Effect of basalt fiber on self-consolidating concrete with fly ash replacement

Abstract

This work explores the behavior of self-compacted concrete produced with fly ash as cement supplementary material and basalt fibers. A combination of desert dune sand and finely crushed aggregates were used as fine aggregates; the dune sand served as sustainable material as it is a regional material and does not need further pre-processing before use. Further, a maximum size of 10 mm aggregate was used as coarse aggregate. Polycarboxylic ether-based superplasticizer was used at a constant dosage of 1.5% of the total cementitious materials to maintain the targeted flow value with the reduced water-to-cement ratio. The maximum replacement dosage of cement with fly ash was 40%, as most studies recommend this ratio without altering concrete behavior. Basalt-chopped fibers with different percentages ranging from 0.5% to 2% were used as an additive to the mix with the lowest strength results. Conclusions were drawn based on the interpretation and experimental assessment of the workability and strength properties of the concrete. Rheological properties results indicate an enhancement in workability could be attained with the increase of fly ash content; However, a tendency of segregation and loss of stability was observed after a certain threshold. In the meantime, basalt fibers showed an improvement in segregation resistance with loss of workability. The compressive strength results revealed that the optimal fly ash dosage was 20%, with a strength that is comparable to the control mix strength. Meanwhile, the mix with 40% of fly ash content showed a drop in strength of 18% from the control mix, which was regained after adding basalt fiber with an optimal dosage of 1% of the total binder content.