Strength Development Ratio Of Untreated And Heat Treated Sisal Fibre Reinforced Medium Strength Ternary Concrete

Abstract

The strength development ratio (𝐅𝐜) of plain concrete and ternary concrete containing three blends of fly ash (FA) and calcined waste crushed clay bricks (CWCCB) as pozzolanas and incorporating 3% volume fraction (𝐕𝐟) of 40mm average length of untreated and heat treated sisal fibre have been investigated. In this investigation, nine variations of concrete and ternary concrete samples were prepared and cast in 150mmx150mmx150mm mould comprising: (1) Plain concrete of 1:2:4 mix ratio, as control specimens (i.e. one part of ordinary Portland cement (OPC) as binder, two parts of river sand as fine aggregate, and four parts of 19mm crushed granite as coarse aggregate), designated as (4C). (2) Concrete specimens of 1:2:4 mix ratio, reinforced with 3% 𝐕𝐟 of untreated sisal fibre (4F). (3) Concrete specimens of 1:2:4 mix ratio, reinforced with 3% 𝐕𝐟 of heat treated sisal fibre (4FH). (4) Ternary concrete specimens of 1:2:4 mix ratio, with binder ratio consisting of 50% OPC + 20% FA + 30% CWCCB and reinforced with 3% 𝐕𝐟 of untreated sisal fibre (4F20/30). (5) Ternary concrete specimens of 1:2:4 mix ratio, with binder ratio as in (4) and reinforced with 3% 𝐕𝐟 of heat treated sisal fibre (4FH20/30). (6) Ternary concrete specimens of 1:2:4 mix ratio, with binder ratio of 50% OPC + 25% FA + 25% CWCCB and reinforced with 3% 𝐕𝐟 of untreated sisal fibre (4F25/25). (7) Ternary concrete specimens of 1:2:4 mix ratio, with binder ratio as in (6) and reinforced with 3% 𝐕𝐟 of heat treated sisal fibre (4FH25/25). (8) Ternary concrete specimens of 1:2:4 mix ratio, with binder ratio of 50% OPC + 30% FA + 20% CWCCB and reinforced with 3% 𝐕𝐟 of untreated sisal fibre (4F30/20). (9) Ternary concrete specimens of 1:2:4 mix ratio, with binder ratio as in (8) and reinforced with 3% 𝐕𝐟 of heat treated sisal fibre (4FH30/20). Water/binder ratio was kept constant at 0.6 for all specimens. The cube specimens were cured by immersion in clean water and tested at 7, 28 and 90 days curing ages. Plain concrete specimens incorporating 3% 𝐕𝐟 of untreated sisal fibre enhanced the strength development ratio by 65%. Heat treatment of sisal fibre caused an overall reduction of the strength development ratio.