Modelling and Optimization for Mortar Compressive Strength Incorporating Heat-Treated Fly Oil Shale Ash as an...

Area of Science:

• Materials Science
• Civil Engineering
• Waste Management

Background:

• Fly oil shale ash (FOSA) is a waste byproduct with inherent pozzolanic properties.
• Utilizing FOSA as a cement replacement can mitigate environmental impact and resource depletion.

Purpose of the Study:

• To determine optimal thermal treatment conditions for FOSA to maximize its effectiveness as a cementitious material.
• To evaluate the impact of FOSA incorporation on mortar properties, including compressive strength and pozzolanic activity.

Main Methods:

• FOSA samples were calcined at temperatures from 550°C to 1000°C for 2, 4, and 6 hours.
• Mortar specimens with 10-30% FOSA replacement were prepared and tested for mineralogical, chemical, and mechanical properties.
• Response Surface Methodology (RSM) was employed to model and optimize FOSA performance.

Main Results:

• Calcination at 700°C for 2 hours yielded the highest pozzolanic activity and strength activity index (75%).
• Optimal compressive strength was achieved with 30% FOSA replacement after 56 days of curing.
• The developed RSM model demonstrated high correlation (above 85%) for predicting FOSA performance in cementitious matrices.

Conclusions:

• Thermal treatment significantly enhances the pozzolanic activity of FOSA.
• Optimally treated FOSA can effectively replace up to 30% of cement, improving mortar strength.
• The study provides a robust model for optimizing FOSA utilization in concrete applications.