Sustainable Self-compacting Concrete Research Articles

Development of sustainable self-compacting concrete: Replacement of sand with municipal solid waste incineration ash molten slag and recycled fine aggregate

The purpose of this study is to develop self-compacting concrete using MSWA and RA as fine aggregates, supplemented with fly ash and GGBS that can modify the workability of the concrete. To evaluate the performance of sustainable self-compacting concrete, its mechanical properties, workability, drying shrinkage, and pore structure were comprehensively analyzed. The results demonstrate the feasibility of producing self-compacting concrete by replacing 50–100 % of sand with MS and RA, as all mixes in this experiment achieved the target slump flow of 600 ± 20 mm. The compressive strength remained unaffected for MS contents below 25 %, but at 50 % MS, it was 10 % lower than that of normal concrete. The drying shrinkage deformation of all specimens was below 700 μ, meeting the requirements for practical engineering applications. Incorporating fly ash increases porosity but transforms micropores larger than 100 nm into those smaller than 100 nm. Incorporating GGBS not only reduces porosity but also converts pores of 10–100 nm into gel pores smaller than 10 nm. Additionally, the suitability of various formulas correlating compressive strength and static elasticity modulus, recommended by American Concrete Institute (ACI 363), European Practice (EN 1992), and the Architectural Institute of Japan (JASS 5), was evaluated, and appropriate formulas were determined through regression analysis.

Fresh And Hardened Properties of Binary Blend Sustainable Self-Compacting Concrete (SCC) Containing Calcined Eggshell and Silica Fume as Partial Replacement of Cement

Fresh And Hardened Properties of Binary Blend Sustainable Self-Compacting Concrete (SCC) Containing Calcined Eggshell and Silica Fume as Partial Replacement of Cement

Sustainable self-Compacting concrete with marble slurry and fly ash: Statistical modeling, microstructural investigations, and rheological characterization

The escalating generation of marble waste and the substantial carbon footprint associated with cement production pose significant environmental challenges. Thus, by substituting fly ash for supplementary cementitious material and using leftover marble waste for fine aggregate in concrete can reduce cost and carbon emissions that may lead to sustainable development. The presented paper aims to study the effect of partial substitution of marble slurry with natural fine aggregates and fly ash as supplementary cementitious material (SCM) on Self-Compacting Concrete (SCC). Polycarboxylate Ether (PCE) based superplasticizer (SP) was added in the concrete mix, to decrease the demand of higher water to binder (w/b) ratio. After developing SCC, fresh state properties and compressive strength (CS) at the curing age of 7 and 28 days were evaluated. To maximize the utilization of marble slurry and fly ash, mixture optimization was performed using the Box-Behnken Design (BBD), a robust technique within the response surface methodology (RSM) framework. Rheological analysis was performed to analyse the fresh state behaviour of the SCC with the help of the Bingham and Modified Bingham (MB) models. Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) studies were also carried out to study the behaviour of the marble slurry and fly ash in the concrete. Carbon emission and cost analysis of SCC was evaluated at different replacement level of the marble slurry and fly ash. It was inferred that marble slurry and fly ash can be used in the certain percentages without compromising any strengthen and flowability properties of the SCC. The rheological behaviour also confirmed that linear and nonlinear behaviour of SCC in the certain mix proportion may results in the formation of the stable SCC. The analysis of cost and carbon emission confirmed that sustainable SCC mixture achieved substantial reductions of 21.44 % in cost and a remarkable 47.71 % decrease in carbon dioxide (CO2) emissions compared to conventional concrete.

Characteristic evaluation and environmental validation of self-compacting concrete containing sandstone slurry waste for sustainable usage.

This study aims to understand the impact of concrete ingredients on the environment. To analyze the effect of, three significant indexes have been taken into consideration, which are embodied carbon dioxide index (e-CO2), embodied energy consumption (e-energy), and embodied resource consumption (e-resource) index. The life cycle assessment (LCA) methodology has considered veto comprehending the probable application of sandstone waste in the form of a slurry (Sslurry) and powder (Spowder) for the development of self-compacting concrete (SCC). This study can be proven beneficial to evaluate the potential adverse effects from environmental and energy perspectives. One reference mix and eighteen design mixes of SCC have been designed and developed to perform an experimental program. An environmental impact comparison of the "hybrid" SCC was performed using the OpenLCA life cycle analysis software with Ecoinvent LCIA methods. The outcomes of this experimental program reveal that the partial replacement of pozzolana Portland cement (PPC) with Sslurry can reduce e-CO2 emission along with the e-energy and e-resource parameters. When Spowder was used as the partial substitution of fine aggregate (FA), only the e-resource index decreased, and e-CO2 and e-energy increased. Minimalist impact on the environment has been noticed when SCC is prepared with Sslurry and Spowder. A detailed LCA analysis study justifies the utilization of Sslurry and Spowder in SCC, which exhibits encouraging results concerning strength and quality. Hence, it was observed that Sslurry and Spowder in developing green and sustainable SCC with moderate strength characteristics are beneficial from an environmental impact perspective.

Efficiency of self-compacting concrete made with variable sustainable cementitious materials: A TOPSIS algorithm approach

The use of supplementary cementitious materials as a partial replacement for cement is taking the lead in the concrete production industry. Being known as by-products from various manufacturing properties, concrete produced with such materials is considered a sustainable alternative to normal concrete. Three different by-product materials have been investigated in this study for the production of sustainable self-compacting concrete (SCC), namely, ground granulated blast furnace slag (GGBS), fly ash (FA), and silica fume (SF). Compressive strength, production cost, and global warming potential (GWP) were the main testing parameters for the mixes' performances. Multi-criteria decision-making algorithm was implemented using the TOPSIS model to investigate the ultimate performance of those SCC mixes considering all tested parameters simultaneously. Results showed the best SCC performance can be attained when using about 60 % of GGBS as a partial replacement for cement.

Design automation of sustainable self-compacting concrete containing fly ash via data driven performance prediction

Self-compacting concrete (SCC) is a highly flowable and segregation-resistant material, effectively facilitating proper filling and ensuring exceptional structural performance in confined spaces. Incorporating fly ash as a supplementary cementitious material in SCC mixtures yields numerous benefits, including enhanced cost-effectiveness in construction and the advancement of environmental sustainability. Nevertheless, the addition of fly ash in SCC poses significant challenges in modelling and predicting the properties of SCC due to lack of understanding of its influence on material rheology and bonding. It is therefore desirable to develop more appropriate machine learning approach to compliment the large scale and costly laboratory-based experiments. This paper presents four well trained supervised machine learning models for the prediction of fresh and hardened properties of SCC containing fly ash: support vector machine (SVM), decision tree, random forest, and artificial neural network (ANN). Training datasets gathered from publicly available existing relevant literature, were analysed and processed prior to shape the required machine learning models. Optimization strategies of hyperparameters were also implemented for each model. To evaluate the performance of these machine learning models and to compare their accuracy, regression error characteristic curves and Taylor diagrams were utilized. The findings reveal that all models demonstrate promising results, with the random forest model outperforming the others in predicting SCC properties with higher accuracy. This underscores the potential of random forest algorithms in accurately modelling and predicting the properties of fly ash-infused SCC. Finally, a data driven implementation framework has been developed, thereby offering robust and logical strategy for experimental designs and guidance for developing sustainable SCC.

Modeling the Properties of Sustainable Self-Compacting Concrete Containing Marble and Glass Powder Wastes Using Response Surface Methodology

This study aims to apply the response surface methodology (RSM) to develop a statistical model that predicts and models the performance of both the fresh and hardened properties of self-compacting concrete (SCC). RSM was used to model processes involving three variables: the water/binder ratio, and the percentages of waste marble, and glass powder. Tests, including slump flow diameter, sieve stability, and L-box, were carried out to evaluate the fresh properties of the self-compacting concrete; compressive strength was analyzed at 7, 28, and 90 days. Statistical significance was only observed in the water/binder ratio for both the slump flow and sieve stability tests. Furthermore, these results indicate that the models used in the compressive strength tests demonstrate a high statistical significance for all ages. The findings suggest that incorporating waste marble powder (MP) and glass powder (GP) in SCC necessitates a significant amount of superplasticizer to counteract the workability loss, and it improves the compressive strength of SCC. The coefficients analyzed using the RSM approach validate its effectiveness as a predictive tool for determining the hardened properties of self-compacting concrete.

Rheology, Mechanical Properties and Shrinkage of Self-Compacting Concrete Containing Cement Kiln and By-Pass Filter Dust

Self-compacting concrete (SCC) is a high-quality construction solution, combining high fluidity, passing and filling ability with improved mechanical properties and durability. In the present study, the effect of incorporating alternative waste materials, such as two by-products of the cement industry, namely cement kiln dust (CKD) and by-pass dust (BPD) into SCC, as a partial replacement for traditional filler material, was investigated. The produced compositions were compared with reference mixtures containing exclusively marble powder (MP), as a filler. A series of tests encompassing specific test methods for wet SCC, compressive, flexural and tensile-splitting strength tests, as well as drying-shrinkage determination, were undertaken to evaluate the quality of the produced SCC in terms of fresh and hardened properties. The use of alternative fine-filler materials resulted in a high-performance sustainable SCC, of low cement content. To be precise, incorporating CKD into the SCC enhanced its rheological behavior and marginally improved its mechanical properties, while the use of BPD led to SCC mixtures of adequate rheological characteristics, coupled with significantly improved mechanical and physical properties.

Eco-efficiency evaluation of sustainable self-compacting concrete using magnesite mine waste

Utilization potential of industrial by-products/wastes as construction material requires adequate workability, strength and other required properties as specified by standard codes of practice and certain sustainability criteria. Coal combustion byproduct (fly ash) and mine waste are a few of the abundantly available wastes that create a challenging task in their disposal with the current practice of dumping on-sites and landfilling. This study enumerates the suitability of utilizing magnesite mine wastes in self-compacting concrete (SCC) as binder and aggregate replacements by considering the evaluation factors such as fresh, hardened properties, life cycle assessment (LCA) and eco-efficiency. The results from the experimental investigation revealed that aggregate blended SCC performed well in terms of both fresh and mechanical properties, while cement blended mixtures exhibited satisfactory results. Additionally, fly ash and magnesite mine waste substantially reduced CO2 emissions and costs with added strength benefits. Eco-efficiency evaluation of mine waste blended SCC reported up to 75% higher efficiency than conventional SCC.

Effect of various powder content on the properties of sustainable self-compacting concrete

This research goal is to evaluate the characteristics of glass powder (GP), quartz powder (QP), and limestone powder (LP) as Supplementary Cementitious Materials (SCMs) to replace cement content in terms of fresh and hardened properties of Self-Compacting Concrete (SCC) for sustainable building construction. Moreover, the obtained results were modeled using a soft computing approach. This investigation created ten mixtures incorporating varying percentages of GP, QP, and LP by replacing cement at about 0 %, 10 %, 20 %, and 30 %, respectively. The slump flow and J-ring tests were done to observe how SCMs affected the properties in fresh condition. In addition, the mechanical properties and pore structure configuration of the specimens were investigated. It was observed that GP and LP positively affected the fresh properties, increasing the mixes flowability by up to 8 %. Moreover, 20 % GP was able to enhance the compressive strength by 7 % by improving the pore structure of the cement matrix, which was confirmed by the mercury intrusion porosimetry analysis. Finally, the built machine learning models indicated good accord with test outcomes for Artificial Neural Network (R2 = 0.95) and could be applied to calculate the compressive strength of concrete containing GP, QP and LP for construction housing sector.

Efficacy of Fire Protection Techniques on Impact Resistance of Self-Compacting Concrete

The present research investigates the behaviour of sustainable Self-Compacting Concrete (SCC) when subjected to high temperatures, focusing on workability, post-fire impact resistance, and the effects of fire protection coatings. To develop environmentally friendly SCC mixes, Supplementary Cementitious Materials (SCM) such as Fly Ash (FA), Ground Granulated Blast Furnace Slag (GGBFS), and Expanded Perlite Aggregate (EPA) were used. Fifty-six cubes and ninety-six impact SCC specimens were cast and cured for testing. Fire-resistant Cement Perlite Plaster (CPP) coatings were applied to the protected specimens, a passive protection coating rarely studied. SCC (unprotected and protected) specimens, i.e., protected and unprotected samples, were heated following the ISO standard fire curve. An extensive comparative study has been conducted on utilising different SCMs for developing SCC. Workability behaviour, post-fire impact resistance, and the influence of fire protection coatings on sustainable SCC subjected to high temperatures are the significant parameters examined in the present research, including physical observations and failure patterns. The test results noted that after 30 min of exposure, the unprotected specimen exhibited a significant decrease in failure impact energy, ranging from 80% to 90%. Furthermore, as the heating duration increased, there was a gradual rise in the loss of failure impact energy. However, when considering the protected CPP specimens, it was observed that they effectively mitigated the loss of strength when subjected to elevated temperature. Therefore, the findings of this research may have practical implications for the construction industry and contribute to the development of sustainable and fire-resistant SCC materials.

Mechanical and Durability Properties of Sustainable Self-compacting Concrete with Waste Glass Powder and Silica Fume

Environmental protection approach has caused to ignore the conditions and the possibility of using solid waste as a substitute for concrete. In this research, the effect of glass powder in percentages of 0-30 (in steps of 7.5%) and micro-silica (10% as a constant) as a substitute for cement is investigated on efficiency, compressive strength, tensile strength, and bending strength. surface water absorption, capillary water absorption, and freeze/thaw cycle are paid. The results showed that the use of glass powder leads to increases the fluidity and properties of fresh concrete. The mechanical parameters decrease slightly when 30% of cement is replaced with glass powder.

Predicting the behaviour of self-compacting concrete incorporating agro-industrial waste using experimental investigations and comparative machine learning modelling

This study examines the effects of the silica fume (SF) and fly ash (FA) together as a binary replacement of cement on the behaviour of self-compacting concrete (SCC) using experimental investigation and application of various machine learning (ML) models developed for this study. The SF and FA were used in combination of 25/75, 50/50, 75/25 proportions with 5%, 10% and 15% cement replacement, respectively, at 3,7, 14- and 28-days curing. In first phase, unit weight, workability, compressive strength (CS) and dimensional stability of the sustainable SCC were investigated through experimental testing. The experimental results revealed that the fresh properties of SCC, at all replacement levels and combination of SF and FA, were remained within the range of the standard values. At the same replacement percentages, the combination of SF/FA of 50/50 was more effective than the other two combinations of SF/FA at the same dosage levels and at all the ages of SCC. The CS was improved by 17% at 15% replacement level when SF and FA were blended at the combination of 50/50. The second phase of this study differentiate this research from the past literature. The collection of modelling algorithms used in this study have never been applied to this kind of data to provide a comparative analysis over two different datasets. The ML modelling was performed using Neural Network Regression (NNR), Decision Forest Regression (DFR), Linear Regression (LR) and Bayesian regression (BR). Initially, the dataset achieved through the experimental investigations performed in this study was modelled. The models efficiently predicted the CS of sustainable SCC when compared with experimental results. Later, the dataset available in the literature was also used to verify the accuracy of the proposed ML models. Based on the findings, the best performing algorithms were LR and NNR, both with R2 = 0.9, that highlights the optimum and enhanced performance of the ML modelling over other numerical methods.

Using marble waste as a partial aggregate replacement in the development of sustainable self-compacting concrete

Increased population growth and industrial development have increased production in various industries, resulting in increased waste production. Increasing consumption of non-renewable resources poses an inherent risk to future generations. In order to reduce the consumption of these valuable resources, a variety of methods can be used, one of which is the use of waste produced by various industries. This research investigated the feasibility of employing waste from marble mining byproducts to make structural concrete. This study replaced various percentages of marble with fine aggregates to determine their effects on compressive strength, bending strength, impact behavior, and water absorption of sustainable self-compacting concrete (SCC). Regarding the effects of recycled marble aggregates on mechanical properties, it has been discovered that substituting marble waste with sand can increase compressive and flexural strength. It has been determined, via testing on disk samples, that the amount of steel fibers have a much greater effect on the impact resistance of the specimens than the amount of recycled components. Fiber bridging has been shown to significantly affect the final strength of specimens containing fibers and the number of blows required for the first surface fracture to appear in fiber-containing specimens. This is in comparison to the sample that served as the reference. In addition to this, increasing the replacement percentage of recycled aggregates in the specimens causes them to have a greater resistance to the impact loads applied to them. In examining the effect of replacing marble aggregates on water absorption, it was found that no specific trend could be indentified. Based on the findings, it was determined that SCC with recycled marble aggregate performed satisfactorily.

Evaluation of the Rheological and Durability Performance of Sustainable Self-Compacting Concrete

Self-Compacting Concrete (SCC) is a special concrete that can flow easily across congested reinforcements. Also, it is easy to work with and does not segregate. The present investigation aims at the design and development of sustainable SCC with the employment of industrial by-products such as Fly Ash (FA), Ground Granulated Blast Furnace Slag (GGBFS), and Expanded Perlite Aggregate (EPA). Four SCC mixes were developed to attain a target strength of 30 MPa. Workability tests (slump flow, J-ring, and V-funnel tests) were performed following the EFNARC guidelines to ensure fresh SCC properties. Detailed experiments were conducted to evaluate the durability characteristics of the developed SCC, such as water absorption, sorptivity, acid attacks (sulphuric, nitric, sulphate, and chloride), the Rapid Chloride Penetration Test (RCPT), and finally, the elevated temperature test. Weight loss, strength loss, and physical observations of the acid and temperature effects of SCC mixes were evaluated. Also, the study focuses on the cost and sustainable index of SCC mixes and compares them with OPC mixes. From the experimental data analysis, it was observed that the developed SCC showed excellent physical and mechanical properties with a considerable reduction in cement content. SCC specimens with FA and EPA exhibit excellent acid and temperature resistance. Following the sustainable analysis, it was noted that SCC mixes reduce about 15–17.2% of carbon emissions compared to the OPC mix.

Development of Eco-friendly Self-compacting Concrete Using Fly Ash and Waste Polyethylene Terephthalate Bottle Fiber

This study aims to utilize fly ash and waste PET bottles for producing more sustainable self-compacting concrete (SCC) with better mechanical strength. Fly ash is utilized as a supplementary cement material and waste PET bottles as fiber reinforcement to improve its flexural strength and achieve the targeted compressive strength. The experimental works were conducted on eight variations using 80 specimens, divided into two main groups of partial cement replacement using 0% and 15% fly ash by weight. The two variants are added with PET fiber based on the volume fractions of 0%, 0.25%, 0.50%, and 0.75%. Fresh concrete was tested using the slump flow method (T50) and the Visual Stability Index (VSI) based on ASTM 1611. The hardened concrete tests are conducted after 56 days and include testing the concrete's compressive strength, flexural strength, and ultrasonic pulse velocity. Test results showed that the presence of PET fiber in the SCC mix decreased its flowability. However, when added up to 0.75%, the mixes still meet the flowability requirements of fresh-state SCC. PET fiber addition tends to reduce the compressive strength, whereas the reduction in compressive strength of SCC with PET fiber without fly ash is insignificant. However, in SCC that uses fly ash, the addition of PET fiber causes a significant decrease in its compressive strength. Adding PET fiber into SCC mixes can increase flexural strength, both for the two variants: SCC without fly ash and SCC with fly ash. It can be concluded that PET waste fiber with an aspect ratio of 40 can be added up to 0.5% for SCC without fly ash and up to 0.25% by volume fraction for SCC with fly ash addition. The ultrasonic pulse velocity test results have an excellent tendency to predict the concrete's compressive and flexural strengths. Therefore, the UPV test can be applied for the non-destructive test evaluation of PET fiber-reinforced SCC. Doi: 10.28991/CEJ-2023-09-02-014 Full Text: PDF

Long‐term behavior of sustainable self‐compacting concrete with high volume of recycled concrete aggregates and industrial by‐products

AbstractThe addition of recycled concrete aggregates together with industrial by‐products for the concrete production is an effective solution to the environmental problems in terms of excess waste materials and massive nonrenewable natural resources consumption. This article investigates the long‐term behavior and microstructure of sustainable self‐compacting concrete (SCC) by substantially substituting natural coarse aggregate with recycled coarse aggregates (RCA) and cement with supplementary cementitious materials (SCM). The influences of RCA and SCM content as well as SCM combination type (fly ash, ground granulated blast furnace slag and/or silica fume) on the mechanical properties and long‐term deformation of recycled aggregate SCC (RA‐SCC) were assessed in detail. Furthermore, scanning electron microscope and x‐ray diffraction were implemented to justify the reasons for improvement on mechanical properties and long‐term behavior of RA‐SCC. The results indicate that the addition of RCA reduces the compressive strength and elastic modulus of RA‐SCC, and increases the creep and shrinkage deformations. However, incorporating SCM with a combination of fly ash, ground granulated blast furnace slag and silica fume compensates for the detrimental effect of RCA and makes considerable improvement in strength and reduction in the long‐term deformations. Microstructure analysis confirms the reasons of improvement, which is mainly attributed to the addition of SCM by adopting a combination type, resulting in a more compact microstructure such as stronger interfacial transition zone. Based on the experimental results, the correction factors of RCA and SCM were introduced in conjunction with fib Model Code 2010 model to evaluate the creep coefficient of RA‐SCC.

Optimum characteristics of plastic fibres for sustainable self-compacting concrete SCC

The main aim of this research is to optimize various characteristics of Polyethylene terephthalate PET fibres in a sustainable self-compacting concrete in terms of volume fraction Vf, aspect ratio Ar and method of surface treatment. In the first stage, the performance of fibre-reinforced self-compacting concrete was analysed in terms of main fresh and hardened properties. Nine different SCC mixtures were designed using three different ratios of Vf and Ar. The fresh tests were evaluated through the examination of the slump flow and T500 while the hardened tests include compressive and splitting tensile strength test. The optimal mixture was selected based on a statistical program (Minitab19) for the next stage. The optimized mix in stage two is selected to be a control mix in addition to other two mixtures with PET fibres treated chemically (NaOH solution), and mechanically (surface roughness). The fresh tests in this stage include slump flow, T500mm, L-box, sieve segregation whereas the hardened tests include compressive, splitting tensile, flexural, impact strength, porosity, and water absorption. The multi-objective optimization results from first stage indicated that the optimum Vf and Ar for PET fibres, to achieve the optimum performance in terms of the tested properties and the partitioning of sustainability aspects, were 0.7% and 24.4 respectively. The results of the two modifications used for PET fibres reduced the fresh properties slightly (flow, L-box, T500, sieve segregation) yet they were within the specification limits for SCC. However, the mechanical and related durability properties (strength, tensile, flexural, impact, less porosity, less absorption) were increased considerably. It can be deduced that treatment of PET fibres by increasing the roughness surface with the optimum characteristics of PET fibres from stage one, in terms Vf and Ar, can give the best performance.

Shrinkage and Creep of Sustainable Self-Compacting Concrete with Recycled Concrete Aggregates, Fly Ash, Slag, and Silica Fume

Shrinkage and Creep of Sustainable Self-Compacting Concrete with Recycled Concrete Aggregates, Fly Ash, Slag, and Silica Fume

Implementation assessment of calcined and uncalcined cashew nut-shell ash with total recycled concrete aggregate in self-compacting concrete employing Bailey grading technique

The present study concentrates on the performance evaluation of calcined and uncalcined cashew nut-shell ash (UCCNA and CCNA) with treated total recycled concrete aggregate (TRCA) in self-compacting concrete. The achievement of sustainable self-compacting concrete (SCC) is possible by the implication of four stages, which includes TRCA treatment process, gradation selection process through Bailey aggregate grading technique, by considering TRCA replacement percentage with an increment of 25% and up to 100% and by considering UCCNA or CCNA replacement with an increment of 5% and up to 20%. Hardened and fresh properties of SCC have been performed and analyzed based on the compliance requirements of SCC. In addition finding results through microstructure assessment was in line with the findings of the hardened and fresh properties of SCC. In addition, quality and dynamic instability assessments of SCC were analyzed through ultrasonic pulse velocity and drying shrinkage aspects. Besides CO2, the emission rate and the efficiency rate of SCC, composites were analyzed in detail. Overall findings revealed that CCNA-based SCC mixes performed effectively than UCCNA-based SCC; specifically, incorporation of 75% of TRCA with 15% CCNA was found to be optimal. But with regard to shrinkage performance UCCNA found to be better by imputing less shrinkage compared to CCNA-based SCC mixes. Further with regard to efficiency rate of SCC composites revealed the gain of maximum efficiency of about 0.156 MPa/kg CO2/m3 and 0.160 MPa/kg CO2/m3 for 15% and 20% CCNA-based SCC mixes.