Sintering of cement concrete and Alkali Activated Concrete

Abstract

Concrete, as the backbone of modern infrastructure, plays a crucial role in the construction industry, yet its environmental impact, primarily due to the high CO2 emissions associated with Portland cement production, necessitates the exploration of more sustainable alternatives. Alkali Activated Concrete (AAC) has emerged as a promising substitute, offering reduced environmental footprints. This thesis investigates the effects of sintering techniques on the mechanical and durability properties of both traditional Cement Concrete (CC) and Alkali Activated Concrete (AAC). It is to be mentioned that, sintering, a technique involving the compaction and solidification of materials through the application of heat and pressure, was explored to enhance the properties of these concrete types. In this study, concrete specimens of varying grades (M20, M25, M30) were prepared and subjected to different sintering conditions, including normal conditions, application of 20 kN pressure, and a combined condition of 100°C for 5 minutes under 20 kN pressure. The performance of the concrete was rigorously evaluated through a series of tests, including compressive strength, split tensile strength, Rebound Hammer Test, Ultrasonic Pulse Velocity (UPV) Test, sorptivity, and Rapid Chloride Permeability Test (RCPT). Additionally, the microstructural characteristics were analysed to understand the underlying changes brought about by the sintering process. The results of this study reveal that sintering significantly enhances the compressive and split tensile strengths, as well as the durability characteristics, of both CC and AAC. Notably, AAC consistently exhibited superior performance compared to CC, particularly under optimized sintering conditions. The findings underscore the potential of sintering techniques not only to improve the mechanical properties and durability of concrete but also to contribute to the development of more sustainable and high-performance construction materials. This research provides a valuable contribution to the field, highlighting the viability of sintering as a method to optimize concrete formulations, thereby advancing sustainable practices within the construction industry.