WORKABILITY AND FLEXURAL STRENGTH OF CONCRETE REINFORCED WITH BASALT MACRO-FIBERS

Abstract

The effect of using basalt macro-fibers (BMF) rather than basalt fiber filaments on concrete properties has received little attention. The aim of this paper is to examine the workability and tensile properties of normal-strength concrete mixes reinforced with different BMF volume fractions of 0.5, 1, and 1.5%. Compacting factor, slump, and vebe time tests were conducted on fresh concrete mixes to examine the workability of the concrete. Splitting and flexural strength tests were conducted on concrete specimens at 28 days of age to examine the tensile properties. The compacting factor of the BMF-reinforced concrete mixes was up to 14% lower than that of a plain control mix without fibers. The plain concrete exhibited a slump of 220 mm, whereas that of the concrete mixes with BMF was in the range of 50 to 85 mm. The vebe time increased with an increase in the BMF volume fraction, indicating a reduced concrete workability. In contrast, the inclusion of BMF improved the tensile properties of the concrete. The splitting tensile strength gain was in the range of 10 to 52%, whereas the increase in the flexural strength ranged from 18 to 56%. The addition of BMF has also improved the flexural toughness of the tested specimens. The unique flexural test results reported in this paper can be employed in future research along with an inverse finite element analysis to develop tensile softening constitutive laws of concrete with different BMF volume fractions.