Properties of Cement and Geopolymer Mortars Reinforced with Glass Fibres

A composite material consists of high-strength fibres incorporated into a matrix. The incorporated fibres act as the primary load carrying constitute, whereas, the matrix keeps them in desired orientation and location. The ordinary Portland cement is generally regarded as a brittle material having low tensile strength and strain capacity. Recently, fibres such as basalt, cotton, asbestos, glass, and carbon fibres were used as an alternative to conventional steel reinforcements. Geopolymer cement was introduced as an alternative to ordinary Portland cement because it possesses reduced carbon footprint, and it effectively utilises industrial waste materials (such as fly ash, slag). On the down side, it tensile and bending strength is poor due to ceramic-like nature and a number of reinforcements (such as glass fibres) have been considered for improving their mechanical properties. In this experimental investigation, glass fibres were added to geopolymer and ordinary Portland cement based mortars in different volume proportions such as 0%, 1.25 %, 1.50 %, and 1.75 % by volume. The microstructure analysis revealed that the addition of glass fibres led to an increase in the porosity of the samples. The fractured samples containing glass fibres experienced multidirectional micro-cracking instead of control sample, which experienced single large crack leading to sample failure. All of the GFRC and GFGP samples showed well-defined stress-strain behaviour influenced considerably by the addition of glass fibres. The GFRC and GFGP samples with 1.25 % of glass fibres experienced minimum cracking and exhibited maximum improvement in the compressive (~43%) and tensile strengths (~55%)