Fresh Properties Of Self-compacting Concrete Research Articles

Modelling fresh properties of self-compacting concrete using Neural network technique

The purpose of this paper is to investigate the feasibility of using artificial neural network programming for the prediction of the fresh properties of self-compacting concrete. The input parameters of the neural network were the mix composition influencing the fresh properties of self-compacting concrete namely, the cement content, the dosages of limestone powder and water, fine aggregate, coarse aggregate, and superplasticizer, and other parameter of time of testing (5, 30 and 60 minutes after addition of water). The model is based on a multilayer feed forward neural network. The details of the proposed ANN with its architecture, training and validation are presented in this paper. Six outputs of the ANN models related to the fresh properties were the slump flow, T50, T60, V-funnel flow time, Orimet flow time, and blocking ratio (L-box). The effectiveness of the trained ANN is evaluated by comparing its responses with the experimental data that were used in the training process. The dosage of water was varied from 188 to 208 L/m3, the dosage of SP from 3.8 to 5.8 kg/m3, and the volume of coarse aggregates from 220 to 360 L/m3 (587 to 961 kg/m3). In total twenty mixes were used to measure the fresh properties with different mix compositions. ANN performed well and provided very good correlation coefficients (R2) above 0.957 for slump flow, T50, V-funnel flow time, Orimet flow time, and L-box blocking ratio. The predicting results for T60 was slightly lower (R2=0.823). With the calculated models these properties of new mixes within the practical range of the input variables used in the training can be predicted with an absolute error for slump flow, T50, T60, V-funnel flow time, Orimet flow time, and L-box ratio of 3.3%, 13%, 16%, 14%, 15%, and 22%, respectively. The results show that the ANN model can predict accurately the fresh properties of SCC.

Usability of Fuzzy Logic Modeling for Prediction of Fresh Properties of Self-Compacting Concrete

Usability of Fuzzy Logic Modeling for Prediction of Fresh Properties of Self-Compacting Concrete

Comparative study on flexural behaviour of RCC beam and SCC ternary beams with mineral admixtures

Self compacting concrete (SCC) has an ideal fluid character at the fresh state and becomes solid once it sets/hardens completely when poured on the desired shape of the mould. The increase of workability and the control of segregation were taken care by super plasticizer (SP) and viscosity modifying agent (VMA) dosages. In this paper an attempt was made to study the flexural behaviour of ternary SCC beams. Cement was replaced with two different combinations viz metakaolin (mk)+ground granulated blast furnace slag (ggbs) and silica fume+ggbs. The experimental results of these ternary beams were compared with Conventional Vibrated Concrete (CVC) & SCC control concrete (SCC 0). Fresh properties of SCC like slump flow, spread were studied in accordance with EFNARC guidelines. Flexural strength of concrete was tested at the age of 28days. Load-deflection characteristics were studied at mid span of the beam (L/2). From the results it was observed that SCC ternary blended beams have higher flexural strength and better ductile performance compared to CVC and SCC0 beams.

CERAMIC WASTE POWDER: AN ALTERNATIVE INGREDIENT FOR GREEN CONCRETE

Producing "greener" concrete that meets various construction/industrial needs will have significant positive impacts on both the construction field and the environment. This paper investigates the use of ceramic waste powder (CWP); a waste material from the final polishing process of ceramic tiles, in producing different concrete types; conventional concrete (CV), self-compacting concrete (SCC), and geopolymer concrete. The conducted study highlights the feasibility of using CWP as a cement replacement in producing conventional concrete, as a filler and cement replacement in making SCC, and as a main binder in developing geopolymer concrete. The study signifies the promising opportunities of utilizing CWP as an alternative ingredient in producing green concrete. Different concrete mixtures were prepared and tested for various properties: slump retention for conventional concrete, flowability, passing ability, segregation resistance and viscosity for judging fresh properties of SCC. Strength development for all three concrete types, chloride ion permeability for evaluating the durability characteristics of conventional and SCC, in addition to resistivity test for the produced geopolymer. Results indicated that CWP can be used 10-30% as partial replacement of cement in CV, and 40% in SCC for producing concrete with acceptable fresh and hardened properties. While for the geopolymer a main conclusion was the use of alkali activating solutions with a concentration of 12M to obtain compressive strength for structural applications.

The Effects of Adding Waste Plastic Fibers (WPFs) on Some Properties of Self Compacting Concrete using Iraqi local Materials

This study presents an experimental research of Self-Compacting Concrete (SCC) properties containing waste plastic fibers (WPF). Adding waste plastics which resulting from cutting PET bottles as fibers to SCC with aspect ratio (l/d) equal to (28). To illustrate the effects of WPFs on the SCC, the current study was divided into two parts, the first part shows the effect of adding plastic fibers on the properties of fresh SCC, which include the ability flow, spread, passing and resistance to segregation, and the second part to evaluate the properties of hardened (mechanical) destructive and non-destructive, which include compression strength, flexural strength and ultrasonic pulse velocity test. One reference concrete mix was conducted and eight mixes contain WPF has been producing self-compacting concrete mixers containing a different volumetric ratio of plastic fibers (Vf) % percentages (0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2) %. Three cubes samples were prepared for testing the compressive strength, three prisms were prepared for the test modules of rupture, one cylinder were prepared testing the modulus of elasticity. The experiments show that adding plastic fibers to SCC leads to an increase in the compression strength and modulus of rupture at 28-day as follows (42.30)% and (73.12)% respectively for mix ratio (1.5)% in comparison with the reference mix, which represent the best ratio of fibers, as such the results of testing the fresh concrete containing waste fibers showed that adding these fibers led a reduction in workability for SCC.

Mechanical and Fresh State Properties of Medium Strength Self-Compacting Concrete (SCC) Containing Polypropylene Fibres

Due to the rising demand of infrastructure development, concrete has been one of the vital ingredients in this field considering its flexibility to mould any structural shape and design. This paper investigates the effect of adding polypropylene fibres on the mechanical and fresh properties of self-compacting concrete (SCC). The mechanical property tests were conducted on various SCC specimen which include cubes, cylinders and beams to determine its compressive strength, splitting tensile strength and flexural strength of concrete. The workability of self-compacting concrete in terms of viscosity is determined from slump flow test (Diameter and T500), and V-funnel. The results indicated that the addition of polypropylene fibres improved the mechanical properties of SCC at almost every volume fraction considered in this study. It was also observed that the addition of 0.1% fibre significantly enhanced the splitting tensile strength and flexural strength of concrete. Finally, the overall results indicated that introducing fibres to concrete would result in a noticeable decrease in workability and fresh state properties.

Influence of Fly Ash on the Properties of Self-Compacting Fiber Reinforced Concrete

Self-compacting concrete (SCC) has high flow ability and high resistance to segregation and bleeding. These characteristics facilitate the mixing, casting and finishing of SCC without using compacting or vibrating machines. Adding mineral admixtures, such as fly ash (FA), and superplasticizers improves SCC properties by preventing segregation and bleeding and by increasing rheological parameters. SCC requires high flow ability under the influence of self-weight to completely fill all mold parts for full compaction. This paper discusses the results of an experimental investigation on the properties of SCC and self-compacting fiber reinforced concrete (SCFRC) mixtures with the inclusion of polypropylene fibers (PFs) and containing FA at replacement rates of 0%, 20%, 40%, and 60 % cement mass. The compressive, flexural, and split tensile strengths of the prepared concrete samples were investigated at ages of 7, 14, 28, and 90 days. The workability of fresh concrete mixtures was also studied through segregation, bleeding, slump flow, slump flow T50, L-box V-funnel T5, and V-funnel tests. Results showed that the best properties of fresh SCCs were obtained when FA was added at replacement rates of 20% and 40% cement mass. In addition, the inclusion of PFs at a volumetric ratio of 0.22% decreased segregation and bleeding and improved the flexural and tensile strengths of SCFRCs.

Proportioning, Microstructure and Fresh Properties of Self-compacting Concrete with Recycled Sand

The use of fine recycled aggregates from recycled concrete is limited due to the high absorption of the material and the subsequent reduction in mechanical performance. At the same time, Self-Compacting Concrete (SCC) uses large amounts of fines to ensure its flowability. Therefore, this type of concrete could allow the use of fine recycled aggregates. Hence, the aim of this work is to study the proportioning and the effects in the microstructure and the fresh basic properties of the use of recycled sand to produce SCC. The concrete mixes analyzed incorporate recycled sand (in percentages of 0%, 20%, 50% and 100%) and natural coarse aggregates. The mix design used an equivalent mortar, which allowed obtaining a suitable concrete that could be at the same time comparable between different replacement ratios and usable in real-life applications. During the design of the mixes with the mortars, the workability was measured from 10 min to 90 min using mini-cone and mini-funnel tests and the suitable ones were chosen to perform self-compacting concrete. Once this was done, these mixes were produced at concrete scale, and with these, basic properties were measured. The fine recycled aggregate changes the workability and the rheology of the mortar and concrete. These differences also affect the microstructure in terms of bonding and porosity distribution. There is a severe reduction of compressive and splitting strength as a result of the use of recycled sand, and this could be linked directly to these changes of the microstructure. The recommended substitution ratio with small decrease of mechanical performance is up to 20%.

Modelling fresh properties of self-compacting concrete using neural network technique

Modelling fresh properties of self-compacting concrete using neural network technique

Effect of incinerated sugarcane filter cake on the properties of self-compacting concrete

Filter cake is a major residue of the sugarcane industry; more than 3 million tons of filter cake waste from the sugarcane industry are annually disposed in Thailand. This paper investigates the effect of incinerated sugarcane filter cake (ISFC) on the properties of self-compacting concrete (SCC). Fifteen SCC mixtures were investigated in this study. ISFC was used as a partial replacement of cement from 0%, 10%, 20%, 30% to 40% by weight of Portland cement (OPC). The powder materials were design to have three total powder contents of 450, 550 and 650kg/m3, whereas the water-powder (OPC plus ISFC) material ratio for all mixtures was kept constant at 0.40. The mixtures were designed to produce a controlled slump flow diameter of 700±25mm. Tests were performed on all mixtures to determine the properties of fresh SCC in terms of workability and stability. The mechanical properties of hardened SCC, such as the compressive strength and flexural strength, were also determined. The results show that SCC with 30% ISFC replaced Portland cement with a 650kg/m3 powder content has a compressive strength of more than 30MPa for 28days, which is larger than the compressive strength of mixes with 550kg/m3 and 450kg/m3 powder contents by approximately 24% and 60% at the identical percentage replacements.

The Effect of Temperature on the Properties of Fresh Self-Compacting Concrete

Abstract The rheological properties of self-compacting concrete are closely influenced by temperature and the time. Previous studies which aim was to research the effect of temperature on self-compacting concrete workability, showed that the behaviour of fresh SCC at varying temperatures differs from that of normal vibrated concrete. The paper presents the study of rheological properties of fresh self-compacting concrete mixtures made with portland, blast furnace and component cement. Two types of superplasticizers were used. It was proven that temperature has a clear effect on workability; it can be reduced by selecting the appropriate superplasticizer and cement.

Water Permeation Properties of Self Compacting Concrete Made with Coarse and Fine Recycled Concrete Aggregates

The paper presents results of an experimental investigation carried out on the water permeation properties of self compacting concrete (SCC) containing fine recycled concrete aggregates (FRCA) and coarse recycled concrete aggregates (CRCA) as replacement of fine natural aggregates (FNA) and coarse natural aggregates (CNA), respectively. The replacement levels of CNA with CRCA were kept as 0, 50 and 100 %. For 50 and 100 % replacement of CNA with CRCA, 0, 25 and 50 % FRCA were used in place of FNA. In all the SCC mixes fly ash was used as partial replacement of Portland cement. Properties of fresh SCC were assessed using slump flow test, V-funnel test and L-box test. The water permeation properties of hardened SCC were investigated using initial surface absorption test, water permeability test and capillary suction test. The compressive strength of all the mixes was also determined. The results indicate that increasing the replacement level of CNA with CRCA has been observed to deteriorate the properties of SCC, whereas the replacement of FNA with FRCA up to 25 % has been found to improve the water permeation properties and compressive strength of SCC mixes up to some extent. Results of this investigation lend support to the use of recycled aggregates in SCC.

Utilization of high-volume treated palm oil fuel ash to produce sustainable self-compacting concrete

Palm oil fuel ash is a supplementary cementitious material (SCM) generated from the combustion of palm oil fibers and shells in palm oil mills to produce electricity, and One approach to reduce the carbon dioxide emissions and increase the sustainability of concrete by substitute a significant amount of ordinary Portland cement (OPC) with it. This study conducted laboratory investigations to evaluate the use of high-volume treated palm oil fuel ash (T-POFA) in producing economical and eco-friendly self-compacting concrete (SCC). The concrete mixtures were prepared with 0%, 50%, 60% and 70% replacement (by mass) of OPC with T-POFA at a constant water/binder ratio of 0.35. Self-compactability testing methods were also employed to evaluate the fresh properties of SCC. Compressive strength and drying shrinkage tests were performed and investigated for up to 6 months and 1 year, respectively. An acid attack resistance test was also conducted on the concrete specimens. Results show that the substitution of OPC with high-volume T-POFA can improve the fresh properties of concrete. At an early age, SCCs containing 50%–70% T-POFA have lower compressive strength than the control SCC mix containing 100% OPC. However, the concrete specimens attained a compressive strength equivalent to that of the control at an age of 28 days and an even higher compressive strength at later ages. The specimens containing high-volume T-POFA have lower drying shrinkage and exhibited better performance against aggressive chemical attack. Cost analysis and carbon dioxide (CO2) emission calculation showed that the T-POFA concrete specimens have 8%–12% lower cost and up to 45% lower CO2 emission than the control SCC mix. The results suggest that T-POFA can be utilized as a cement replacement up to 70% in SCC to produce low-cost and sustainable concrete.

FORMING A CORRELATION AMONG THE PROPERTIES OF FRESH SELF-COMPACTING CONCRETE USING FUZZY LEAST SQUARES MODEL

The research presented in this paper was motivated by two problems regarding the properties of fresh self-compacting concrete (SCC). The first problem is that mixture properties can vary owing to different factors (composition, materials, ambient, etc.) and the second problem is that there is usually a restricted group of experimental results. Because of the importance of the properties of fresh SCC mixtures, different tests for determining its passing and filling ability, as well as segregation resistance, have been developed. In this paper, results from V-funnel and slump flow tests conducted on seven different concrete mixtures are presented. As a correlation between the measurements of V-funnel period tv and the slump flow period t500 is usually strong, in this paper, it was expanded using approximate-distance fuzzy least squares method. The goal was to perceive the possible range of these properties and, when applicable, to reduce the number of tests necessary during the production of SCC.

Rheological and fresh properties of self-compacting concretes containing coarse and fine recycled concrete aggregates

In this study, the rheological and fresh properties of self-compacting concrete (SCC) using recycled concrete aggregate (RCA) as both coarse and fine aggregates have been investigated. SCC mixtures were prepared containing natural aggregate replacements at the levels of 0, 50 and 100% for coarse recycled concrete aggregates (CRCA) and in each series of mixtures fine recycled concrete aggregate (FRCA) replacements were varied at the levels of 0, 25, 50, 75 and 100%. In all concrete mixtures, 20% of cement content was replaced with fly ash (FA) and water-to-binder ratio (w/b) was used as 0.32. Herschel-Bulkley and modified Bingham models were adopted in this paper instead of traditional Bingham model to describe the rheological behaviour of SCC with RCA indicating a non-linear and shear thickening behaviour due to lower yield stress close to zero. The influence of RCA replacements on the shear thickening behaviour of SCC was explained using the rheological analyses. The slump flow and T500 time, V-funnel time and L-box height ratio tests were carried out to identify the effects of both CRCA and FRCA utilisations on the fresh properties of SCC. The results reveal that Herschel-Bulkley and modified Bingham models provide well defined rheological representations for SCC with RCA. The self-compactibility characteristics of the concretes are remarkably improved by the replacement levels of CRCA and FRCA used in SCC mixtures.

FUNDAMENTAL PROPERTIES OF SELF-COMPACTING CONCRETE UTILIZING WASTE RUBBER TIRES-A REVIEW

Utilization of waste rubber tires in concrete technology is a popular research topic over the last two decades. Reuse of waste rubber tires in self-compacting concrete leads sustainable construction. Several studies have been conducted on incorporation of waste rubber tires in self-compacting concrete (SCC). This review paper draws general conclusions on fundamental properties of SCC by summarising and comparing many independent research works and justifies weather these waste tire aggregates are possible to utilize in self-compacting concrete or not . From the review it is evident that the waste rubber tire aggregates can be used in SCC as partial replacement of both coarse aggregates and fine aggregates. The result Although the mechanical properties of SCC experiences negative effect for introduction of waste rubber tire aggregates, still performance of rubberized SCC is better than ordinary SCC. Fresh properties of SCC incorporating rubber tire aggregates also is in acceptable limit.

Modelling the fresh properties of self-compacting concrete using support vector machine approach

The main objective of the study presented in this paper was to investigate the feasibility using support vector machines (SVM) for the prediction of the fresh properties of self-compacting concrete. The radial basis function (RBF) and polynomial kernels were used to predict these properties as a function of the content of mix components. The fresh properties were assessed with the slump flow, T50, T60, V-funnel time, Orimet time, and blocking ratio (L-box). The retention of these tests was also measured at 30 and 60min after adding the first water. The water dosage varied from 188 to 208L/m3, the dosage of superplasticiser (SP) from 3.8 to 5.8kg/m3, and the volume of coarse aggregates from 220 to 360L/m3. In total, twenty mixes were used to measure the fresh state properties with different mixture compositions. RBF kernel was more accurate compared to polynomial kernel based support vector machines with a root mean square error (RMSE) of 26.9 (correlation coefficient of R2=0.974) for slump flow prediction, a RMSE of 0.55 (R2=0.910) for T50 (s) prediction, a RMSE of 1.71 (R2=0.812) for T60 (s) prediction, a RMSE of 0.1517 (R2=0.990) for V-funnel time prediction, a RMSE of 3.99 (R2=0.976) for Orimet time prediction, and a RMSE of 0.042 (R2=0.988) for L-box ratio prediction, respectively. A sensitivity analysis was performed to evaluate the effects of the dosage of cement and limestone powder, the water content, the volumes of coarse aggregate and sand, the dosage of SP and the testing time on the predicted test responses. The analysis indicates that the proposed SVM RBF model can gain a high precision, which provides an alternative method for predicting the fresh properties of SCC.

Effect of the paste coating layer and mortar coating layer on the properties of fresh self-compacting concrete

In this study, a distraction model of aggregate skeleton for self-compacting concrete (SCC) based on the local raw materials was proposed. Paste coating thickness (HPCT) and mortar coating thickness (HMCT) were introduced in this model. The mixing proportions of SCC were designed on the basis of HPCT and HMCT. The workability of SCC was investigated by slump flow, U-box, and V-funnel. And rheometer was used to obtain rheological parameters (plastic viscosity and yield stress) of mortars (screening out coarse aggregates from SCC mixes).The results demonstrate that HPCT and HMCT have positive effect on the slump flow and flowing time of V-funnel, and negative effect on T50 and filling height of U-box. And the formulas between rheological parameters of mortars and workability of SCC mixes were fitted in this study. The results indicate that rheological parameters of mortars also influence the workability of SCC mixes.

Effect of Inert and Pozzolanic Materials on Flow and Mechanical Properties of Self-Compacting Concrete

This research investigates the fresh behaviour and mechanical properties of self-compacting concrete (SCC) containing high volume of limestone, metakaolin, silica fume, zeolite, and viscosity modifying admixture. Two fine aggregates with different fineness modulus were also utilized to evaluate the effect of sand’s gradation on the mechanical and flow properties of SCC containing inert and pozzolanic powder. Slump flow, V-funnel for fresh concrete and 5-minute-old concrete, J-ring, Orimet with and without J-ring, and L-box and U-box tests were performed on all 14 fresh concrete mixtures to examine the fresh properties of self-compacting concrete. Compressive strength of hardened specimens was measured at 7 and 35 days and tensile strength was also determined at the age of 28 days. The results show that sand grading significantly affects the fresh properties of SCC. It is also concluded that high volume of active powders including metakaolin, zeolite, and silica fume could not improve both the flow and mechanical properties of SCC at the same time. Limestone can be effectively used as filler in SCC in high volume content. A new set of limits for the L-box and U-box tests for SCC containing silica fume is also recommended as the existing criteria are not satisfactory.

Mixture design approach to evaluate fresh properties of SCC made with various sands

The aim of the present paper is to provide a mixture design modelling to evaluate the effect of different sand types on fresh properties of self-compacting concrete (SCC). A statistical approach was used to highlight the effect of river sand (RS), crushed sand (CS) and dune sand (DS) as proportions in binary and ternary systems in SCC composition. The responses of the derived statistical models are sand packing density (SPD), T500 and J-ring. The resulting mathematical models are used to illustrate the variation of different responses in ternary contours plots with respect to the proportions of RS, CS and DS. This offers flexibility to optimize RS, CS and DS blends with tailor-made of a given property that suit a particular recommendations. Results indicate that SPD of RS can be enhanced by a 40% of CS and 30% of DS proportions. Moreover, it is shown that flowability, measured by J-ring, can be improved by the increase of CS and DS in RS-CS and RS-DS binary systems. Results also indicate that passing ability measured with T500 decreased with the increase of CS proportion and increased with the increase of DS proportion in binary and ternary systems.