High temperature mechanical properties of high-strength fly ash concrete with and without fibers

There is an increasing interest in the use of high-strength fly ash concrete (HFAC) due to growing environmental awareness. Knowledge of high temperature material properties is critical for evaluating the fire response of structures. This paper presents the effect of temperature on mechanical properties of plain HFAC and polypropylene fiber-reinforced HFAC (HFAC-P) with a compressive strength of approximately 70 MPa (10.1 ksi). A series of strength tests were carried out to evaluate compressive strength, tensile strength, stress-strain response, and elastic modulus of HFAC and HFAC-P in a 20 to 800°C (68 to 1472°F) temperature range. Results from mechanical property tests indicate that both HFAC and HFAC-P experience significant degradation in compressive and tensile strength, and elastic modulus with temperature. Data generated from tests are used to develop simplified relations for expressing strength and elastic modulus of HFAC and HFAC-P as a function of temperature. The proposed relations can be used as input data in computer models for evaluating fire response of structures made of HFAC with and without fibers.