RESIDUAL STRENGTH AND POST-CRACKING BEHAVIOUR OF GLASS WOOL FIBRE-REINFORCED CONCRETE EMBEDDED WITH STEEL REINFORCEMENT

Abstract

: This study aims to experimentally investigate and present the impact of glass wool fibre (GWF) on the residual flexural strength (RFS) for conventionally reinforced concrete elements by carrying out RFS test on concrete prism specimens. Additional tests, compressive and splitting tensile strength tests were also conducted on cube and cylinder specimens respectively to further examine the effect of the fibre on concrete. Twenty cubes of size 100 by 100 by 100mm, twelve cylinders of size 100 by 200mm and two sets of twelve prisms of size 100 by 100 by 400mm each with and without steel reinforcement (SR) were cast and then cured by water immersion for 28 days after which they were made to undergo compressive, splitting tensile and RFS test (using 3-Point Bending). The GWF content added ranges from 0.00% to 1.00% for four different mixes used. The results showed a significant percentage increase of 20.83% in tensile strength with 0.50% fibre content and marginal increase of 0.26% in compressive strength with 0.25% fibre dosage. The study also showed that combination of conventional SR and GWF in concrete resulted in enhanced residual strength. It was observed that the average RFS of glass wool fibre-reinforced concrete (GWFRC) with and without SR increased with increasing fibre contents up to 0.50% before a decline in the strength was observed with 1.00% fibre dosage. the use of both SR and GWF in concrete should be given more consideration in concrete industry because of the possibility of improved residual flexural strength and as their synergic tensile properties could have positive impact on service life of concrete structures.