Low carbon building: Experimental insight on the use of fly ash andudglass fibre for making geopolymer concrete

摘要

Due to the environmental impacts resulting from the production of Ordinary Portland cement (OPC), theuddrive to develop alternative binders that can totally replace OPC is gaining huge consideration in theudconstruction field. In the current study, attempt was made to determine the strength characteristics ofudglass fibre-reinforced fly ash based geopolymer concrete. Sodium hydroxide (NaOH) and sodium silicateud(Na2SiO3) were used as alkaline solutions (for activation of geopolymer reaction) at 12, 16, 20 M. Glassudfibres were added to the geopolymer concrete in varying proportions of 0.1e0.5% (in steps of 0.1%) byudweight of concrete. A constant weight ratio of alkaline solution to fly ash content of 0.43 was adopted forudall mixes. British standard concrete test specimens were cast for measuring compressive strength, splittensileudstrength, and flexural strength. Concrete specimens were cured by heating in oven at 90 �C forud24 h and natural environment, respectively. From the results, thermally cured concrete samples hadudbetter mechanical properties than the ambient (natural) cured samples. Thermally cured concreteudspecimen, containing 0.3% glass fibre and 16 M NaoH, achieved a maximum compressive strength ofud24.8 MPa after 28 d, while naturally cured samples achieved a strength of 22.2 MPa. There was substantialudincrease in tensile strength of geopolymer concrete due to the addition of glass fibres. Splitudtensile strength increased by 5e10% in glass fibre-reinforced geopolymer concrete, containing 0.1e0.5%udglass fibre and 16 M NaoH when compared to the unreinforced geopolymer concrete (1.15 MPa).