The main purpose of this paper is to present results of a three year research project conducted at The University of Texas at Austin on the development of a test procedure for determining the coefficient of thermal expansion of brick under service conditions in a structure. Many currently used masonry design and construction practices are the result of past experience. With the development of new design methods and construction techniques for brick masonry, a better understanding of the thermal behavior of brick is needed. Unaccounted thermal-induced movements in brick masonry have been the reason for observed cracking in brick masonry walls in many structures in service today.

In the study reported herein, the effects of moisture conditions including dry, 50 percent of saturation, and saturated, and of number of temperature test cycles ranging from −18 to 60°C (0 to 140°F) under a given moisture condition on the observed thermal behavior of new (unused) bricks in three directions (length, height, and width) was determined. Strain gages bonded to the surface of each specimen in the direction of measurement were used to monitor temperature-induced movements in the brick continuously during testing. The effect of location of the strain gages on the surface of the brick in each direction on the observed behavior was also determined. The thermal behavior of several brick specimens removed from existing structures after years in service was also observed in order to correlate the results obtained using new brick specimens.

A proposed test method in the form of ASTM standards was developed for determining the coefficient of thermal expansion of bricks under expected service conditions in the structure. Information obtained from this test is needed by practicing engineers in the design of expansion joints in brick masonry to ensure safe and durable structures.