Peak and Differential Temperature Estimation in Drilled Shafts Using Thermal Gradient Measurements

ABSTRACT

Temperature rise in curing concrete is a normal occurrence, but excessive temperatures can be detrimental to concrete strength and durability. Whereas high temperature concerns were once only anticipated in larger elements, the use of high-strength, high-cementitious content mix designs has shown that unsafe temperatures can develop in smaller elements as well. Although methods to predict the internal temperature distribution within foundation elements continue to evolve, current methods to determine when temperature limits have been exceeded are cumbersome, often involving cross-bracing or internal frameworks with embedded sensors that impede construction. This paper presents an innovative approach to predict peak and differential concrete temperatures in shafts using standard cage-based thermal integrity measurements; predictions are verified using data from sensors embedded in the concrete across the diameter of eight production drilled shafts. The proposed method addresses the gap between current mass concrete temperature specifications and the ability of practitioners to measure internal temperature to ensure compliance.