Mechanical Properties Of Self-compacting Concrete Research Articles

Performance of Various Types of Bacillus Bacteria on the Rheology and Mechanical Properties of Self-Compacting Concrete

Performance of Various Types of Bacillus Bacteria on the Rheology and Mechanical Properties of Self-Compacting Concrete

Self-compacting concrete using molybdenum mineral tailings: materials and mechanical property

Recycling mineral tailings poses significant challenges, but one effective solution is their incorporation into self-compacting concrete (SCC) mixtures. This research explores the material and mechanical properties of SCC by integrating mineral tailings at three different ratios: 10%, 20%, and 30%. The primary aim is to determine the optimal replacement ratio that preserves key characteristics such as flowability and viscosity. To assess the material properties of fresh SCC, we conduct various tests, including rheological, V-funnel, U-box, and air content tests. These evaluations focus on how the addition of mineral tailings at different levels impacts flowability and viscosity. In terms of mechanical performance, we analyze compressive strength relative to the increasing proportion of mineral tailings. The results indicate that higher proportions of mineral tailings negatively affect flowability and viscosity. As a result, the optimal replacement ratio for mineral tailings is identified as up to 20% of the total cement content. These findings suggest that mineral tailings can effectively replace conventional cement, making them a promising option for producing environmentally friendly self-compacting concrete.

Basic Mechanical Properties of Self-Compacting Concrete Prepared with Aeolian Sand and Recycled Coarse Aggregate

To protect the environment and reduce the consumption of natural resources, this study investigated the performance of self-compacting concrete (SCC) utilizing aeolian sand (AS) as a replacement for fine aggregate and recycled coarse aggregate (RCA) as a replacement for natural coarse aggregate. Twelve mixing ratios were prepared, with AS replacement ratios at 0, 20%, 40%, and 60% and RCA replacement ratios at 0, 25%, and 50%. The evaluation primarily focused on workability, uniaxial compressive strength, split tensile strength, stress–strain curve, modulus of elasticity, and axial compressive strength. The results indicated that both AS and RCA can enhance the performance of SCC at appropriate replacement ratios, and a 20% AS and 50% RCA replacement ratio significantly improved the performance of SCC. In addition, the effects of AS and RCA replacements on SCC were evaluated by several performance indexes, which provides a basis for subsequent experimental studies and demonstrates the feasibility of incorporating AS and RCA into SCC.

Effects of Volcanic Tuff Use on the Rheological and Mechanical Properties of Self-Compacting Concrete

The rise in demand of concrete products has led to overexploitation of river sand the main fine aggregate in concrete resulting in major environmental degradation. As a result, researchers have focused their efforts on developing eco-friendly concrete using alternative renewable materials like volcanic tuff and other natural pozzolana types. This study therefore, aims at investigating the use of Kenyan, Kitengela volcanic tuff as a partial replacement of river sand in self-compacting concrete, and determining the effects it will have on the rheological and mechanical properties of the self-compacting concrete. The study involved partially replacing river sand with volcanic tuff in percentages of 0%, 2.5%, 5%, 7.5% and 10% and carrying out rheological tests (V-funnel test, L-box test, T-500 test and J-ring test) on fresh concrete and mechanical tests (compressive strength and tensile strength tests) on hardened self-compacting concrete on days 7, 14, and 28 to determine the effects of volcanic tuff on properties of both fresh and hardened self-compacting concrete. There was a general decrease in rheological properties (flow and passing abilities) of self-compacting concrete with increase in volcanic tuff percentage replacement from 0 % to 10%, with least flow and passing abilities recorded at 10% replacement. Similarly, increase in volcanic tuff percentage replacement led to decrease in both compressive and tensile strength of self-compacting concrete with lowest values recorded at 10% volcanic tuff replacement.

Investigation of mechanical properties of self-compacting concrete induced with zeolite and graphene oxide

Investigation of mechanical properties of self-compacting concrete induced with zeolite and graphene oxide

Enhancing sustainability in self-compacting concrete by optimizing blended supplementary cementitious materials

Within concrete engineering, the uptake of self-compacting concrete (SCC) represents a notable trend, delivering improved workability and placement efficiency. However, challenges persist, notably in achieving optimal performance while mitigating environmental impacts, particularly in cement consumption. However, simply reducing the cement content in the mix design can directly compromise the structural-concrete requirements. Towards these challenges, global trends emphasize the utilization of appropriate waste materials in blended concrete. This study explored a promising strategy by integrating supplementary cementitious materials (SCMs) to contribute to the United Nations' Sustainable Development Goals (SDGs) in addition to the engineering contributions. It suggests an optimal combination of Metakaolin (MK) and Limestone Powder (LP) to partially substitute cement. The research methodology employs the response surface method (RSM) to systematically explore the ideal ingredient ratios. Through a comprehensive analysis of orthogonal array of 16 mixes, encompassing both mixture and process variables, this study aims to explain the effects of MK and LP addition on the rheological and mechanical properties of SCC with varying cement replacement levels. In terms of mixture constituents, the total composition of cement, MK, and LP was fixed at 100%, while coarse aggregate (CA), fine aggregate (FA), and the water-to-binder ratio were held as process variables. In order to assess the rheological properties of the mix-design, various tests including slump flow, L-box, and sieve segregation were conducted. Additionally, to evaluate mechanical strength, samples were tested for compressive strength at both 7 and 28 days. Findings from the experiments reveal higher concentrations of MK result in reduced workability and hardened properties. Through RSM-based designed experimentation covering both rheological and mechanical aspects, it is observed that the optimal cement replacement level lies between 40 and 55%. The findings of this study contribute to the advancement of sustainable and structurally robust concrete practices, offering insights into the optimal utilization of SCMs to meet both engineering requirements and environmental sustainability goals.

Influence of Extra-Short Extra-Fine Steel Fibers on Mechanical Properties of Self-Compacting Concrete with Single-Doped Fly Ash

This study assesses the influence of extra-short extra-fine steel fibers on the performance of self-compacting concrete (SCC) modified with fly ash. Replacing standard steel fibers with volume fractions ranging from 0%, 1.5%, 3%, 5% and 6%, the study optimizes the mix design for enhanced workability and mechanical properties. The findings reveal that, although the addition of steel fibers had a negative effect on the flowability, the cohesion is significantly improved, providing a basis for a significant improvement in the mechanical properties. The optimal fiber content is identified at 5%, achieving the highest compressive strength of 71.7 MPa, split tensile strength of 8.2 MPa, and flexural strength of 12.8 MPa at 28 d. However, further increases in fiber content beyond 5% lead to a deceleration in compressive and splitting tensile strength improvement and a 27.5% drop in flexural strength at 28 d. The study also emphasizes the good dispersion within the concrete, which helps to enhance its ductility and crack resistance, to some extent.

The Effects of Waste Ceramic Powders and Waste Glass Powders on the Rheological and Mechanical Properties of Self-Compacting Concrete

Two key axes dominated this experimental research. The first was developing self-compacting concrete from ceramic waste powder (CWP) and glass waste powder (GWP), which met and followed the recommended European specification and guidelines for self-compacting concrete (EFNARC) standards. The second axis indicated the self-compacting concrete's rheological and mechanical performance. Sixteen different mixtures were produced using supplementary cementitious materials (SCMs) to replace cement partially. The replacement levels of SCMs were 5%, 10%, and 15% (by weight of cement), divided into three series: Series A (containing ceramic waste powder), Series B (containing glass waste powder), and Series C (containing combinations of ceramic waste powder and glass waste powder). The SCC rheological properties for all mixtures with different levels of SCMs replacement in the mixture gradually decreased as the substitution ratios increased. The reduction in flowability for substitution, ranging from 5% to 35%, was approximately 0% to 12%, respectively. However, the reduction was insignificant; the fresh properties remained within the limits specified by EFNARC. Regarding the mechanical properties, at an early age, the strength of mixtures decreased with increasing alternative ratios. However, after 90 days, the strength increased by about 11% and 9% of the compressive and flexural strengths, respectively, over the control mix, indicating that SCMs improve the concrete strength over time and are suitable to contribute to an eco-friendly concrete industry without compromising strength.

Effect of combination between hybrid fibers and rubber aggregate on rheological and mechanical properties of self-compacting concrete

Rubber aggregate recycled from waste tires are added to self-compacting concrete to improve some of its properties, such as durability, toughness, and concrete resistance to impact and vibrations. In this study, modified hybrid rubberized self-compacting concrete (SCC) was produced by utilization of recycled tire rubber aggregate, plastic waste (PET), and steel fibers. Rubber was used as a partial substitute for sand, with only 10%, while the fibers were utilized in two different proportions of 0.25% and 0.35% (volume). Several tests were achieved to evaluate the rheological properties of the modified hybrid fiber rubberized SCC such as slump flow, T500, V-funnel, L-box, and segregation resistance. In addition, the hardened properties such as density, compressive, tensile strengths, and modulus of elasticity were evaluated. Microstructural evaluation of rubberized mixes was conducted. The results showed that the addition of rubber aggregate at 10% content reduces the rheological properties of SCC. The T500 mm was influenced significantly up to 15% increase. Moreover, compressive strength decreased by about 14% at same amount of rubber aggregate, while the addition of hybrid fibers improves the mechanical properties despite the negative effect on the rheological properties of rubberized SCC. The tensile strengths increased significantly by the inclusion of 0.35% hybrid fibers. The positive action of the two types of fibers led to this increase. The combination of rubber aggregate and the hybrid fibers in SCC could affect its mechanical properties positively by balancing the weakness in strength due to the lack in of bonding between rubber aggregate and cement paste and to avoid the severe deterioration in tensile strength, improve the ductility, and enhance the energy absorption capacity, especially for members subjected to earthquake effects.

Effect of waste PET fibre on rheological and mechanical properties of self-compacting concrete

Effect of waste PET fibre on rheological and mechanical properties of self-compacting concrete

Properties of High-Content Micro-Steel Fiber Self-Compacting Concrete Incorporating Fly Ash and Slag Powder Performance Study

The addition or substitution of various gel materials in cement-based composites has been proven to be an effective approach in enhancing the performance of concrete. Current research focuses mainly on enhancing the toughness of concrete, but lacks discussion on the performance of alternative gel materials. Therefore, this study aims to explore the effects of partially substituting cement with fly ash and slag powder as gel materials, while incorporating a high volume fraction of micro-steel fibers (6%), on the workability and mechanical properties of self-compacting concrete. By means of rigorous experimental investigation and meticulous analysis, we comprehensively assessed the workability characteristics of self-compacting concrete, encompassing critical aspects such as filling ability, cohesion, and permeability. Additionally, we conducted an extensive evaluation of the mechanical attributes of self-compacting concrete, encompassing vital parameters, such as compressive strength, axial compressive strength, splitting tensile strength, and flexural strength. Last but not least, through a holistic integration of workability and mechanical properties, we conducted a comprehensive performance evaluation of self-compacting concrete incorporating a synergistic blend of fly ash, slag powder, and micro steel fibers. The experimental results indicate that the composite addition of fly ash and slag powder in self-compacting concrete, while compatible with up to 6% micro-steel fibers, leads to a decrease in concrete workability and an increase in cohesiveness due to the addition of micro-steel fibers. Moreover, fly ash predominantly influences the tensile properties of concrete, while the addition of slag powder significantly affects the compressive and flexural properties of concrete. Additionally, the addition of micro-steel fibers significantly improves the overall mechanical properties of concrete.

Effect of Fire Flame on Some Mechanical Properties of Self-Compacting Concrete

Effect of Fire Flame on Some Mechanical Properties of Self-Compacting Concrete

Ai-guided proportioning and evaluating of self-compacting concrete based on rheological approach

Self-Compacting Concrete (SCC) has gained significant popularity due to its exceptional workability performance. However, designing SCC poses more challenges than ordinary concrete, as it must fulfill requirements for filling ability, passing ability, and segregation resistance. Regrettably, existing test techniques lack the ability to simultaneously evaluate all these properties, and relying on experiential knowledge and cognition without tangible physical meaning. Although rheology examines the flow and deformation of fluid materials and is closely related to SCC’s properties, the relationship between SCC composition, rheology, and properties remains unclear due to the complexity of the factors involved and the absence of effective tools. This study introduces a novel approach by utilizing a random forest algorithm to create multiple interpretable machine learning models for predicting the rheology, workability, and mechanical properties of SCC. Additionally, SHapley Additive exPlanation (SHAP) and Partial Dependence Plot (PDP) methods were integrated with the models to analyze how SCC composition impacts its properties by altering the rheology of the mixture. The models exhibit high accuracy in predicting both rheology and SCC properties (R2 = 0.93 ∼ 0.98, Index of Agreement = 0.92 ∼ 0.99). According to the SHAP and PDP analysis, yield stress and plastic viscosity were negatively correlated with slump flow, L-box ratio, and segregation rate, while exhibiting a positive correlation with V-funnel time and strength. Furthermore, the dependence of the segregation rate on yield stress was observed to be stronger at relatively low yield stress levels (below 40 Pa). These models provide valuable insights for designing and evaluating SCC mixtures tailored to specific requirements. Additionally, the study explores underlying mechanisms and offers guidelines for proportioning SCC in different design scenarios. The findings contribute to the advancement of SCC technology and have significant implications for the construction industry.

Properties and durability of self‐compacting concrete incorporated with nanosilica, fly ash, and limestone powder

AbstractThis research focused on finding the effect of nanosilica (NS) on the properties of self‐compacting concrete (SCC). NS in various proportions of 1%, 2%, 3%, 4%, 5%, 6%, 8%, and 10% was added to SCC with 10% silica fume (SF) or 10% fly ash (FA) by weight of cement to improve the properties of SCC. While the limestone powder (LSP) was used at a fixed supplementation of 15% by cement weight for all mixes. Fifteen SCC mixtures were designed based on the European guidelines for self‐compacting concrete. The properties of fresh SCC were evaluated by several tests of the slump flow, slump T50, V‐funnel, V‐funnel T5min, L‐box J‐ring, and fill box. Meanwhile, several tests evaluated SCC's mechanical properties, including compressive strength, split tensile strength, flexural strength, bond strength, and modulus of elasticity. Moreover, the permeability properties of SCC were evaluated by water permeability and air‐content tests. The effect of applying high temperatures (100–800°C) on the compressive strength of SCC containing NS with cementitious materials (SF, FA, and LSP) was also evaluated. Results showed that adding 3% NS with 10% SF and 15% LSP by weight of cement can be used to achieve the best mechanical properties of SCC. The SFNS3 mixture achieved the highest mechanical properties of 75.1, 11.9, and 41,300 MPa for compressive strength, bond strength, and modulus of elasticity tests. While the results for the slump flow, slump T50cm, and fill box were 680 mm, 6 s, and 93%.

Investigation of the mechanical properties of self-compacting concrete containing recycled steel springs; experimental and numerical investigation

Improving the performance of concrete on the one hand and preventing harmful effects on the environment, on the other hand, has caused that in this paper, the effect of adding the galvanized low carbon steel springs with different diameters, pitches and mixing percentages on the mechanical properties of the self-compacting concrete (SCC) is investigated. For this purpose, springs with diameters of 8, 12 and 16 mm, wire thickness of 0.8 mm, and two, four and six pitches in percentages of 0.2 and 0.4 were added to the SCC. Then, the compressive, tensile and flexural strength tests were performed on the specimens. The results indicated that the use of a 12 mm-diameter spring increased the compressive, tensile and flexural strengths by 29, 52 and 36%, respectively, but surprisingly, the inclusion of a 16 mm-diameter spring did not affect the mechanical properties. Moreover, it was found that the diameter of the springs is the most effective parameter on the concrete strength and the number of spring pitches cannot solely cause an increase or decrease in the strength. After performing the experimental tests, the data was collected to predict the mechanical properties of the SCC using Gene Expression Programming (GEP). Then, the proposed equations were validated. The numerical results indicated that the relative errors of the compressive, tensile, and flexural strength models were less than 10%, which proved the high capability of the Genetic Algorithm (GA).

Influence of fly ash, copper slag, plastic waste, and recycled aggregate on the fresh and mechanical properties of self-compacting concrete using Taguchi technique

Influence of fly ash, copper slag, plastic waste, and recycled aggregate on the fresh and mechanical properties of self-compacting concrete using Taguchi technique

An Explorative Study into the Influence of Different Fibers on the Spalling Resistance and Mechanical Properties of Self-Compacting Concrete after Exposure to Elevated Temperatures

This study aims to explore the impact of different fibers on the explosive spalling resistance, residual compressive strength, residual flexural tensile strength, and mass loss of self-compacting concrete (SCC) after heating to elevated temperatures. The fiber types, fiber contents, and target temperatures are selected as the tested variables. Steel fibers (SF), polypropylene fibers (PF), and their combination are used to improve the fire resistance of SCC. Then, the specimens are tested after exposure to different target temperatures varying from 200 °C to 1000 °C and cooling down to room temperature naturally. The obtained results reveal that PF can effectively prevent explosive spalling in the SCC. Moreover, it was found that the temperature of 400 °C is a critical temperature for the residual compressive strength of fiber-reinforced SCC. Regarding the flexural tensile strength, the temperature of 200 °C was found to be a changing point of the SCC after heating to elevated temperatures. A sharp decrease in the compressive strength is observed when the target temperature exceeds 400 °C. For temperatures below 400 °C, the compressive strength is enhanced slightly with the increase of the target temperature. Moreover, incorporating a fiber cocktail is an effective way to improve the explosive spalling resistance and residual mechanical properties in the case of fire. Finally, the regression analysis was performed and the proposed correlations between the residual strengths and elevated temperatures are compared with equations in the literature. Good accuracy of the proposed correlation is achieved for fiber-reinforced SCC.

Mechanical Properties of Self-compacting Concrete Mixed with Composite Fibers

Mechanical Properties of Self-compacting Concrete Mixed with Composite Fibers

Grey model study on strength and pore structure of self-compacting concrete with different aggregates based on NMR

To promote the application of machine-made sand and shale ceramsite in self-compacting concrete (SCC), this paper takes four kinds of SCC with different aggregates as the research object. The working performance and mechanical properties of four kinds of SCC are tested when gravel and shale ceramsite are used as coarse aggregate and machine-made sand and river sand are used as fine aggregates. The T2 spectrum of self-compacting concrete with different aggregates at different ages is obtained by NMR technology, and the pore size distribution curve is obtained. Then, the grey relation entropy theory is used to analyze the influence of pore structure on the mechanical properties of SCC. Finally, based on the pore structure parameters, a GM (1,3) prediction model for the compressive strength of SCC is established. The results show that: shale ceramsite and machine-made sand can be used as substitutes for gravel and river sand; The working performance of shale ceramsite SCC and river sand SCC is better than that of gravel SCC and machine-made sand SCC; The mechanical properties of gravel SCC and machine-made sand SCC are better than shale ceramsite SCC and river sand SCC, respectively. Small pores and porosity less than 0.02 μm have little effect on the mechanical properties of SCC, while spectral area and larger pores have a greater impact on it; GM（1,3）model can achieve a more accurate prediction of the mechanical properties of shale ceramsite concrete, and the prediction error of gravel concrete is relatively large, reflecting that compared with shale ceramsite, gravel has a great influence on the mechanical properties of concrete.

Synthesis and characterization of ladle furnace slag on the mechanical properties of self-compacting concrete

The current study examines the use of industrial wastes in the construction industry. Slag from ladle furnaces (Ld) is a solid waste product of the steel industry. Primary and secondary steel-making processes are used in the production of steel from iron or scrap. Ladle furnace slags are steel slags created during the secondary steel-making process. In this study, conventional and self-compacting M25 grade concrete mixtures were made with Ld slag in place of some of the cement. It is also utilised as a filler ingredient in self-compacting concrete (SCC), where the content of Ld slag is 99 kg/m3. In concrete mixtures, Ld slag was used to substitute cement to varying degrees (0 %, 5 %, 10 %, 15 %, 20 %, 25 %, and 30 %). Self-compacting concrete (SCC) was tested for workability in its fresh form as well as for filling, passing, and viscosity. The hardened state of these mixes was also studied, and compressive and split tensile strengths were determined. This slag had its cementitious qualities improved by activating it mechanically for application in concrete mixing. The results show that substitution of up to 10 % of the Ld slag can increase concrete strength, but it also provides good strength that is on par with that of regular concrete. However, when SCC was generated, it provided the best strength of all. SCC can be formed by replacing up to 15 % of the cement with Ld slag and still get the desired results.