Prediction of Mechanical Properties of Quaternary Blended High Strength Concrete Exposed to Elevated Temperature and Aggressive Conditions Using a Transformer Based Regression Model.

The usage of high strength concrete (HSC) in infrastructure exposed to harsh service conditions continuous to increase, however its high cement content creates sustainability concerns, and its brittle nature and vulnerability to shrinkage induced cracking are still not resolved. The combined impacts of several supplemental cementitious materials (SCMs) and fibre reinforcement on the mechanical performance, durability, and dimensional stability of HSC, in particular, have not received much attention. This work investigates the mechanical properties, durability, and drying shrinkage behaviour of quaternary blended high strength concrete reinforced with polypropylene (PP) fibres in order to seal these crucial gaps. To improve sustainability and lower cement use, 30 % of the cement content was replaced with a ternary mixture of fly ash, calcined clay, and silica fume. In order to enhance tensile performance and manage drying shrinkage, both crucial for long-term durability and crack resistance, PP fibres were added. Compressive, split tensile, and flexural strengths were measured at various curing ages, and rapid chloride penetration, acid, alkaline, and marine exposure tests were used to evaluate durability performance. Standard protocols were followed to track drying shrinkage over time. The findings show that using PP fibres and SCMs in concrete greatly increases strength, improves chemical resistance, and successfully lowers drying shrinkage, all of which lessens the likelihood of surface cracking. Additionally, a multivariate regression model based on transformer networks was created to concurrently predict modulus of elasticity, split tensile strength, flexural strength, and compressive strength. The optimum mixture, which produced improved strength and durability, was determined by both model prediction and experimental findings to be 17.5 % fly ash, 5 % calcined clay, and 7.5 % silica fume. Overall, the study demonstrates that quaternary blended fibre reinforced HSC provides a sustainable and well-balanced way to achieve improved mechanical performance, durability, and dimensional stability under challenging service circumstances.