Fly Ash Based Geopolymer Composites: Manufacturing and Engineering Properties

Geopolymers are currently attracting widespread attention due to their potential utilization as high performance, environmental friendly and sustainable alternative to Portland cement. The present research reports the manufacturing process and engineering properties of low calcium fly ash based geopolymer composites. Initially, the effect of geopolymer synthesizing parameters such as alkali content, silicate content, water content, sand content,curing temperature and duration of thermal curing on compressive strength have been presented for certain level of understanding regarding geopolymer manufacturing process. Further study on engineering properties of geopolymer composite revealed that %Na2O and SiO2/Na2O ratio of the geopolymer mix considerably affect workability and setting time of fresh geopolymer mix as well as physico-mechanical properties of hardened geopolymer specimens. X-ray diffracton analysis of geopolymer show formation of new crystalline phases like hydroxysodalite and herschelite, at higher alkali and silica content that influenced microstructure and engineering properties. Based on the experimental results a mix design guidelines have been proposed.