents a comprehensive review of existing research examining the effects of supplementary cementitious materials on age-dependent concrete properties with the most profound implications for precast concrete production. The review covers the physical and chemical properties of selected types of supplementary cementitious materials, concrete mixture proportions, concrete curing methods, testing procedures, and test results related to the fresh properties and strengths of a range of concrete mixtures. Although the use of supplementary cementitious materials in precast concrete products is common, the detailed information provided in this paper may facilitate more widespread use of these materials to enhance concrete properties and comply with sustainability initiatives.

The Effects of Supplementary Cementitious Materials (SCMs) on the Residual Mechanical Properties of Concrete after Exposure to High Temperatures—Review

Fire events remain a severe hazard despite significant progress in the construction industry. The high-temperature resistance of concrete structures highly depends on the properties of their ingredients. The present study provides an analytical review of the available experimental studies investigating the influence of high temperatures on the residual mechanical characteristics of concrete, namely compressive and tensile strength, as well as the modulus of elasticity. This paper primarily focuses on the influences of supplementary cementing materials, including silica fume (SF), fly ash (FA), and ground granulated blast furnace slag (GGBFS), as well as different aggregate types. The literature findings show that the mechanical characteristics of concrete are degraded dramatically due to heat-caused changes in concrete. In addition, the mechanical properties of concrete are highly influenced by the types of aggregate and the amount of supplementary cementing materials at both high temperatures and room temperature. The inclusion of FA and GGBFS improves the high-temperature resistance of concrete. However, high contents of FA and GGBFS result in adverse effects on the properties of concrete. This review will provide a basis for future studies and enhance the knowledge of the behaviour of reinforced concrete structures subjected to high temperatures.

Compressive strength, water and chloride transport properties of early CO2-cured Portland cement-fly ash-slag ternary mortars

Early CO2 curing is a promising technology for improving the strength and long-term durability of mortar and concrete as well as CO2 sequestration. However, the effects of supplementary cementitious materials (SCMs) such as fly ash and slag on the chloride transport properties of cement-based materials subjected to early CO2 curing are not clear. In this study, compressive strength, water and chloride transport behaviors of Portland cement-fly ash-slag ternary mortars subjected to early CO2 curing and subsequent lime water curing were determined. The obtained results indicated that the addition of fly ash and slag lowered the compressive strength, water and chloride ions penetration resistance of cement mortars at the late age. Regarding the mechanical and transport properties, the replacement level of fly ash and slag in early CO2-cured cement mortars should not exceed 25% when it exposure to chloride ions. Slag had less influence on the mechanical and transport properties of early CO2-cured cement mortars than fly ash due to finer particle size of the former.

Effects of supplementary cementitious materials on the durability of glass aggregate mortars

The durability performance and sustainability of concrete and mortar can be enhanced by incorporating supplementary cementitious materials (SCMs), such as fly ash, slag (SG), silica fume (SF), and metakaolin (MK). In this study, binary and ternary blends of the aforementioned SCMs were investigated to determine an optimal combination that enhances the durability of glass aggregate mortars. Compressive strength, chloride permeability, and sorptivity experiments were conducted for all mixtures at specimen ages of 28 and 90 days. Fourteen day alkali silica reaction tests were also performed to determine the expansion properties. It was determined that ternary blends of fly ash and SF effectively mitigate expansions, with mixtures containing fly ash being most effective due to its high silica (SiO2) content. Ternary blends of SG and SF were also found to be successful in reducing permeability. In addition, it was determined that optimal durability performance can be achieved with 10% MK and SF replacements.