Properties Of Self-compacting Concrete Research Articles

Permeability of self-compacting concrete made with recycled concrete aggregates and Portland cement-fly ash-silica fume binder

Permeability properties of self-compacting concrete (SCC) made with fine recycled concrete aggregates (FRCA), coarse recycled concrete aggregates (CRCA), and Portland cement-fly ash-silica fume binder are reported. Fresh and permeability properties of various SCC mixes were assessed. The results indicate that the increase in content of fine and coarse recycled concrete aggregates (RCA) in SCC tends to deteriorate the workability and permeability properties. The compressive strength also decreased with the inclusion of RCA. The substitution of 50% CRCA and 25% FRCA in SCC mix shows marginal decrease in hardened SCC properties as compared to SCC made with fine and coarse natural aggregates. Further, increase in FRCA content in SCC mix deteriorated the compressive strength and permeability properties. Furthermore, the addition of SF at 10% by weight of ordinary Portland cement was able to compensate the loss of permeability properties even for 50% substitution of both FRCA and CRCA.

Properties of Self-Compacting Concrete Incorporating Silica Fume and Fly Ash. (Dept. C)

Properties of Self-Compacting Concrete Incorporating Silica Fume and Fly Ash. (Dept. C)

Investigations of Mixing Technique on the Rheological Properties of Self-Compacting Concrete

Rheological properties are of significant importance in successful placement and performance of self-compacting concrete (SCC). In this work, the rheological properties of SCC, combined with a powder-viscosity modifying admixture, were investigated based on a series of experimental studies. The modified Bingham model was applied to determine the rheological parameters and shear thickening behavior of SCC. The effects of mixing procedures, including charging sequence, mixing time and mixing speed, were analyzed. The results show that the shear thickening of SCC is reduced by first mixing the aggregate and water and then adding other raw materials. The direct contact between aggregate and water leads to a large amount of free water to be adsorbed by the aggregate system, resulting in an increase of the yield stress. In order to ensure an excellent fluidity and a low shear thickening behavior of SCC, the mixing time should be controlled at 4–5 min and the mixing speed at 30–45 r/min.

Predictive Modeling and Multi-response Optimization of Physical and Mechanical Properties of SCC Based on Sand’s Particle Size Distribution

This paper focuses on the modeling and optimization of the physical and mechanical properties of self-compacting concrete (SCC), prepared using the modified packing model design, taking into consideration sand’s particle size distribution (PSD) and fineness modulus (FM). The optimization is predicated using the response surface methodology. The analysis of variance is exploited to determine the statistical significance of the PSD on the studied properties of SCC. For that, we studied twenty-four SCC mixtures, using three kinds of sands with different FM and particle shapes: dune sand, river sand, and crushed sand. The results show that PSD properties of used sand, despite its shape, are good predictors for SCC fresh properties, but less predictive for compressive strength. The multi-response optimization allowed the estimation of sand’s PSD parameters that give the optimal physical and mechanical properties of SCC, with an overall desirability of 0.923.

Study of Properties of Self-Compacting Concrete with Cement replaced with Aluminum Oxide and Silica Fume

Study of Properties of Self-Compacting Concrete with Cement replaced with Aluminum Oxide and Silica Fume

INVESTIGATION OF EFFECTS OF RECYCLED AGGREGATES AND BLAST FURNACE SLAG ON PROPERTIES OF SELF-COMPACTING CONCRETE

The effects of simultaneous use of recycled aggregates and ground blast furnace slag as a percentage of cement-constituting materials on different properties of fresh self-compacting concrete (SCC) are investigated in this study. To this end, three series of SCC mixtures with a fixed volume of cement paste equalling 380 ltr/m3 (2.36 gal/ft3) and the replacement ratio of coarse aggregates (fifty percent and one hundred percent) and total aggregates (zero percent, fifty percent and one hundred percent) were prepared. The water content ratios in the first, second and third series were 0.4, 0.45, and 0.5, respectively. The results of the compressive strength tests for 7-day, 14-day and 28-day cubic specimens and compressive strength and Brazilian test results for 28-day cylindrical specimens were used as control parameters governing the SCC resistive quality. The results of fresh SCC tests (including slump-flow and T50 tests, V-funnel test, and L-box test) showed that the negative effect of recycled fine aggregates on fresh SCC properties is significantly more than that of recycled coarse aggregate. However, recycled SCC with acceptable properties can be obtained with a slight increase in the amount of superplasticisers used in the presence of slag.

The Influence of the Nature of Different Sands on the Rheological and Mechanical Behavior of Self-compacting Concretes

Self-compacting concretes represent a new advance for concrete construction because they offer many advantages from the economic, technical and social point of view. They are very fluid concretes, which are put in place without vibration. When pouring into a formwork, tightening a BAP is ensured by the simple effect of gravity. Thanks to their formulation, they offer exceptional flow characteristics and filling formwork while resisting perfectly segregation. Homogeneous and stable, they have resistances and durability similar to those of traditional concretes of which they are differentiated by their properties in the fresh state. The use of self-compacting concrete reduces the noise nuisance, as well as the hardness of the work. This research work is part of a policy of contributing to the improvement of the properties of self-compacting concretes prepared from local materials in the M’sila region. In this study, we are interested in obtaining the most suitable concrete formulation for the different local materials of the M’sila region. Our study is directed towards the effect of the following parameters on the physico-mechanical properties of the composite such as: dynamic segregation, spreading diameter as well as mechanical strengths (compression, traction). It is therefore a question of determining the criteria to be imposed on these parameters, in order to lead to the construction of a self-compacting concrete characterized by an acceptable resistance. The experimental results of compressive strengths show significant behaviors between BAP and BV. They allowed to distinguish a resistance gain between 15.11 and 49.28, this gain is explained by a rehydration of the cement matrix due to the migration of the water through the pores for the BAP, but also to better binding properties of the hydrates forms.
 Keywords: SCC, Rheological behavior, Mechanical resistance, Binder

Rheological and mechanical characterization of self-compacting concrete with utilization of supplementary sustainable cementitious materials

Self-Compacting Concrete (SCC) being a sustainable high-performance concrete capable of flowing through congested reinforcement and can fill the shuttering without any external energy. The investigation focuses on the effect of waste materials generated from industries on the fresh and mechanical properties of SCC. Experiments were carried out to develop SCC by using Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) as Supplementary Cementitious Material (SCM). Light weight Perlite Aggregates (PA) were used as a partial replacement material in M-Sand. Workability tests were conducted to check the rheological properties of developed SCC mix in accordance with the European Federation of National Associations Representing for Concrete (EFNARC) guidelines. An optimal mix was developed satisfying the criteria as per EFNARC. The developed mix design exhibited a significant reduction in cement content. Ordinary Portland Cement (OPC) was replaced with 31% of FA and GGBFS is kept constant at 31%. The specimens were cured in water under ambient temperature. Performance of the developed mix in terms of compressive strength at different ages of 7, 28, 56 and 90 days were also examined. The results showed that SCC developed with industrial wastes provide adequate workability and strength with a substantial reduction in the cement content. Hence, the developed SCC with FA and GGBFS along with PA can be used as a sustainable concrete due to its high strength for the infrastructure development.

Farklı Mineral Katkılı Kendiliğinden Yerleşen Betonların Taze ve Sertleşmiş Özellikleri

Self-compacting concrete (SCC) is developed with the idea of improved flowability of the fresh concrete mixture. The new technology in plasticizing agents and special mix design of concrete has given this opportunity without any segregation and bleeding. In addition to ease of placement, reduction in the construction time, labor costs and construction noise are the other benefits of SCC. The aim of this study is to investigate the fine mineral additive effect on the fresh and hardened properties of the SCC. For this reason, ground granulated blast furnace slag, fly ash, Bilecik marble powder and calcareous aggregate crushing powder is used as fine powder source in SCC mix designs. Fresh properties of the SCC mixtures are evaluated by performing fresh unit weight, slump flow, V-funnel, and L-box tests. The hardened properties of the prepared SCC are evaluated with the unit weight, ultrasound pulse velocity and compressive strength tests on the 150x150x150 mm cubic specimens at the end of the 3, 7 and 28 days of curing periods. The experimental work showed that ground granulated blast furnace slag and fly ash are more effective on the consistency of the fresh SCC properties. Especially the passing ability of the SCC is improved by using fly ash as a powder in the mix design. The compressive strength of the SCC is developed by using ground granulated blast furnace slag in the mixture. The marble dust is also effective and beneficial for the cohesion and cost of the SCC.

Effect of the polycarboxylate based water reducing admixture structure on self-compacting concrete properties: Main chain length

In this study, the effect of polycarboxylate ether-based water reducing admixture (WRA) main chain length on fresh state properties, compressive strength, ultrasonic pulse velocity (UPV) and water absorption capacity of self-compacting concrete (SCC) mixtures were investigated. Within this aim, three polycarboxylate ether-based high range WRAs with stabilized polyethylene oxide side chain molecular weight, free non-ionic content and constant anionic/non-ionic ratios, but different main chain length were synthesized. FTIR (Fourier transform infrared) and GPC (Gel Permeation Chromatography) analyzes were carried out to characterize admixtures. According to test results, the admixture requirement for reaching targeted main chain length in SCC increased and adsorption of admixture decreased in case the admixture main chain length is higher and lower than a certain value. However, time-dependent flow performance of the mixtures improved with the increase of admixture main chain length and a reverse situation was observed when the length was decreased. Similar behaviors were also observed in V funnel flow, L box and U box passing tests. While the admixture main chain length change affected early age strength, it showed no effect on the strengths of later ages. No considerable differences were observed in the 28-day water absorption, UPV and dynamic modulus of elasticity values of the mixtures with the change of admixture main chain length.

The Properties of Self-Compacting Concrete Using Fly Ash from Hongsa Power Plant

This paper presents the investigation of properties of fresh and hardened concrete which combines of two cementitious materials, Ordinary Portland Cement (OPC) and Fly Ash (FA) from Hongsa Power Plant. The mixed proportion of concrete has been designed for 0.38 of water-binder ratio (w/p) and the replacement ratio of FA to OPC is 5% to 40% by mass which steps every 5% of FA. The total binders in the mixed proportion is 445kg/m3. The water reducing admixture which is Modified poly carboxylate type was used. The slump flow, T500, V-funnel and L-box were tested for investigation of the properties of fresh concrete. Then, compressive strength and tensile strength of concrete at 28 days of age were carried out for examining the hardened concrete properties. The results of study show that using cement combining with fly ash from Hongsa Power Plant improved the rheology of fresh concrete and the hardened concrete properties also have been improved dramatically.

Influence of mixing time and superplasticizer dosage on self-consolidating concrete properties

Self-compacting concrete (SCC) requires specific properties, such as fillability, flowability, and passability. It also needs to resist bleeding and segregation, which may be caused by increased water or superplasticizer (SP) content. In addition, long periods of mixing deteriorate the properties of fresh SCC and causes difficulty in filling structure sections. This study investigates the effect of different mixing periods (e.g., 15, 30, 60, and 90min from the addition of water to the mixture) and increased SP doses (e.g., 1.5%, 2%, 2.5%, and 3% of cement mass) on the properties of SCC mixtures. The properties of fresh concrete were assessed by seven tests, namely, slump flow, V-funnel, slump flow T50, V-funnel T5, L-box, bleeding, and segregation. Hardened concrete was assessed on the basis of compressive, indirect, and flexural strengths. Results showed that compared with the slump flow under 15min mixing time, the 30, 60, and 90min increase in mixing time reduced slump flow by 6%, 19%, and 27%, respectively. Findings also showed that results of SCC segregation and bleeding decreased when increased mixing time. The results also appeared that compressive strength of SCC slightly decreased compared with that under 15min mixing time. The increase in dosage of superplasticizer has mitigated the negative effect for long mixing periods on the properties of concrete.

Effect of high temperatures on physical and compressive strength properties of self-compacting concrete incorporating palm oil fuel ash

Palm oil fuel ash (POFA) has been widely utilized to replace cement in self – compacting concrete (SCC) to reduce the cost of its production, environmental pollution and health hazard caused in the cement production. However, the effect of high temperatures on SCC incorporating POFA has not been well established. The purpose of this research is to examine effects of high temperatures on the physical and compressive strength properties of SCC incorporating POFA with replacement level of 20% by weight of cement. The compressive strengths of SCC specimens were evaluated at 28 days of curing using both cubes and cylinders. Thereafter, the SCC specimens were exposed to high temperatures of 200, 400, 600 and 800 °C using an electric furnace for a period of 2 hours after attaining the required temperatures. After exposure, mass losses together with residual compressive strength were determined. The results of the test showed that there was a continuous reduction in mass of the specimens with increase in temperature. The results also revealed that the colour of the specimens does not change at 200 °C but the colour changes started to occur between 400 °C up to 800 °C. There was an increase in the residual compressive strength for the two mixes at temperature range of 200 – 400 °C for the cubes and cylinders whereas at the temperature of 400 – 600 °C and 600 – 800 °C, there was a sharp reduction in the residual compressive strength for the two mixes for the cubes and cylinders. The SCC with and without POFA follow the same trends.

Fresh State and Mechanical Properties of SCC-POFA-CF Mixture

This paper presents the fresh state and mechanical properties of self-compacting concrete (SCC) with addition of coir fiber (CF) as filler in range of 0.2% to 0.6% and replacing the cement in 10% with palm oil fuel ash (POFA). The workability test such as slump flow and J-ring test were used on the fresh SCC-POFA-CF mixture. The mechanical properties of SCC- POFA-CF in form of compressive, tensile and flexural strength were determine using the compressive test on cube, split tensile test on cylinder and four-point bending test on prism respectively. The increasing amount of CF in mixture resulting the decreasing of workability of SCC-POFA-CF. The SCC mixture with 0.2% CF was selected as optimum as the strength reached the allowable limit of strength. The less crack was occurred on SCC-POFA-CF compared to the control specimen. Therefore, the propagation of crack in prism of SCC was control by coir fiber.

Delayed Strains and Mechanical Properties of Self-Compacting Concrete with Waste Filler of Bituminous Mixtures

AbstractThe valorization of residue from industrial processes for their use as components of other materials is seen as a highly effective solution for environmental problems associated with the bu...

Designing high impact-resistance self-compacting concrete by addition of asphalt-coated coarse aggregate

The brittle fracture characteristic of conventional cement-based concrete poses a great challenge to the security of concrete structures under impact loads. In this study, a new design method is proposed to optimize the impact resistance of self-compacting concrete (SCC) by precoating coarse aggregates with an asphalt-based energy-absorbing layer. The dynamic mechanical properties of SCC with asphalt-coated coarse aggregate (ACCA) were investigated with a 75-mm-diameter split Hopkinson pressure bar. The impact toughness index is defined to evaluate SCC’s impact-resistance performance. Results show that the dynamic increase factor of compressive strength (DIFc) increases linearly with decimal logarithm of strain rate, indicating remarkable strain rate effect. The incorporation of ACCA significantly increases the impact toughness index of SCC, showing a significantly optimized impact resistance. The optimal thickness of asphalt layer is 120 μm, in which the average increase rates of impact toughness index is about 20%.

Effects of waste sulfur content on properties of self-compacting concrete

Self-compacting concrete (SCC) contains fine mineral fillers such as limestone powder. The idea of this study was to partially replace limestone with waste sulfur since it is hydrophobic, insoluble in water and therefore chemically inert and to compare the properties of produced concrete samples. Fresh concrete proper­ties included: slump-flow, t500, V-funnel time, L-box ratio, segregation ratio, density, and entrained air content. Hardened concrete was tested for compressive, flexural and bond strengths, ultrasonic velocity, dynamic elas­ticity modulus, dynamic Poisson’s ratio, and microstructure. Flowability and segregation increased, while bulk density, compressive and flexural strength, dynamic elasticity modulus and ultrasonic velocity slight declined. Times t500 and V-funnel time, L-box ratio and entrained air changed insignificantly. Considering that all proper­ties should remain or improve in case of waste valorization and the criteria should set to satisfy requirements for SCC, this study proved that all mixtures can be used for structural applications.

Effect of Blending Micro and Nano Silica on the Mechanical and Durability Properties of Self-Compacting Concrete

The appropriate utilization of industrial waste materials like fly ash and silica particles from thermal power plants and ferrosilicon industries could be effectively used as partial supplementary cementitious materials. The fly ash was used as binary blends in the cement followed by micro silica and nano silica as ternary and quaternary blended materials in cement system of self-compacting concrete (SCC) respectively. As SCC possess high flowability, passing ability and resisting ability against segregation. The cement was replaced partially by weight from 5% to 15% by micro silica and 1% to 3% nano silica correspondingly. The behaviour of SCC at fresh state was determined using the following laboratory investigations (slump test, V-funnel and J-ring tests). The mechanical properties like compressive strength and flexural strength were analysed for different ages of concrete. The durability characteristics were identified by conducting the saturated water absorption test and the chloride penetration through rapid examination was carried out for all types of SCC mix proportions. The SCC mix containing 2% nano silica and the combination mix of 10% micro silica with 2% nano silica showed a comparable strength increase of 9.28% and 10.84% at 90 days. The addition of nanosilica enhanced the durability properties with less water absorption and decreased depth of chloride penetration.

Improving the Properties of Self-compacted Concrete with Using Combined Silica Fume and Metakaolin

The viscosity is the main property of self- compacted concrete (SCC) and using of pozzolan material such as metakaolin (MK) and Silica fume (SF) can help to achieve that goal. The effect of simultaneous substitution of MK and SF instead of cement on the rheological and mechanical properties of self-compacted concrete was experimentally investigated in this paper. Seventeen mix designs were cast with a substitution weight percentage (5, 10, 15, 20 %) in water to adhesive material ratio equal 0.32. All mixes were examined by compressive, tensile strengths and water absorption tests with an appropriate fluidity, without having signs of segregation or instability. The test results were indicated that the SCC mixes containing MK and SF had higher compressive and tensile strengths in comparison with no-pozzolan concrete. The comparison of linear multiple regression techniques (LMRT) and nonlinear multiple regression technique outputs with experimental results showed an appropriate similarity.

Experimental Investigation on the Mechanical Properties of Self-Compacting Concrete under Uniaxial and Triaxial Stress.

To explore the influence of fly ash (FA) and silica fume (SF) on the mechanical properties of self-compacting concrete (SCC) under uniaxial and triaxial, the compressive strength test, splitting strength test, ultrasonic testing test, and triaxial test were performed in this paper. The results show that the 3 days compressive strength and splitting strength of SCC decreased with the increase of FA substitution rate. The 28 days, 56 days, and 91 days compressive strength and splitting strength of SCC increased first and then decreased with the increase of FA substitution rate. The peak stress and peak strain of SCC gradually increased with the increase of confining pressure. The peak stress and strain of SCC increased first and then decreased with the increase of FA substitution rate. Moreover, the relationship models between compressive strength and splitting strength, between compressive strength and amplitude, between peak stress, peak strain and confining pressure under different FA substitution rates were proposed. As a conclusion, the addition of SF can increase the strength of SCC obviously. Under uniaxial stress, SCC failure mode is splitting failure, under triaxial stress, SCC failure mode is shear failure. Based on the Mohr-Coulomb strength theory, the failure criterion of SCC with FA and SF was discussed.