Predicting Long-Term Coefficient of Thermal Expansion of Paving Concrete

The coefficient of thermal expansion (CTE) of concrete is an important parameter that affects the design and performance analysis of concrete pavements. Higher CTE value results in increased curling and related stresses. A 28-day CTE value is used for designing rigid pavements. Though previous studies have revealed that coarse aggregate mineralogy has substantial effects on the CTE value of paving concrete, it is not known yet how CTE value changes with the age of concrete in the long-term. In this study, seven concrete mixes with different coarse aggregate mineralogy are tested in the laboratory and data is analyzed to examine CTE. Results show that limestone has the lowest CTE values compared with other coarse aggregates. Concrete CTE increases from 6.4% to 12.6% as it ages. This increase in CTE may result in increased thermal distresses as concrete pavement ages. Therefore, a single value of 28-day CTE should not be used in the design of concrete pavements. In this study, a prediction model is developed to determine aged CTE incorporating mixture volumetrics and concrete strength properties. The same can be incorporated in Pavement Mechanistic Empirical (ME) Design software to better predict the rigid pavement performance.