COEFFICIENT OF THERMAL EXPANSION (CTE) AND MODAL MINERALOGY OF NORTH CAROLINA AGGREGATE USED FOR INFRASTRUCTURE APPLICATIONS

North Carolina's diverse geological landscape, shaped by ancient tectonic processes, offers a unique tapestry of rocks that contribute significantly to the aggregate production industry, a vital component in concrete used for construction. This research focuses on understanding the Coefficient of Thermal Expansion (CTE) of North Carolina aggregates, exploring the mineralogical composition of rocks used for aggregate production and its implications for long-term stability of concrete. Concrete with a higher CTE is more prone to premature cracking and deterioration. Aggregate comprises roughly 70% of concrete. Therefore, the primary objective of this study is to determine whether a relationship exists between modal mineralogy and concrete CTE and whether future estimates of concrete CTE can be predicted from aggregate modal mineralogy. Modal mineralogy will be determined using the point count method for 17 samples from aggregate-producing quarries across North Carolina. Published mineral CTE values will be combined with modal mineralogy to calculate a weighted average of CTE for each rock. These modeled values will be compared with measured rock values, which range from 5.112 to 9.119 (10^-6m/m°C). Quartz, feldspar, and mafic minerals are the most abundant minerals found within samples and have average CTE values that range from 11.1 to 36.0 (10^-6m/m°C). This project seeks to bridge mineralogy/petrology with construction engineering sciences, providing valuable insights into whether or not aggregate composition influences concrete stability over time. Ultimately, this research contributes to a deeper understanding of the thermal properties of North Carolina aggregates, with potential implications for sustainable construction practices.