Structural behaviour of circular concrete filled steel tube column fill with selfcompacting concrete incorporating coal bottom ash as fine aggregate replacement

Lack of compaction may affect the interaction between the steel tube and the concrete, hence influence the behaviour of CFST column. Employing selfcompacting concrete (SCC) in CFST column as an infill concrete remove the necessity for compaction. However, higher volume of fine aggregate required in SCC makes SCC less preferable. The objective of this research was to investigate the behaviour of circular CFST column filled with SCC incorporating coal bottom ash (CBA) as fine aggregate replacement. In this research work, sand was replaced with CBA at 10%, 15%, 20%, 25%, and 30% of replacement levels. Tests for compressive strength, split tensile strength, flexural strength, and water absorption were performed on specimens at 7 and 28 days curing age. The testing results show that 15% of CBA was the optimum percentage suitable used in SCC. In studying the behaviour of CFST columns, 18 CFST column specimens were tested to fail under the axial compression loading. From the experimental results, it can be concluded that the utilisation of SCC with CBA in the CFST column able to improve the behaviour of CFST column. From compression testing results, the strength of CFST column filled with SCC with CBA increased about 45-50%. The experimental results were also compared with the design standard of Eurocode 4 (EC4). From the comparison, the EC4 conservatively predicts the strength of the column specimens. For instance, EC4 conservatively predicted the column strength in series I by about 21-31%. The finite element analysis (FEA) was conducted on the long column to verify the experimental results and from the FEA result, the predicted value for specimens with 140 mm diameter is 0.005% closer to the experimental results. These discoveries are significant as they showed that the utilization of CBA in SCC as an infill in CFST column able to provide the same strength as CFST with normal SCC. Besides, the use of CBA as partially replacement to the sand will help in more sustainable SCC production by lowering energy and raw material consumption

The Strength Behavior of Self-Compacting Concrete incorporating Bottom Ash as Partial Replacement to Fine Aggregate

Abstract Self-compacting concrete which commonly abbrevited as SCC is a special concrete that have the ability to consilodate fully under its own self-weight without any internal or external vibration. This paper presents the experimental investigation carried out to study the strength of self-compacting concrete incorporating bottom ash at different replacement level of natural sand. The composite cement was used and the replacement level of bottom ash to natural sand is set up to 30 % by volume. The strength properties such as compressive strength, split tensile strength and flexural strength of the concrete at the age of 7 and 28 days of curing day were conducted. Results shows that the strength of the concrete with bottom ash increased up to replacement level 15% higher than control specimens. This show that bottom ash can be used as supplimentary cementitious materials, having the pozzolanic reactivty

Fresh properties of self-compacting concrete integrating coal bottom ash as a replacement of fine aggregates

The influence of coal bottom ash on fresh properties of self-compacting concrete (SCC) were presented in this paper. Self-compacting concrete mixtures were produced by 0.40 water/powder ratio and coal bottom ash as a replacement of fine aggregates in varying percentages of 0%, 10%, 15%, 20%, 25% and 30%. The fresh concretes were tested for the key workability belongings of self-compacting concrete such as passing and filling abilities and segregation resistance. The fresh properties were investigated by slump flow; T500 spread time, sieve segregation and L-box test. It was found that the slump flow decreased whereas the T500 spread time increased with higher coal bottom ash content. The L-box blocking ratios changed from 0.92 to 0.65 and were mostly showed satisfactory blocking ratio. The presence of coal bottom ash improved the stability of SCC mixture and the segregation index obtained from sieve test reduced with greater bottom ash content. It can be concluding that the filling and passing ability of SCC decreased when the amount of coal bottom ash content increased. In addition, the segregation resistance index decreased with higher coal bottom ash content

Fresh characteristic and mechanical compressive strength development of self-compacting concrete integrating coal bottom ash as partial fine aggregates replacement

This paper presents the experimental works to study the effect of use of coal bottom ash as a partial replacement of fine aggregates in self-compacing concrete (SCC). The compressive strength properties studied instead of fresh characteristic of mixtures. The SCC mixtures were produced by three different water cement ratios (0.35, 0.40 and 0.45) and coal bottom ash as a replacement of fine aggregates in varying percentages of 0%, 10%, 15%, 20%, 25% and 30%. The fresh properties were investigated by slump flow, T500 spread time, sieve segregation and L-box test in order to evaluate its self-compatibility. It can be concluding that the filling and passing ability of SCC mixture decreased when the amount of coal bottom ash content increased. The compressive strength development for various percentages replacement of fine aggregates with coal bottom ash was conducted at 28, 90 and 180 days. It is clearly noticeable the progress of compressive strength on intensification of water cement ratio at different curing ages. The increase of water cement ratio decreased the compressive strength for all percentages of coal bottom ash at all ages

Fresh Properties and Flexural Strength of Self-Compacting Concrete Integrating Coal Bottom Ash

This paper presents the effect of using coal bottom ash as a partial replacement of fine aggregates in self-compacting concrete (SCC) on its fresh properties and flexural strength. A comparison between SCC with various replacements of fine aggregates with coal bottom ash showed that SCC obtained flexural strength decrease on increase of water cement ratio from 0.35 to 0.45. The natural sand was replaced with coal bottom ash up to 30% volumetrically. The fresh properties were investigated by slump flow, T500 spread time, L-box test and sieve segregation resistance in order to evaluate its self-compatibility by compared to control samples embed with natural sand. The results revealed that the flowability and passing ability of SCC mixtures are decreased with higher content of coal bottom ash replacement. The results also showed that the flexural strength is affected by the presence of coal bottom ash in the concrete. In addition, the water cement ratios are influence significantly with higher binder content in concrete

Fresh Properties and Flexural Strength of Self-Compacting Concrete Integrating Coal Bottom Ash

This paper presents the effect of using coal bottom ash as a partial replacement of fine aggregates in self-compacting concrete (SCC) on its fresh properties and flexural strength. A comparison between SCC with various replacements of fine aggregates with coal bottom ash showed that SCC obtained flexural strength decrease on increase of water cement ratio from 0.35 to 0.45. The natural sand was replaced with coal bottom ash up to 30% volumetrically. The fresh properties were investigated by slump flow, T500 spread time, L-box test and sieve segregation resistance in order to evaluate its self-compatibility by compared to control samples embed with natural sand. The results revealed that the flowability and passing ability of SCC mixtures are decreased with higher content of coal bottom ash replacement. The results also showed that the flexural strength is affected by the presence of coal bottom ash in the concrete. In addition, the water cement ratios are influence significantly with higher binder content in concrete

Strength behaviour of coal bottom ash self-compacting concrete exposed to cyclic wtting-drying in seawater

This study presents the strength behaviour of the self-compacting concrete which incorporated the coal bottom ash that was exposed to cyclic wetting and drying processes under the condition of seawater environment. The mixtures were produced by combining 0.40 water/powder ratio and coal bottom ash in varying percentages of 0, 10, 15, 20, 25 and 30%. The samples arising from each mixture were exposed to seawater environment with an average of 15 h of wetting process and 9 h of drying process per day. Consequently, the compressive strength behaviour of the concrete at the durations of 28, 60, 90 and 180 days under curing process were observed to understand the physical mechanisms that affected the concrete during the cyclic wetting and drying phases while exposed to harsh environments. The results of the cyclic wetting and drying processes in the laboratory indicated that there were significant strength reductions across all mixtures. It was found that that the strength of 10% coal bottom ash replacement sample is slightly higher than the control samples