IDENTIFICATION OF COARSE AGGREGATES PRONE TO SURFACE DETERIORATION AND D-CRACKING IN CONCRETE PAVEMENTS

Abstract

This study investigates the influence of coarse aggregates on the durability of concrete pavements exposed to freezing and thawing cycles, particularly focusing on the phenomena of surface deterioration and D-cracking. Argillaceous aggregates from Indiana pavements showed significant surface damage within one to two years of construction, despite being from approved sources and the concrete being air entrained for freeze-thaw protection. The deterioration was linked to the aggregates themselves, with no apparent damage to the surrounding cement paste. The research aimed to understand the role of osmotic effects in the aggregates' failure by conducting laboratory experiments to simulate the freezing conditions with and without salt solutions. The findings revealed that the argillaceous aggregates exhibited osmotic phenomena, leading to an additional detrimental mechanism during freezing and thawing when a salt concentration gradient exists. This study confirms the significant impact of osmotic pressure on aggregate failure and suggests a simple testing procedure to identify aggregates prone to such deterioration. The results have implications for the selection and testing of coarse aggregates used in concrete pavements, particularly in environments where deicing agents are applied. (Abstract generated by AI tool ChatGPT 4)