Papers by Keyword: Self-Compacting Concrete (SCC)

Abstract: Ground Granulated Blast Furnace Slag (GGBFS) is a residual material (waste) from the steel smelting process using Blast Furnace technology which has a chemical composition like cement, namely CaO, SiO₂, Al₂O₃, and MgO. GGBFS can be used as a partial replacement for cement in Self Compacting Concrete (SCC). To increase the crack resistance of concrete, steel wire fiber can be used. Using GGBFS and steel wire waste fibers together in SCC concrete can produce concrete with high performance. This research aims to find the performance of fresh concrete and the mechanical performance of SCC concrete using GGBFS as a partial replacement for Portland cement and pieces of steel wire as added materials. The research was carried out by making concrete test specimens with a water cement factor (FAS) of 0.30, with a steel wire cut fiber ratio of 40 equal to 1% of the weight of the concrete. The admixture used is Polynex HE658 superplasticizer produced by PT Nexco at 0.8% of the cement weight. Test specimens were made with 4 variations of using GGBFS which replaced Portland cement, namely 0% GGBFS, 10% GGBFS, 20% GGBFS, and 30% GGBFS. The research results show that the greater the use of GGBFS in fiber SCC, the greater the filling ability and passing ability of the concrete. The use of GGBFS and superplasticizers can also increase the compressive strength, tensile strength and flexural strength of concrete. The highest compressive strength, tensile strength and flexural strength were produced at a GGBFS variation of 20%. The use of GGBFS and superplasticizer can also reduce cement use by ± 20%.

Abstract: This study looked into the economic production of self-compacting concrete (SCC) using affordable and locally available materials such as fly ash (FA), laterites (LA), and polyethylene terephthalate (PET) fibres. To achieve optimal properties of SCC, Response Surface Methodology (RSM) - Central Composite Design (CCD) was employed. Thus, twenty different SCC mixes were designed with varying input factor combinations (FA: 0–40%, LA: 0-50%, and PET fibre: 0–2%) and tested for six responses (rheological properties, namely slump flow, V-funnel time, and L-Box; and mechanical properties, namely compressive, split-tensile, and flexural strengths test). Mathematical models were created in response to the experimental results and assessed using analysis of variance (ANOVA) test. L-Box, V-funnel, and Slump flow test results showed that while fly ash may improve the flowability of SCC, inclusion of high volume of PET-fibres (above 1%) and laterite (above 25%), has high negative impact on SCC flowability. The results further revealed that inclusion of PET-fibres in SCC largely improves the flexural strength (FS) and split tensile strength (STS) by about 20%. However, high volume of laterite contributes negatively to the strength values. Although SCC’s compressive strength decreased with addition of each or a combination of the three different materials, a combination of 20% fly ash, 25% laterite and 1% PET-fibres can result in strength values that are comparative to that of the control mix. The RSM models developed showed relatively good predictive capabilities especially for the compressive strength, L-box and V-funnel models with adjusted R² values ranging between 0.8 – 0.9. Among all the combinations, it is recommended that 20% FA, 25% LA, and 1% PET fibres be adopted in production of sustainable and cost-effective self-compacting concrete, as it gave relatively stable characteristics compared to the control mix in terms of the strength and rheological properties.

Abstract: This study investigates the substitution of river sand with respect to fly ash in self-compacting concrete (SCC) and its performance on workability, strength, and durability. Various mix designs were assessed through L-box, V-funnel and slump cone test to determine fresh concrete properties. The results indicated that higher fly ash content significantly improved the passing and filling abilities of SCC, as evidenced by increased L-box blocking ratios and larger slump flow measurements, albeit with a higher segregation tendency. The mix with 75% fly ash and 25% river sand (FA75-RS25) demonstrated the best overall performance, showing superior passing ability (L-box ratio of 0.87), excellent filling ability (slump flow of 700 mm), and acceptable segregation resistance. This mix also achieved the highest split tensile, flexural, and compressive strengths, outperforming the control mix (FA00-RS100). Flexural strength results for the FA75-RS25 mix showed significant improvements over time, with values of 7.67 MPa at 28 days, 10.33 MPa at 56 days, and 11.17 MPa at 90 days, compared to the control mix which achieved 5.83 MPa, 7.50 MPa, and 8.17 MPa, respectively. These findings underscore the potential of fly ash as a viable and sustainable substitute for river sand in SCC, enhancing performance and supporting sustainable construction practices. Further research is recommended to explore additional mechanical properties and long-term durability aspects of fly ash-incorporated SCC.

Abstract: The purpose of the current investigation was to lower the CO₂ footprint of an industrial self-compacting concrete mix, which currently consists of CEMI 42.5R solely, without any natural pozzolanas or supplementary cementitious materials. The target compressive strength of the industrial mix needed to exceed 55 MPa at 28 days of curing. In the present study we attempted a 20% reduction of CEMI 42.5R (by total mass of solids) by adding 20% of limestone filler and subsequently added 1% of colloidal nanosilica, aiming (i) at leveraging strength loss due to the reduction of Portland cement, (ii) at providing early strength and (iii) at enhancing the microstructure. A water to binder ratio of 0.42 was selected and superplasticizers were added. Fresh properties were studied in terms of slump-flow test, density and 1-day strength. In addition, the 28 day compressive strength was also tested, meeting the mix design strength requirement. Interestingly, the slump flow was improved, indicating better packing effect, however the compressive strength of the control formulations was higher than that of the nanoenhanced formulation. Further insights are also provided.

Abstract: This paper investigates the bond strength of tension lap splice in the ordinary concrete (OC)beam and self-compacted concrete (SCC) beam. A total of six beam specimens were cast for thebending test. Results indicate that the SCC beam and OC beam present similar bond strength at thelap splice of tension bar. Current code for the tension lap splice is available for the SCC beam. Bothof the SCC and OC beams with transverse stirrups could have ductile flexural behavior in the regionof tension lap splicer. Only minor spalling between reinforcing steel and concrete was found underservice loading, such that the corrosion resistance of the tension lap splice in the SCC and OC beamscould be preserved.

Abstract: Steel fiber reinforced concrete (SFRC) is developed traditionally from ordinary concreteadmixed with randomly distributed steel fibers. The matrix of SFRC is always formed by adjustingthe mix proportion used for the ordinary concrete, which plays the role of controlling the properties ofSFRC. In this paper, the mix proportion of self-compacting concrete (SCC) compared with vibrationcompacted concrete (VCC) is statistically analyzed. A predictive formula for water-binder ratio isproposed in relation to the designed compressive strength of SCC and the cement strength affected bymineral admixtures. It is expected to provide reference for the mix proportion design for flowing andhigh-flowing SFRC.

Abstract: An experimental program was undertaken to evaluate the compressive strength of self-compacting concrete using commercial mathematic program. Sample variation was monitored using an experimental cylinder of concrete measuring 150 mm in diameter and 300 mm in height. This research examined various mixture designs in the laboratory tests with the goal of creating mixtures with desirable flow specification that did not require additional vibration yet provided adequate compressive strength. After 28 days, compressive strength of cylinder concrete determination, a model of Artificial Neural Networks (ANNs) was designed for this research and the results were obtained in this model of ANN. Both experimental tests and mix design program data was analyzed with statistical packet software. The result of statistical analysis has been done in 98.54 percent of confidence interval. It has been seen that the ANN can be used as reliable modelling method for similar experiment.

Abstract: In order to eliminate the main problems of clean water shortage and fine aggregate in the low land areas and the distant islands, it is purpose to utilized the sea water, marine sand and Portland composite cement to produce the high performance Self-Compacting Concrete (SCC), where Portland composite cement containing of fly ash. The evaluation result on the mix design, workability (slump flow, segregation), mechanical properties (compressive strength-static modulus) and hydration process of SCC were discussed.

Abstract: This study focuses on the fracture mechanics aspect of self-compacting concrete, compared to vibrated concrete. The most commonly used experiments to investigate the toughness and cracking behaviour of concrete are the three-point bending test (3PBT) on small, notched beams, and the wedge-splitting test (WST) on cubic samples with guiding groove and starter notch. From the resulting P-CMOD curves (applied load versus crack mouth opening displacement), different fracture parameters, such as fracture energy and fracture toughness, can be extracted. Moreover, using inverse analysis, the σ-w relationship (tensile stress versus crack width) can be derived. This paper lists the results of a series of tests on samples, made of VC, SCC of equal strength, and SCC with identical w/c factor. Subsequently, a comparison of the mechanical characteristics is made, revealing important differences regarding several fracture parameters.

Abstract: Self-compacting concrete (SCC) is a very fluid concrete in which its compaction can take place under the effect of its own weight, without vibration. SCC is characterized by its high volume of paste, and the use of superplasticizers. Very little work is reported in the literature on the use of recycled aggregates in SCC. The main objective of this paper is to study the effect of coarse and fine recycled concrete aggregates on the fresh properties of SCC, by substitution of either 100% or 50% of natural aggregates by recycled aggregates. The effect of substitution of 15% by weight of cement of natural pozzolana on the fresh properties of SCC is also studied. The results have shown that the substitution of 50% or 100% of natural aggregates by recycled concrete aggregates gives SCC with very comparable rheological properties to that of the reference SCC. However, SCC with recycled aggregates are less stable against bleeding. The addition of natural pozzolana decreases workability for both SCC with natural aggregates or with recycled aggregates.