Compressive Strength Of Self-compacting Concrete Research Articles

Modelling of compressive strength of self-compacting concrete containing fly ash by gene expression programming

In the modelling study, two models are presented by gene expression programming (GEP) for estimation of compressive strength (fc) of self-compacting concrete (SCC) with fly ash (FA). The main difference between two models is the number of heads determined in the development of models. These established models are proposed to predict the fc values by utilizing amount of cement, water, FA, coarse and fine aggregate, and superplasticiser, and age of specimen as input values for SCC mixtures. In establishment of the proposed models, 516 compressive strength values are utilized; these values were obtained from 34 published scientific experimental literatures on SCC with FA. The training and testing sets employed in the creation of models consist of 368 fc results of SCC mixtures. The models are confirmed with remaining 148 fc results of SCC mixtures, which are not employed in training and testing sets. The estimated fc results attained from established models were compared with fc results of experimental studies, and previously proposed artificial neural network (ANN) model. These comparisons and results of statistical evaluation have strongly revealed that results of established models match well with the experimental results, and they are considered very reliable

FRESH AND MECHANICAL CHARACTERISTICS OF SELF-COMPACTING POLYPROPYLENE FIBER CONCRETE INCORPORATED WITH KAOLIN

Self Compacting Concrete (SCC) is concrete with high fluidity so that it can flow and fill the spaces in the mold without the compaction process. This study discusses the effect of the adding of kaolin and polypropylene fibers in order to increase the flowability, compressive strength, flexural strength, and tensile strength in self-compacting concrete. The additional material of kaolin was 5%, 10%, and 15% of the cement weight. The polypropylene fibers were 1%, 1.5%, and 2%. The flowability test, which was used, was Table flow, V-Funnel, and L-Box. Compressive strength testing was conducted when the concrete was 7, 14, and 28 days old. The flexural test was performed with a measurement of 150 x 150 x 600 mm as many as 18 specimens tested at the age of 28 days. The results showed that the addition of kaolin and polypropylene fibers met the flowability specifications of self-compacting concrete. The addition of polypropylene can increase the flexural strength and tensile strength of the concrete beam, but cannot increase the compressive strength of self-compacting concrete.

Fresh properties and compressive strength of self compacting concrete with fines aggregate replacement using red brick powder and rice husk ash

PurposeThis study aims to discuss the results of fresh properties and compressive strength of self-compacting concrete using ingredients added red brick powder as a fine aggregate substitute. The results of the study were compared with the properties of fresh properties and compressive strength with ingredients added by rice husk ash, which is also a fine aggregate substitute. In addition, the initial compressive strength of each of these variations was also examined to accelerate the completion time of construction projects using self-compacting concrete.Design/methodology/approachThis research was conducted in a laboratory by testing the characteristics of fresh and hardened properties of self-compacting concrete.FindingsFresh properties testing is carried out in the form of V-funnel, flow table, J-ring and L-box where all specimens produce quite varied flow rates. Compressive strength was estimated at ages 3, 7, 14 and 28 days with cylindrical specimens with a diameter of 150 mm and a height of 300 mm. The variation of fine aggregate substitutes used is 20, 40 and 60 per cent.Originality/valueFrom the results of the compressive strength, it can be concluded that the added material is categorized as self-compacting concrete with high initial compressive strength, while at 28 days, the compressive strength test results are categorized as high-strength self-compacting concrete.

Comparative of the Use of Carbon and Steel Fiber to the Mechanical Properties of Self Compacting Concrete

This research is a comparative study, the use of carbon fiber and steel fiber for Self-Compacting Concrete (SCC). In previous studies, it was proven that the addition of steel fibers can increase the compressive and tensile strength of SCC. While carbon fiber is one of the most widely used materials for structural reinforcement in recent years. Therefore it is necessary to do a comparative study of the use of carbon fiber if applied to SCC. The percentage increase in carbon fiber and steel is 0.5%, 1%, and 1.5%. Then do the testing of: slump test, compressive strength, tensile strength and flexural strength. The results showed the optimal percentage of steel fiber addition of 1.5%, can increase the compressive strength of SCC by 11%. However carbon fiber and steel do not increase the tensile strength of SCC, and tend to reduce flexural strength. Other results show that carbon fiber is not suitable for use in SCC.

Effects of sandstone slurry, the dosage of superplasticizer and water/binder ratio on the fresh properties and compressive strength of self-compacting concrete

Abstract This paper comprises the results and discussion of an experimental investigation carried out to study the effect of sandstone slurry, the dosage of superplasticiser and water/binder ratio on the fresh properties and compressive strength of self-compacting concrete (SCC). Three water binder ratio 0.36, 0.34 and 0.32 were selected. For each water/binder ratio three superplasticiser dosage has been fixed. Sandstone slurry has replaced with cement at 0% and 35%. To study the effect on fresh property with different w/b ratio and SP dosage, slump flow test, T500, V-funnel, Sieve segregation and L-Box test and compressive strength test was conducted at 7,14, 28 days and results are reported. The result showed that up to 1.7% dosage of Superplasticizer increases the strength of concrete. Excess of SP dosage, compressive strength decreased. Fresh property criteria were also not in line. The inclusion of sandstone slurry by substitution to cement was found to be very beneficial to fresh self-compacting concrete. Results from the above studies were indicated that, the range of superplasticiser dosage might be fixed from 1.35% to 1.7% by weight of binder along with 0.34 water/binder ratio provides optimum strength with the acceptable range of fresh properties of SCC. Although, compressive strength decreased with 35% replacement of sandstone slurry content, for lower percentages of replacement of cement with sandstone slurry may perform better and continuing it in future work.

Effect of fine fillers from industrial waste and various chemical additives on the placeability of self-compacting concrete

The premise for the study reflected in this article is the need to dispose of industrial waste, which is increasingly being used in the construction materials industry. Also, dynamically developing building industry demands attention of scientists and a direction of their works on improvement of the technology of carrying out construction works. Thus, the article is devoted to studying the influence of various chemical additives and fine fillers (industrial wastes) available in Kazakhstan on selfcompacting concrete (SCC) mixtures and its rheological, physical, and technical properties. According to the studies, revealed the most efficient type of fine-dispersed filler and the most optimal type of chemical additive to enable obtaining a high-quality SCC mixture based on local raw materials. As a result, the use of microsilica in comparison with other industrial wastes resulted in a conglomerate with high compressive strength of SCC at early terms of curing. In terms of economic efficiency and quality improvement, the results of study are of practical value for the manufacturers of ready-mixed concrete operating in Kazakhstan.

Tunnel fire resistance of self-compacting concrete coated with SiO2 aerogel cement paste under 2.5 h HC fire loading

Self-compacting concrete (SCC) widely used in tunnel structure is prone to spalling when it is subjected to the fire disaster. The fire-resistant materials coated on the surface of concrete are considered as an effective way to prevent concrete from being destroyed in a fire accident. However, current these coatings are difficult to withstand a high temperature, for example, tunnel fire temperature, and a longer-term fire. In this paper, a 40 mm thickness of SiO2 aerogel cement paste (ACP) coating was prepared to investigate the protective effect for SCC in a simulated tunnel fire with the maximum temperature of 1100 °C for 2.5 h. The mechanical properties, thermal conductivity and fire resistance of SiO2 ACP, and the compressive strength of SCC with or without ACP coating in the simulated tunnel fire were tested. The results showed that ACP exhibited excellent mechanical and durable performances and low thermal conductivity. The 40 mm thickness of ACP has a strong thermal insulation capacity and can effectively withstand tunnel fire up to 2.5 h. The SCC samples under the protection of ACP did not undergo compressive strength degradation and destruction of microstructure. The interfacial temperature of ACP and SCC was much lower than the critical value (380 °C) in a 2.5 h tunnel fire. Therefore, ACP can provide a good choice for protection of SCC in a tunnel fire with a high temperature and long time.

Mix-design and properties of self-compacting concrete made with calcareous tuff

This paper focuses on the possibility of using calcareous tuff (CT) in self-compacting concrete (SCC) production. In concrete mixtures, CT is used as sand and its fines as partial cement replacement. Mixtures are prepared with three different sand/mortar ratios (S/M) of 0.40, 0.45 and 0.50 with a varying superplasticiser content (SP). Cement was substituted by fines of calcareous tuff (CTF) with percentages of 0, 5, 10, 15, 20, 25 and 30% for S/M ratios of 0.40 and 0.45 with a varying SP dosage up to the superplasticiser saturation dosage (SSD). The filling, passing ability and segregation resistance tests are used to assess the fresh properties of SCC. The compressive strength of SCC was also determined at 3, 7, 28 and 56 days. The results show that the use of CT improves the flowability and stability of both SCM and SCC. SCC mixtures made with CT satisfy the specifications and guidelines for SCC production. The maximum strength obtained at 28 days was with mixtures SCC incorporating 10% of CTF, which revealed clearly the good adhesion between CT and cement matrix. Finally, CT constitutes a good local eco-material, abundantly available, for the SCC design.

Rheological properties, compressive strength and life cycle assessment of self-compacting concrete containing natural pumice pozzolan

Abstract In this study, the life cycle assessment (LCA), rheological properties and compressive strength of self-compacting concrete (SCC) mixtures containing natural pumice pozzolan (NPP) were evaluated. The rheological properties of SCC including filling ability, passing ability and stability against segregation were determined using slump flow, V-Funnel, L-Box, J-Ring and sieve segregation tests. The compressive strength was measured at the age of 28 and 91 days. Using the LCA tool, the life cycle of the SCC mixtures presented in this study was evaluated and global warming potential (GWP) plus air pollutant parameters (APP) including lead, VOC, CO, NOX, PM10 And SO2 were measured. The results showed that the range of calculated compressive strength is between 26 and 55 MPa, and the Euro code requirements are met for almost all mixtures on rheological properties. Also, in SCC mixtures containing 10, 20 and 30% NPP, GWP production decreased by 9.3%, 18.6% and 27.8%, and the rate of emission of AAP was decreased from 3.6 to 29.9%, respectively.

Rheological Behavior and Microstructure Characteristics of SCC Incorporating Metakaolin and Silica Fume.

This study explores the effects of metakaolin (MK) and silica fume (SF) on rheological behaviors and microstructure of self-compacting concrete (SCC). The rheology, slump flow, V-funnel, segregation degree (SA), and compressive strength of SCC are investigated. Microstructure characteristics, including hydration product and pore structure, are also studied. The results show that adding MK and SF instead of 4%, 6% and 8% fly ash (FA) reduces flowability of SCC; this is due to the fact that the specific surface area of MK and SF is larger than FA, and the total water demand increases as a result. However, the flowability increases when replacement ratio is 2%, as the small MK and SF particles will fill in the interstitial space of mixture and more free water is released. The fluidity, slump flow, and SA decrease linearly with the increase of yield stress. The total amount of SF and MK should be no more than 6% to meet the requirement of self-compacting. Adding MK or SF to SCC results in more hydration products, less Ca(OH)2 and refinement of pore structure, leading to obvious strength and durability improvements. When the total dosage of MK and SF admixture is 6%, these beneficial effects on workability, mechanical performance, and microstructure are more significant when SF and MK are applied together.

Effect of High-Volume Ceramic Waste Powder as Partial Cement Replacement on Fresh and Compressive Strength of Self-Compacting Concrete

AbstractNumerous regulations have been imposed worldwide by governments and environmental organizations in order to reduce the negative environmental impact resulting from large numbers of solid wa...

Water Absorption and Compressive Strength of Self-Compacting Concrete Incorporating Fly Ash and Quarry Dust

Water Absorption and Compressive Strength of Self-Compacting Concrete Incorporating Fly Ash and Quarry Dust

RETRACTED ARTICLE: Prediction model for optimized self-compacting concrete with fly ash using response surface method based on fuzzy classification

This paper elucidates a data predicting model using an intelligent rule-based enhanced multiclass support vector machine and fuzzy rules (IREMSVM-FR) while optimizing the test practices and trials needed for the proportioning of self-compacting concrete (SCC) using response surface methodology (RSM). The SCC requires a wide range of material content, and hence, more numbers of investigations were typically essential to select a suitable mixture to get the required properties of SCC. Taguchi’s methodology with an L18 array and three-level factor was used to reduce the number of the experiment. Four regulating elements, i.e., cement, fly ash, water powder ratio and superplasticizer, were used. Two results such as slump flow in the fresh state and the compressive strength in the hardened state at 28 days were assessed. Optimizations of the results were set by using RSM. The reactions of material parameters examined to optimize the fresh and hardened properties such as slump flow and compressive strength of SCC. The full quadratic equation of a model can be used to assess the influence of constituent materials on the properties of SCC. Moreover, these 28-days observation records are considered as SCC dataset. For predicting the properties of SCC, an existing intelligent classification algorithm IREMSVM-FR has been used. In which cement (kg), fly ash (kg), water powder ratio (W/P) and superplasticizer (l/m3) were taken as sources of data, whereas slump flow and compressive strength were the responses. It is revealed from the results that RSM has optimized the test procedures and trials needed for the proportioning of SCC so as to maximize the slump flow and compressive strength effectively than DOE and IREMSVM model have conformed.

Size and Shape effects of testing specimens on the compressive Strength of SCC

To control the quality of concrete during concreting works, there are various moulds that are used for casting concrete samples according to different standards at different countries. And these differences in the shapes and sizes of concrete samples can cause variations in the results of measured compressive strength. Self-compacting concrete (SCC) have a structural strength and high flowability. This material used in modern concrete technology and extensively in the construction applications of high-rise buildings and long-span concrete structures.This research concentrated on the effect of specimen sizes and shapes on compressive strength of High strength SCC, Specimens were normally cured in the Lab. and tested at age of 28 days. Results were plotted, and indicated that for all testing specimens, there was a significant Influence of size and shape of the specimens on the measured compressive strength. Common sizes that have used for testing compressive strength of concrete were investigated; (100 X100 X100), (150X150X150) mm for cubes and (100 X 200), ( 150 X300) for cylinders. To determine the best conversion factors, linear relationship added as a trend line between compressive strength measured based on testing cylinders to that measured based on testing cubes, on the other hand relationships was conducted to relate compressive strength tested on cubes and cylinders of different sizes.

Development of an optimum mix design method for self-compacting concrete based on experimental results

The main objective of this study is to develop an optimum mix design method for self-compacting concrete (SCC) based on experimental results. For this purpose, mix design of self-compacting concrete is formulated as an optimization problem. Given the importance of manufacturing costs of concrete, the total cost of one cubic meter of self-compacting concrete is considered as the objective function in the optimization problem, which must be minimized. Limitation of the 28-day compressive strength and slump flow of self-compacting concrete are considered as the main inequality constraints. To ensure that sum of concrete components makes unit volume, an equality constraint is considered. To formulate the self-compacting concrete mix design optimization problem based on experimental data, forty-two different mix designs of self-compacting concrete are presented and three cylinder specimens are made and tested for each of them. Two mathematical models are developed to estimate the strength and the slump of the concrete and used to define the main constraints in the mix design optimization model. The concrete specimens are prepared in a construction site in Sanandaj in Iran. Considering importance of sand grading on the compressive strength of self-compacting concrete, stone powder is used to improve sand fineness modulus. The sequential quadratic programming is employed to solve the optimal mix design problem of self-compacting concrete based on proposed model. In order to verify the proposed method, the mix design problem is solved for several case studies and then the final optimal mix designs are made in laboratory and mechanical properties of specimens are evaluated. The results show that the proposed method satisfies the mechanical characteristics of the self-compacting concrete, besides minimizing the cost of the concrete and automating the mix design process.

Study of the Effects of Marble Powder Amount on the Self‐Compacting Concretes Properties by Microstructure Analysis on Cement‐Marble Powder Pastes

The marble powder (MP), obtained from waste sludge marble processing, has a high specific surface area; this could mean that it can be used as filler added to self‐compacting concrete (SCC). The aim of this experimental work is to study the effects of the cement‐MP paste volume on the rheology in the fresh state and the hardened properties (compressive strength) of SCC by a microstructure analysis on paste samples with different amounts of MP. For all pastes, the morphological forms and the chemical composition of the main mineral components were analyzed by the scanning electron microscope (SEM) and X‐ray diffraction (XRD). The hydration, microstructure, and mineralogical changes has been studied. Experimental results show that the cement‐MP paste volume has significant effects on the self‐compacting and the self‐leveling properties in the fresh state of SCC. In addition, the paste volume has a significant contribution on the compressive strength of SCC. Results indicate also that the difference in chemical composition between MP and cement have not any contribution on the paste volume effects.

PROPERTIES of SCC in GREEN and GREY STATE

It is customary to use mechanical properties of concrete in application. Very few studies are having been done to determine the Mechanical properties of self-compacting concrete (SCC). The present study is aimed to obtain the mechanical properties of low and medium strength SCC and to compare with high performance concrete (HPC). The relationship between the spilt tensile strength, flexural strengths, modulus of elasticity and compressive strength of SCC can be expressed as ft = 0:48 fc′, fr = 0:79 fc′; E=4500 fc′, respectively, where the split tensile, flexural, compressive strengths and modulus of elasticity are in MPs. It is observed that the relationship between compressive strength and other mechanical properties are almost same in SCC and HPC.

The use of non-destructive tests to estimate Self-compacting concrete compressive strength

The use of non-destructive tests to estimate Self-compacting concrete compressive strength

The Mechanics Properties of Self-Compacting Concrete Using Red-Tile Waste as Substitution of Fine Aggregates

This paper presents the experimental program about the mechanics properties of Self-Compacting Concrete (SCC) using red-tile waste as substitution of fine aggregates. The proportion of red-tile waste substitution was 10 %; 20 %; 30; 40 %; and 50 % of fine aggregates by weight. Viscocrete-10 was used to maintain the workability and flowability of SCC. 72 cylinder specimens with the size of (150×300) mm and 18 beam specimens with the size of (100×100×500) mm were cast and tested in this study. The mechanics properties of SCC that were studied in this research were compressive strength, modulus of elasticity, and modulus of rupture. The compressive strength of SCC was tested at age 7; 14; and 28 days. While the modulus of elasticity and modulus of rupture of SCC were tested only at age 28 days. The result shows that the maximum compressive strength of SCC was obtained using red-tile waste with the proportion of 50 % as substitution of fine aggregates. The compressive strength of SCC using red-tile with the proportion of 50 % at age 7; 14; and 28 days were 64.746 MPa;, 65.564 MPa; and 71.940 MPa, respectively. While the maximum modulus of elasticity and modulus of rupture of SCC were obtained using red-tile with the proportion 50 % at age 28 days, and the modulus elasticity and modulus of rupture were 25863.192 MPa and 7.076 MPa, respectively.

Prediction of compressive strength of self-compacting concrete by ANFIS models

Abstract Many studies predict the compressive strength of conventional concrete from hardened characteristics; however, in the case of self-compacting concrete, these investigations are very rare. There is no study to predict the compressive strength of self-compacting concrete from mixture proportions and slump flow. This paper designs ANFIS models to establish relationship between the compressive strength as output, and slump flow and mixture proportions as input in eighteen combinations of input parameters. The applied dada is taken from 55 previously conducted experimental studies. Effect of each parameter on the compressive strength and its importance level in the developed model has been investigated. Based on the error size in each combination analysis, weighting factor and importance level of each parameter is evaluated to apply the correction factors to get the most optimized relationship. Obtained results indicate that the model including all input data (slump flow and mixture proportions) gives the best prediction of the compressive strength. Excluding the slump flow from combinations affects the prediction of compressive strength, considerably. However it's not as much as the effect of the maximum aggregate size and aggregate volume in the mixture design. In addition, different values of powder volume, aggregate volume and paste content in the mixture reveal different ascending and descending effects on the compressive strength.