Effects of fly ash and cement content on rheological, mechanical, and transport properties of high-performance self-compacting concrete

Abstract

Rheological, mechanical, and transport properties of high-performance self-compacting concrete (HPSCC) mixes with different cement contents and fly ash percentages are studied in this research. Different HPSCC mixtures were investigated with cement contents of 400, 450, and 500 kg/m3 and fly ash percentages of 5 %, 10 %, and 15 %. In order to achieve an enhanced durability, the aggregate grading curve was modified and improved based on power 0.45 grading curve. For a better understanding of fly ash effect and comparison purposes, a constant water to binder ratio (w/b = 0.38) was used. The rheological properties were observed through slump flow time and diameter and V-funnel flow time. Mechanical properties including compressive and splitting tensile strength were determined at 7, 28, and 90 days. A comprehensive transport investigation was carried out using water absorption, capillary absorption, chloride ion percentage, and resistivity tests. The results showed a desirable improvement in rheological properties, and the compressive strength improved by about 10 % for 15 % fly ash at 90 days. A relatively significant improvement was also considered in all transport properties by increasing the fly ash percentage and cement content, especially at higher ages.