Properties of Glass Fibre Reinforced Geopolymer Concrete

This paper presents results of an experimental program to determine mechanical properties of Glass fibre reinforced Geopolymer Concrete which contains fly ash, alkaline liquids, fine & course aggregates & glass fibres. The effects of inclusion of glass fibers on density, compressive strength & flexural strength of hardened geopolymer concrete composite (GPCC) was studied. Alkaline liquids to fly ash ratio were fixed as 0.35 with 100% replacement of ordinary Portland cement by fly ash. For alkaline liquid combination ratio of Sodium hydroxide solution to Sodium silicate solution was fixed as 1.00. Glass fibers were added to the mix in 0.01%, 0.02%, 0.03% & 0.04% by volume of concrete. Based on the test results it was observed that the glass fibers reinforced geopolymer concrete have relatively higher strength in short curing time (3 days) than geopolymer concrete & Ordinary Portland cement concrete. I. INTRODUCTION With infrastructure development growing, demand for concrete as construction material is on increase worldwide, which ultimately increase the demand for cement. Production of Ordinary Portland cement is highly energy intensive, consume significant amount of non renewable natural resources such as lime stone deposition, coal etc. & about 1.0 ton of carbon dioxide (Co2) is liberated during production of one ton of Portland cement (4 -11). The environmental effects associated with production of Portland cement, created an urgent need to develop alternative binder to make concrete. The development of fly ash based geopolymer concrete is in response for the need of greener concrete. The abundant availability of fly ash worldwide create an opportunity to utilize this byproduct of burnt coal as substitute for Portland cement to manufacture concrete. (5) Davidovits (1988) proposed that an alkaline liquids could be used to react with the Silicon (Si) & Aluminium (Al) in source material of geological origin or in byproduct material such as Fly ash, Metacolin, Ground granulated blast furnace slag (GGBS) Rice husk ash (RHA) etc. to produce binders. (2) Geopolymer concrete does not utilize any Portland cement in it, however the binder is produced by the reaction of an alkaline liquids with a source material which is rich in Silica & Alumina. (3). The geopolymer paste binds the loose course & fine aggregates & other un reacted materials together to form geopolymer concrete.The manufacture of geopolymer concrete is carried out using the usual concrete technology methods (1). High early strength, low shrinkage, freeze thaw resistance, sulphate resistance, & corrosion resistance are the properties of geopolymer concrete. (3) Geopolymer concrete composites are good candidate material of construction from strength & durability considerations. Also bond strength of Geopolymer concrete with rebars is higher than cement concrete. (5) The water absorption of fly ash geopolymer is less than 5% which is low & Apparent Volume of Permeable Voids is less than 12% ( which is classified as good ). (10) Water to geopolymer solid ratio is the most influential parameter to increase strength, & to decrease the water absorption / Apparent Volume of Permeable Voids & water permeability. (10) Fibre reinforced concrete is relatively new composite material in which fibres are introduced in matrics as micro reinforcement so as to improve the tensile cracking & other properties of concrete. (7) Some type of fibres produce greater impact abrasion & shatter resistance in concrete . Addition of glass & polypropylene fibres to concrete increase the splitting tensile strength & compressive strength of concrete by approximately 20-50% (6). The compressive, split tensile, flexural & bond strength of geopolymer concrete with 100% replacement of cement by fly ash have increase as the fibre content increased. The maximum value of all these strengths obtained at 0.03% of fibre content.