Structural Characteristics Of High Volume Flyash Concrete Subjected To Elevated Temperature

Abstract

Fly ash is a constituent included in concrete batches to enhance their durability and compressive strength. The increased temperatures induced a chemical reaction in the gel, resulting in a reduction in the strength of fly soil concrete. The deterioration of the matrix bonding was the cause of the decrease in strength. There are many techniques by which fly ash may be incorporated into concrete. This material has the ability to substitute a portion or the whole of the fine particles, a portion or the entirety of the cement, or even function as an additional component that improves the formation of certain characteristics in the concrete. Numerous international enterprises heavily depend on pozzolanic concrete, especially those operating in the nuclear, oil and gas, and electrical sectors. Pozzolanic concrete is also used in the construction of bridges and tunnels. Considering their extended exposure to the external environment, these concrete slabs not only experience elevated internal temperatures but also carry an inherent risk of fire. Although concrete is not prone to immediate combustion, it may nonetheless suffer substantial damage or even collapse when subjected to very high temperatures. This work investigated the modulus elasticity, split tensile strength, and compressive strength of fly ash concrete at temperatures up to 120 degrees Celsius. The study used a water-to-cement ratio of 0.5 weight per unit mass and a mixture ratio of 1:1.45:2.2:1.103. Throughout this investigation, fly ash was used as a substitute for cement in many methodologies. Furthermore, measurements were taken for the elastic modulus, compressive strength, and split tensile strength of the substrate. The proportion of cement used determined the replacement ratios, which varied between 30% and 50%. The compressive strength, split tensile strength, and elastic modulus of several types of fly-ash concrete were determined at varying temperatures and after varying curing durations ranging from 28 to 56 days. The results indicated that the compressive strength, split tensile strength, and elastic modulus of the concrete were similar to those of the standard concrete without fly ash, up to a cement replacement level of 30%. The control mixture exhibited superior performance in split tensile strength, elastic modulus, and compressive strength compared to concrete mixes using 30%, 40%, or 50% fly ash as a substitute for cement. Regardless of the historical point at which the pairings were established, this statement remained valid. Conversely, the effectiveness of a combination will increase with time. Concrete mixes with 30%, 40%, or 50% fly ash instead of cement exhibit compressive strength reductions of 11.4%, 30.1%, 28.9%, and 27.5%, respectively, at a temperature of 120 degrees Celsius, in comparison to compositions without fly ash.