Self-compacting Concrete Mixtures Research Articles

Development of Self-Compacting Concrete Incorporating Rice Husk Ash with Waste Galvanized Copper Wire Fiber

This research work is devoted to the experimental investigation of both rheological and mechanical properties of self-compacting concrete (SCC) produced with waste galvanized copper wire fiber and rice husk ash (RHA). In the study, three different volume fractions of 0.5 p to 0.75 percent, 1 percent of scrap copper wire fiber as reinforcing material, and 2 percent RHA as cement replacement were used. To evaluate the fresh characteristics of SCC, the slump flow, J-ring, and V-funnel experiments were conducted for this investigation. Compressive strength, splitting tensile strength, and flexural strength of the concrete were conducted to assess the hardened properties. The test was carried out to compare each characteristic of plain SCC with this modified SCC mixture, containing RHA as pozzolanic materials and copper fiber as reinforcing material. Incorporating copper fiber in the SCC leads to a drop in fresh properties compared to plain SCC but remains within an acceptable range. On the other hand, the inclusion of 2% RHA makes the SCC more viscous. Although adding 2% RHA and 1% copper wire in SCC provide the highest strength, this mix has an unacceptable passing ability. The SCC mix prepared with 2% RHA and 0.75% copper fiber is suggested to be optimum in terms of the overall performance. According to this study, adding metallic fiber reinforcement like copper wire and mineral admixture like RHA can improve the mechanical properties of SCC up to a certain level.

Prediction of the rheological properties of nanosilica blended self-compacting concrete under the influence of a dispersing agent

The effect of nanosilica under the influence of dispersing agents on the fresh empirical and fundamental rheological properties of self-compacting concrete (SCC) is a complex phenomenon which has been investigated in this paper. Models to predict the rheological properties of nanosilica blended SCC are also lacking to avoiding/saving comprehensive and costly rheology laboratory trials mainly when these tests are unavailable or limited. To these ends, 315 laboratory tests were performed on 15 blended SCC mixtures, manufactured using five nanosilica dosages, 0%, 0.5%, 1%, 1.5%, 2%, and three dispersing superplasticizer dosages, 0.62%, 0.66%, 0.70%, by weight of cement. Fundamental rheological properties of the SCC mixes were assessed by using a rotational concrete rheometer based on the nonlinear modified Binghamian model. Results showed that SCC mixes are sensitive to nanosilica and superplasticizer admixtures producing a complex non-linear effect on their empirical and rheological properties. Based on these trends, eleven empirical models were proposed to predict the fresh empirical and rheological properties of the SCC mixes. A statistical analysis demonstrated the good fitting of the proposed models with the measured properties of SCC mixes during the laboratory trials. These models could serve for design and production of nanosilica blended SCC as alternative approach.

Evaluation of use of marble and granite cutting waste to the production of self-compacting concrete

Due to the continuous storage of large quantities of marble and granite waste (MGW), generated during the processing of ornamental stones, researchers have been using this material in a sustainable way to reduce its adverse impacts on the ecosystem. In this study, the main objective was to evaluate the effect of using MGW on mechanical properties and durability of self-compacting concretes (SCC), as part of the fines required to ensure self-compacting characteristics. Also, it was investigated this material as a new possibility in the composition of a ternary cement modality. For this, an experimental program was developed with four SCC mixtures, in which tests were performed to determine the properties in the fresh state, hardened properties, durability, and microstructural analyses. The test results indicated that all mixtures complied the self-compacting requirements and the incorporation of MGW contributed to the stabilization of the concretes. The mixture with CPV-ARI cement and MGW incorporated as fine in the concrete, and the mixture with MGW both incorporated as fines in the concrete and in the composition of ternary cement CP-MMG did not present statistically significant differences for some results of the mechanical properties. Besides, these mixtures provided improvements and similar results of some durability and microstructural tests, respectively. In general, the different possibilities of utilization of the residue proposed in this study, generate an appropriate destination for MGW and propose a viable alternative for the reduction of clinker consumption in cement production.

Optimization of Self-Compacting Concrete Containing Blast-Furnace Slag Compositions

The paper deals with composition design of self-compacting concrete containing blast furnace granulated slag and polycarboxylate type superplasticizer in a wide range of concrete strength classes. Optimal superplasticizer content, cement, and blast furnace slag consumptions are obtained from the viewpoint of minimum water demand and water-cement ratio, maximum self-compacting concrete mixture workability retention, and concrete strength. A significant effect of joint influence of superplasticizer and blast furnace slag is demonstrated. The possibility of minimizing the cement consumption at optimal superplasticizer content and slag consumption of 100–120 kg/m3 is shown. Dependences for calculating SCC strength at 1, 7, and 28 days vs. the water-cement ratio are obtained. It is found that the nature of correlation dependences for SCC splitting and compression strengths when using the blast furnace slag and the superplasticizer is linear. Optimization of SCC compositions using mathematical programming enables to obtain compositions with a lowest possible cost while providing a set of specified parameters.

Investigating the Behavior of Waste Alumina Powder and Nylon Fibers for Eco-Friendly Production of Self-Compacting Concrete.

Self-compacting concrete (SCC) incorporating secondary raw materials has been extensively used around the globe due to its improved fresh, mechanical and durability properties. This study was planned to evaluate the suitability of locally available waste alumina powder (AP) and nylon textile fibers (NF) as a partial replacement for fine and coarse aggregates with the ultimate goal to locally produce SCC with desired properties. The used AP was acquired from a local market and NF was collected from a local textile factory. Various dosages of AP (10%, 20%, 30%, 40% and 50% by volume of fine aggregates) and NF (1% and 2% by volume of coarse aggregates) were studied. Tests including slump flow, V-funnel and J-ring tests were performed for examining the fresh properties of developed SCC. Results showed that the addition of AP has an insignificant effect on the superplasticizer dosage for maintaining a constant flow of 70 cm. However, a higher dosage of superplasticizer was required for a mixture with increasing dosages of NF to sustain a constant flow. Similarly, slump flow time (for a spread of 50 cm) and V-funnel time increased for mixtures with higher dosages of AP and NF. Tested SCC mixtures incorporating 40% and 50% of AP with 1% and 2% of NF showed an extreme blocking assessment due to their increased interparticle friction, the higher water absorption capacity of used AP and NF leading to increased flow resistance and hence, showed lower passing ability. The compressive strength was 16% higher for specimens incorporating 40% of AP due to the filling effect of AP which fills the micro-pores, leading to a more dense and compact internal micro-structure, confirmed through scanning electron microscopy analysis. An ultrasonic pulse velocity test conducted on hardened specimens verified the findings of the compressive strength results. Moreover, it was observed that NF has an insignificant effect on the compressive strength; however, flexural strength was increased due to the incorporation of NF, especially at higher dosages of AP.

Effects of rubber aggregates on the physical-mechanical, thermal and durability properties of self-compacting sand concrete

The aim of this research was to study the effect of incorporating waste rubber aggregates on the physical, mechanical, thermal and durability performance of Self-Compacting Sand Concrete SCSC mixtures. For this purpose, the separately developed Rubberized Self-Compacting Sand Concrete RSCSC were prepared with three fractions of rubber grains where the natural aggregates were replaced with powder rubber, sand rubber and gravel rubber and four addition ratios (5, 10, 15 and 20%) as volume rates. The performed fresh properties using slump-flow, spreading, t500, sieve stability and air-entrained content tests proved better results for the RSCSC in comparison with reference concretes. Hardened state characterization of the concretes exhibited decreases in the mechanical properties of the RSCSC but the thermal conductivity and the dynamic elastic modulus were improved. Assessment of the concrete’s durability was accomplished through determination of apparent porosity, capillary absorption. Therefore, RSCSC to be can used in structural elements of dense reinforcement and complex formwork. Furthermore, this allows promising solution to reduce the impact of waste tyres on the environment and fight pollution.

Rheological and hardened properties of self-compacting concrete using hollow glass microspheres as a partial replacement of cement

The main purpose of this research was focused mainly on the rheological influence of the “ball bearings” behavior of hollow glass microspheres (HGM), which affect the workability and stability of cementitious materials. They were used as partial replacement of cement on self-compacting concrete (SCC), in rates of 0% and 5%, promoting a possible reduction in the chemical admixtures consumption. The rheological properties were determined experimentally by direct tests using a rotational concrete rheometer and indirectly by empirical tests such as the slump flow, J-ring and L-box. From the data collected experimentally in direct tests, the behavior of mixtures was deeply analyzed by comparing the Bingham and the modified Bingham model, considering the influence of the plug flow. For this analysis, algorithms based mainly on the Reiner-Riwlin equations were developed with the purpose of showing in a simpler and more schematic way the iterative models applied in each case, contributing to the advancement of rheology of cement-based materials. In addition to rheological tests carried out, concrete properties in the hardened state were also measured at 28 days of curing. Young's modulus, Poisson's ratio, compressive strength, tensile strength, bending strength and chloride migration coefficient in a non-steady state were measured. The experimental results indicate that HGM incorporation improved the properties in the fresh state and slightly reduced the hardened properties of the SCC mixtures.

Utilization of Waste Sole Leather with Fly Ash for Self-Compacting Concrete

The majority of solid waste from leather industries comes from various processes after manufacturing leather products, and it has been gathered separately from industries. Sole leathers were also emitted in the leather industry. After used, sole leather is thrown at dump yard and the dumping of sole leather on the ground is highly damaging to the environment’s health, and the recycling procedure is approximately expensive, therefore this research examines the creation of Self-Compacting Concrete (SCC) mix using Fly Ash and Sole Leathers. This article examines that utilization of waste sole leather including F.A. (Fly Ash) and superplasticizer (S.P.) in self-compacting concrete (SCC) mixtures. fly Ash & sole leather is a novel research concept with high deformability and moderate viscosity, which is required to provide consistent solid particle dispersion during shipping, installation, and until the concrete sets. As per obtained the findings of the current research, the addition with sole leather and fly ash in conjunction with a superplasticizer appears to improve the fresh, hardened characteristics developed strength & proper durability qualities in SCC. The maximum compressive strength was obtained for SCC5%F.A.+5%S.L. i.e., 41.10 MPa as compare to other mix proportions i.e. SCC10%F.A.+7.5%S.L. (39.95 MPa) & SCC15%F.A.+10%S.L. (36.70 MPa).

Properties of sustainable self-compacting concrete containing activated jute fiber and waste mineral powders

Self-compacting concrete (SCC) mixtures requires a large amount of Portland cement and thus resulting in high CO2 emissions, expanding its application has been in question to environment sustainability. Accordingly, environmental-friendly alternatives to Portland cement in SCC mixtures are deemed necessary for the progress of SCC in construction. In this investigation, treated jute fibers and mineral powders were used to replace cement in SCC mixtures. The effects of fibers and powder contents, fiber treatment, and mineral powder types on the workability and mechanical properties of SCC mixtures were investigated through slump-flow, compressive, and flexural tests. A microstructure was conducted through scanning electron microscopy. It was concluded that mineral powders and jute fibers could significantly improve the workability and mechanical properties of SCC. The microstructure observations demonstrated that the proposed methods are capable of enhancing the mechanical properties of SCC with an optimum fiber content. Specifically, a combination of 0.1% jute fibers and 75 μm zeolite powders were found to achieve the best mechanical properties. The relevant results supply fundamental reference and background for artificial intelligence and multi-function development for future infrastructure.

Self-compacting concrete with recycled concrete aggregate subjected to alternating-sign temperature variations: Thermal strain and damage

Any variation in temperature alters the dimensions of a concrete structure and provokes thermal stress. Moreover, the propagation of micro-cracking decreases the strength of concrete that is exposed to sub-zero temperatures (freezing), to heat phenomena (heating), or to cyclical thermal variations, especially when prepared using Recycled Concrete Aggregate (RCA). A reference self-compacting concrete (SCC) mix made with 100% coarse and fine natural aggregate and three SCC mixes containing 100% coarse and/or fine RCA in replacement of natural aggregate were tested in this study of the thermal performance of SCC and the related effects of RCA. The mixtures were subjected to five thermal tests designed with positive and negative, and both constant and cyclical, extreme-ambient temperature variations, reaching temperatures of − 15 °C and 70 °C. Stiffness, weight, compressive strength, thermal deformability, and internal damage of the SCC mixtures were monitored throughout suitable testing. Internal damage, hygroscopicity, and loss of strength increased at temperatures below 0 °C, especially in the mixtures containing 100% coarse RCA, although the SCC manufactured with simultaneous additions of fine and coarse RCA fractions showed the worst performance. Overall, RCA performed better under positive temperature variations. The test results lead to the recommendation of a linear thermal expansion coefficient of 1.2·10−5 °C−1 in calculations for SCC containing RCA under those extreme environmental conditions.

Effect of granite industry waste addition on durability properties of fly ash blended self-compacting concrete

The continuous production of granite powder (GP) waste causes a deadly impact on environment and human life. This present study thus examines the impact of granite powder (GP) as substitute to natural fine aggregate (up to 60%) on compressive strength and durability properties of eco-friendly fly ash blended self-compacting concrete (SCC). Results revealed that strength enhanced on incorporation of up to 40% GP in concrete mixture than fly ash blended control mixture. Resistance against chloride, carbonation and corrosion improved for incorporation of up to 50% GP in concrete mixture than fly ash blended control mixture. Moreover, all the blended SCC mixtures, except SCC mixture containing 50% and 60% GP, showed higher compressive strength than ordinary Portland cement (OPC) based control SCC mixture at higher days of curing. Besides, all the blended SCC mixtures, except mixture containing 60% GP, showed better resistance against chloride, carbonation, drying shrinkage and corrosion than OPC based control SCC mixture. It was hence concluded that GP up to 50% as an alternative of fine aggregate could be positively incorporated in the production of eco-friendly fly ash blended SCC for the improvement of aforesaid durability properties (with little higher precaution against drying shrinkage).

The effect of elevated temperature on the properties of SCC’s produced with different types of fibers

Self-compacting concrete (SCC) has various advantages such as improved workability and physical properties with advanced compressive strength against traditional structural concretes. However, under high temperatures, the dense composite structure with a compact matrix can facilitate the deterioration of concrete. This study aims to determine the effect of polypropylene, steel, and glass fibers on the mechanical and physical properties of SCC at elevated temperatures. In the fibrous mixtures, polypropylene fiber was used as 0.1%, 0.3%, and 0.5%, steel fiber was used as 0.1%, 0.2%, and 0.3%, and glass fiber was used as 0.1%, 0.3%, and 0.5% by volume of concrete. In addition, a fiber-free SCC control mix was produced to determine the variation of the properties of SCC mixtures. For this purpose, ten SCC mixtures were designed to estimate the workability and hardened properties of the SCC mixtures. The effect of high temperature was investigated by performing ultrasonic pulse velocity, compressive strength, splitting tensile strength, and apparent porosity tests on hardened SCC mixtures that were exposed to 200, 400, and 600 °C. The microstructure of these specimens is observed by using Scanning Electron Microscopy (SEM) on the cross-sections obtained from the hardened SCC mixtures. As a result of the study, it was observed that the use of steel or glass fiber (up to 0.5% by volume) improved the mechanical properties of SCC up to 600 °C. However, these improvements were not seen when using polypropylene fiber in the same fiber volumes.

Experimental and numerical investigations of interfacial bond in self-compacting concrete-filled steel tubes made with waste steel slag aggregates

New self-compacting concrete (SCC) mixtures were designed to improve the interfacial bond strength in concrete-filled steel tubes (CFST) at 30 days and one year. The proposed SCC mixtures involved the strengthening of bond strength by using waste steel slag aggregates (SSA). A total of thirty-six circular and squared tube specimens with different ratios (0%, 25% and 50%) of SSA as a replacement by weight of coarse and fine aggregates in SCC were initially prepared. The results revealed that the using of SSA in SCC enhanced the specimens' bond strength for both shapes of steel tubes and the bond strength was reduced with an increase of concrete's age. Additionally, the incorporating of SSA did not decrease the loss in bond strength at one year. A three-dimensional non-linear finite element (FE) analysis was further conducted to simulate the interfacial bond-slip mechanism between two surfaces of the infill concrete and inner steel tubes.

Development of an artificial neural network model to predict waste marble powder demand in eco‐efficient self‐compacting concrete

AbstractThe marble industry produces large amount of waste at almost every stage of marble processing. This waste is always uncontrollably discharged into open areas. Therefore, the consumption of Waste Marble Powder (WMP) in concrete is very important and will provide both an economic gain for concrete industries and an opportunity to achieve eco‐efficient concrete production. Self‐Compacting Concrete (SCC) is mostly preferred concrete type which uses the WMP as powdered material. Thus, to increase WMP usage in the production of eco‐efficient SCC, it is aimed in this study to develop a model that can predict WMP demand. To develop this model, Artificial Neural Network (ANN), an artificial intelligence method, was preferred. An ANN model was developed using a comprehensive dataset that included eco‐efficient SCC mixture compositions, workability measurements, and compressive strengths. The ANN model with seven inputs and one output as WMP was successfully trained and managed to produce the correct outputs to both validation and test datasets. Mix design of SCC with aimed properties can be a long process compared to conventional concrete. The proposed ANN model could reduce time loss in the production process. ANN's success is expected to facilitate the production of eco‐efficient SCC with WMP.

Development of High-Tech Self-Compacting Concrete Mixtures Based on Nano-Modifiers of Various Types.

Promising areas of concrete material science are maximum greening, reducing the carbon footprint, and, at the same time, solving the problems of increasing the cost of raw materials using industrial waste as modifiers for self-compacting concrete mixtures. This study aimed to review, investigate and test from the point of view of theory and practice the possibility of using various industrial types as a nano-modifier in self-compacting concrete with improved performance. The possibility of nano-modification of self-compacting concrete with a complex modifier based on industrial waste has been proved and substantiated theoretically and experimentally. The possibility of improving the technological properties of concrete mixtures using such nanomodifiers was confirmed. The recipe and technological parameters of the process were revealed and their influence on the characteristics of concrete mixes and concretes were expressed and determined. Experimental technological and mathematical dependencies between the characteristics of the technological process and raw materials and the characteristics of concrete mixtures and concretes were determined. The optimization of these parameters was carried out, a theoretical substantiation of the obtained results was proposed, and a quantitative picture was presented, expressed in the increment of the properties of self-compacting concrete mixtures using nano-modifiers from industrial waste concretes based on them. The mobility of the concrete mixture increased by 12%, and the fluidity of the mixture increased by 83%. In relation to the control composition, the concrete strength increased by 19%, and the water resistance of concrete increased by 22%. The ultimate strains decreased by 14%, and elastic modulus increased by 11%.

The Mechanical Behavior of Self-Compacting Concrete SCC Samples Locally Produce

The main objectives of this research were to obtain a locally self-compacting concrete SCC, a modern concrete with a high property, that enables it to pass and flow through the structural elements and within the steel bars under its own weight only. which was produced and tested in the reinforced concrete laboratory, using local materials in its composition. The mixtures showed no separation or accumulation of the concrete mixture, which enables us to use it in the construction, restoration and structural strengthen at the lowest costs of production. Three concrete mixtures have been produced using three grades of cement (550, 500 and 450-475 kg/m3), using three types of chemical plasticizers, which has been coded as (3500, NN, and S) and two plasticizers ratios (2%, and 2.5%) of the cement weight, verified by the experiments of the fresh properties of the concrete mixture, determination of the cylindrical strength at the age of 28 days, and the measurement of the stress-strain(ϭ, ξ) for the tested samples. It was found that the self-compacting concrete mixture with cement grade (550kg/m3) using the chemical plasticizer (3500) at (2%) ratio of cement weight, gave the best properties at a water/cement (W/C) ratio of (0.39), with relatively high concrete strength.

Effects of Cement Additions on Self-compacting Concrete Durability Indicators

This study highlights the effect of initial curing time on sustainability indicators such as sorptivity (S), water absorption (WA) and total porosity (P) of self- compacting concretes (SCC) containing the blended cement such as limestone cement (CEMIIA-L42.5) and pozzolanic cement (CEMII-A-P42.5). The durability test (acid and sulfate attack) of SCCs is also studied in this researcher. For this purpose, three water/binder (W/B) ratios were used, Six SCC mixtures were prepared and tested in the fresh state (slump follow, flow time, J-Ring, L-Box, V-Funnel and sieve segregation), the main properties in the hardened state compressive strength (Sc), S, WA and P of the SCC mixtures were studied and evaluated each in its different curing. Furthermore, the results of the Sc and transfer properties are globally significantly affected by the hot climate during the design and maturation phase. On the other hand, the values of S to SCC for pozzolanic cement are lower compared to limestone cement and this regardless of W/B ratio and the cure mode. The difference between the mixtures SCC-L32, SCC-L38 and SCC-L44 at the 28 day is between 2.45%, 87.57% depending on the cure mode and the W/B ratio. In addition, WA was observed to range from 5.8 to 7.1%. On the other hand, a good correlation was found between sustainability indicators and Sc. Durability has also been improved for pozzolanic cement compared to that of limestone cement as compressive strength against sulfate and acid attack have been improved.

Prediction and sensitivity analysis of self compacting concrete slump flow by random forest algorithm

Self-compacting concrete (SCC) is a construction material with many advantages, including high performance and the capacity to self-compact without mechanical vibration. As a result, SCC is widely used in construction, especially at locations where concrete structures are difficult to construct. Filling ability is one of the three basic requirements that must be met when designing the SCC mix. The slump flow (SF) is used to determine the SCC mixture's filling capacity. As a result, it is critical to estimate this number fast and precisely. The purpose of this study is to propose the use of a random forest (RF) model to predict the SF of SCC and to assess the effect of input parameters on output parameters. The study constructed the RF model using a dataset of 507 experimental results collected, which is the biggest data collection compared to previous studies on this subject. Additionally, a 10-fold cross-validation approach is used to improve the model's prediction performance. As a result, the performance assessment criteria for the testing dataset have values of RMSE = 59.5664 mm, MAE = 32.4483 mm, and R = 0.8614, respectively. This result shows that the RF model is an effective tool in predicting the SF of SCC.

Prediction and sensitivity analysis of self compacting concrete slump flow by random forest algorithm

Self-compacting concrete (SCC) is a construction material with many advantages, including high performance and the capacity to self-compact without mechanical vibration. As a result, SCC is widely used in construction, especially at locations where concrete structures are difficult to construct. Filling ability is one of the three basic requirements that must be met when designing the SCC mix. The slump flow (SF) is used to determine the SCC mixture's filling capacity. As a result, it is critical to estimate this number fast and precisely. The purpose of this study is to propose the use of a random forest (RF) model to predict the SF of SCC and to assess the effect of input parameters on output parameters. The study constructed the RF model using a dataset of 507 experimental results collected, which is the biggest data collection compared to previous studies on this subject. Additionally, a 10-fold cross-validation approach is used to improve the model's prediction performance. As a result, the performance assessment criteria for the testing dataset have values of RMSE = 59.5664 mm, MAE = 32.4483 mm, and R = 0.8614, respectively. This result shows that the RF model is an effective tool in predicting the SF of SCC.

Prediction and sensitivity analysis of self compacting concrete slump flow by random forest algorithm

Self-compacting concrete (SCC) is a construction material with many advantages, including high performance and the capacity to self-compact without mechanical vibration. As a result, SCC is widely used in construction, especially at locations where concrete structures are difficult to construct. Filling ability is one of the three basic requirements that must be met when designing the SCC mix. The slump flow (SF) is used to determine the SCC mixture's filling capacity. As a result, it is critical to estimate this number fast and precisely. The purpose of this study is to propose the use of a random forest (RF) model to predict the SF of SCC and to assess the effect of input parameters on output parameters. The study constructed the RF model using a dataset of 507 experimental results collected, which is the biggest data collection compared to previous studies on this subject. Additionally, a 10-fold cross-validation approach is used to improve the model's prediction performance. As a result, the performance assessment criteria for the testing dataset have values of RMSE = 59.5664 mm, MAE = 32.4483 mm, and R = 0.8614, respectively. This result shows that the RF model is an effective tool in predicting the SF of SCC.