Influence of Alkali Resistant Glass Fiber on the Reduction of Plastic Shrinkage Cracking of Self Compacting Concrete

Abstract

Plastic shrinkage cracking has become one of the serious problems in concrete elements especially in structures with large surface area/volume ratios and affect the durability of the structure. This paper quantifies the effectiveness of fly ash and alkali resistant (AR) glass fibre on cracking of plastic self compacting concrete. The aim of this experimental work was to study the plastic shrinkage evolution in fly ash based self compacting concrete (SCC) and to examine the effectiveness of alkali glass fibre in SCC to reduce shrinkage cracks. The test was carried out in the mould based on ASTM C1579. At early ages compressive strength of the SCC mixes was similar to that of the reference mix and the maximum strength was observed for 25% replacement by fly ash and is considered as the reference mix. Alkali resistant glass fibres of 12 mm length were added to reference mix of SCC at different dosages of volume fractions of 0.1, 0.2 and 0.3% and the shrinkage test were conducted. The plastic shrinkage test results of Ordinary concrete, reference SCC and SCC mix with various dosages of glass fibre were compared. The SCC mix with AR glass fibre of Volume fraction of 0.2% was found out to be most effective.