Treatment of fly ash to increase its cementitious characteristics

This dissertation focuses on converting fly ash to a cementitious material to be used in making a unique concrete with no use of Portland cement. This new material is called Ashcrete. The role of the treated fly ash in Ashcrete is analogous to that of cement in making conventional concrete. In other words, Ashcrete is a concrete where the cement is substituted with treated fly ash.; The development of Ashcrete consisted of four stages. In the first stage fly ash was chemically treated with sodium silicate solution (SiO{dollar}sb2{dollar} Na{dollar}sb2{dollar}O) and sodium hydroxide (NaOH) at an elevated temperature, producing a zeolitic material. The zeolitic material was then used to produce Ashcrete. This procedure involved two phases of operation, which were time consuming and unstable. The second stage advanced to making Ashcrete in one phase where the treatment and curing take place simultaneously. The mix proportioning and processing procedures were optimized. To reduce energy consumption and improve manufacturing processes, the third stage of the development was to produce Ashcrete without use of any heat during its processing (at ambient temperature). The last stage involved understanding the role of sodium hydroxide (NaOH) in the hardening process of the Ashcrete. This led to the discovery of making Ashcrete without any use of sodium hydroxide (NaOH) at ambient temperature.