EXPERIMENTAL STUDY ON STRENGTH DEVELOPMENT AND ADIABATIC TEMPERATURE OF HIGH-STRENGTH CONCRETE FOR BRIDGE PIERS

Abstract

This article presents the design and experimental evaluation of a high-strength concrete mix for bridge pier applications, targeting a compressive strength of 50 MPa. The mix composition was designed according to ACI 211.1-91, incorporating cement, fly ash, blast furnace slag, superplasticizer, and a temperature rise inhibitor. The selected mix achieved a laboratory design strength of 60 MPa. Strength development tests were conducted on cubic and cylindrical specimens at 3, 7, 28, and 56 days. Results showed a compressive strength increase from 35.2 MPa at 3 days to 64.2 MPa at 56 days, while splitting tensile strength improved from 3.12 MPa to 5.19 MPa within the same period. The elastic modulus calculated according to CEB-FIP Model Code 2010, reached 40.47 GPa at 56 days. In addition, an adiabatic calorimeter was designed and improved to monitor the temperature rise of the concrete. Measurements revealed a maximum adiabatic temperature of 76.6°C, corresponding to a temperature rise of 52°C, with the most rapid increase occurring between 8 and 32 hours after casting. The study results provide the necessary data to evaluate the thermal behavior and minimize the risk of thermal cracking in large concrete structures such as bridge piers.