Center for By-Products Utilization INFLUENCE OF TYPES OF COARSE AGGREGATES ON COEFFICIENT OF THERMAL EXPANSION OF CONCRETE

The coefficient of thermal expansion (CTE) of a typical concrete-paving mixtures made with six different types of coarse aggregates, obtained from fifteen different sources in Wisconsin, was determined. These aggregates belonged to the basic class of glacial gravel, quartzite, granite, diabase, basalt, and dolomite. A total of fifteen different concrete mixtures were used in this study. Triplicate test specimens from each concrete mixture were used to determine the CTE of concrete at the age of 28 days, in accordance with the provisions of AASHTO TP60. In addition to the CTE test, concrete specimens were also tested for the compressive strength and splitting tensile strength. The two parameters, CTE and splitting tensile strength, are the basic input in the AASHTO’s new Mechanistic-Empirical pavement design method. The study revealed a noticeable variation in the values of the CTE of concrete with different types of aggregates. It was also found that concrete with quartzite aggregate had the highest value of the CTE followed by dolomite, glacial gravel, granite, and diabase/or basalt, respectively. Further, it was also found that the estimated value of the splitting tensile strength of concrete based upon its compressive strength, using the Mechanistic-Empirical design guide, for Level 2 design of the concrete pavements by the * Research Professor and Academic Program Director, University of Wisconsin – Milwaukee Center for ByProducts Utilization; P.O. Box 784, Milwaukee, WI, USA(corresponding author). E-mail: , Telephone: 414-229-6696; Fax: 414-229-6958. Assistant Director, University of Wisconsin – Milwaukee Center for By-Products Utilization; P.O. Box 784, Milwaukee, WI, USA. E-mail: , Telephone: 414-229-6696; Fax: 414-229-6958. Post-doctoral Fellow, University of Wisconsin – Milwaukee Center for By-Products Utilization; P.O. Box 784, Milwaukee, WI, USA. E-mail: , Telephone: 414-229-6696; Fax: 414-229-6958. AASHTO method, was significantly lower (17 – 31%) than its actual experimentally determined value. CE Database subject headings: Coarse aggregate; Concrete; Coefficient of thermal expansion; Splitting tensile strength; Mechanistic-empirical design.