Effect of aggregate particle shape and granulometry on the workability and mechanical properties of glass reinforced concrete

Abstract

Modern alkali resistant glass fibers (ARG) modified with 17% ZrO2 are getting more popular as reinforcement of cementitious matrixes. Typical matrix compositions with quartz, Portland cement, 13 mm length ARG glass fibres and PCE superplasticizer can offer good workability, product quality and highly increased mechanical characteristics. In production of self compacting fibre reinforced premix highly siliceous fine sands with nearly round shape particles are usually preferred. This article investigates influence of particle shape for workability of glass fibre reinforced concrete when alternative fillers- crushed granite and regular sand are used. 12 compositions were made whith different quantities of fillers, changing quartz from 0% to 50% with alternative aggregates. Slump tests according to EN 1170-1 were made and showed major impact of particle shape characteristics on mix workability. When quantity of altrernative aggrates was increased, slump of fresh mix decreased and fibre- matrix segregation occurred. New workability factor W is offered and values calculated, to have numeric representation of workability. Alternative aggregates had no clear influence for flexural strenght, when beams 40×40×160 were tested. Compressive strength dropped by 25% when regular sand was used. Typical quartz matrix resulted in lower water absorbtion.