Development of bio-based blended ash and fly ash based alkali activated concrete

Abstract

Due to rapid industrialization and urbanization there is a significant increase in manufacturing & application of cement which resulted in high CO2 emissions into atmosphere. This leads to investigate alternative binder with reduced CO2 emissions and better performance. The manuscript elaborates the mix design of novel concrete, wherein the principle raw material used was locally available bio-based Blended Ash (BA) procured from co-combustion process with sodium based alkali activators. Physical, chemical, mineral and morphological characteristics of BA were studied. Beside this, investigation of the influence of parameters such as molarity of sodium hydroxide (NaOH), liquid sodium silicate (LSS) to NaOH ratio, fly-ash (FA) to bio-based blended ash (BA) ratio and method of curing on physico-mechanical properties of alkali-activated concrete for sustainable construction material were studied. Higher characteristic strength was attained with increase in these parameters. Maximum characteristic strength of 42.31 MPa at 28th day is obtained with 8 Molar NaOH, LSS/NaOH ratio of 1.5 and FA:BA as 3. The average flexural and split tensile strength obtained is 3.70 MPa and 2.72 MPa respectively. The experimental investigation of the alkali activated concrete using BA and FA proved to be an efficient solution for zero cement concrete with improved performance.