Fatigue analysis of rice husk ash and basalt fibre-based sustainable geopolymer concrete in rigid pavements

Abstract

Rice husk ash (RHA) and basalt fibres (B.F.) consume the impendency to augment concrete roads' litheness and elasticity and fabricate supplementary sustainable road surface elucidations. However, the fatigue behaviour of such pavements is not fully comprehended. This critique scrutinizes the mechanical and fatigue concert of RHA, a byproduct of paddy, used as source material in geopolymer concrete for rigid pavement, in the presence of alkaline activator prepared by mixing sodium hydroxide and sodium silicate. B.F., which are the derivative of basaltic rock or volcanic eruption, are used as fibre reinforcement in geopolymer concrete. RHA rich in silica and B.F. rich in alumina proved better combination. The sodium silicate to sodium hydroxide ratio was kept 2.0, the alkaline activator to binder content ratio was kept as 0.4, the concentration of sodium hydroxide was kept as 14 M, superplasticizer was used to increase the fluidity of geopolymer concrete, and the source material used was 500 kg/m3, in control mix RHACM. The various percentages of basalt fibre used were 1, 5, 10, 15, 20 and 25% in mixes RHBF1, RHBF5, RHBF10, RHBF15, RHBF20, and RHBF25 respectively and the results of blends with basalt fibre were compared with the control mix RHACM. The results revealed that RHBF10 achieved higher seven, twenty-eight and ninety-days flexural strength of 43.0, 60.1, and 60.4 Mpa respectively and modulus of elasticity of RHBF10 made the higher value of 49,551 Mpa and the lower amount of Poison's ratio as 0.14 by direct wave test of Ultrasonic pulse velocity. For indirect pulse wave, the RHBF10 achieved a higher amount of 45,615 Mpa and the lower amount of Poison's ratio as 0.13. RHBF1, RHBF5, and RHBF15 also gained flexural strength higher than control mix RHACM, but the mixes RHBF20 and RHBF25 showed a decrease in seven, twenty-eight and ninety-days flexural strength than control mix RHACM.