Mechanical and durability properties of self-compacting mortars containing binary and ternary mixes of fly ash and silica fume

Abstract

In this paper, the results of experimental work on the strength and durability performances of self-compacting mortars (SCMs) manufactured from silica fume (SF) and fly ash (FA) were presented. The cement was partially replaced with 5, 10, 15, 20, and 25% of FA and 5, 10, and 15% of SF as binary mixes. Also, ternary mixtures were prepared by the incorporation of FA and SF at different replacement dosages by weight. In total, 14 different combinations of mixes were studied at the ages of 7, 28, and 180 days. Prismatic samples of size 40 × 40 × 160 mm3 were produced and exposed to water curing to observe mechanical behavior of SCMs. The mechanical properties of SCMs were examined by the tests of compressive strength and flexural strength. Sorptivity, porosity, water absorption, and density were also measured. To evaluate fresh properties of SCMs, mini slump flow diameter and mini V-funnel flow time tests were conducted. The results of the study reveal that increase in the dosage of FA increases SCMs flow but also reduce segregation resistance. The enhancement in flexural strength is the best in the binary mixes of SF10 and in binary mixes of FA. Ten percent replacement of FA shows the best flexural strength performance with a value of 10.21 MPa at the age of 180 days. Compressive and flexural strengths of mortars containing SF and FA reached up to about 86.14 and 10.50 MPa, respectively. © 2019 fib. International Federation for Structural Concrete