Investigation of the effects of high temperature on compressive and tensile strength and modulus of elasticity of alkali-activated concrete

Subject Areas : Analysis of Structure and Earthquake

Mohammadhossein Mansourghanaei ¹

1 - Ph.D. in Civil, Department of Civil Engineering, Chalous Branch, Islamic Azad University, Chalous, Iran

Received: 2022-04-17 Accepted : 2022-07-24 Published : 2022-10-18

Keywords: Compressive Strength, Tensile strength, Modulus of elasticity, Ordinary concrete, Alkali-activated concrete,

Abstract :

In recent years, improving the mechanical properties of alkali- activated concrete with the aim of being superior compared to those of the conventional concrete and reducing environmental hazards caused by the lack of mineral resources and release of toxic carbon dioxide gas (in cement production process) has been noticed by civil engineering researchers. In this laboratory research, a mixing design of ordinary concrete containing Portland cement with a grade of 500 kg/m3 and a mixing design of alkali-activated concrete based on blast furnace slag were made. In order to check the mechanical properties, tests of compressive strength, tensile strength and modulus of elasticity of concrete were performed under the temperatures of 21 and 600 ℃ at the age of 90 days of curing.  Based on the results, applying high temperature (600 ℃) to concrete samples caused a 42% and 15% drop in compressive strength, a 56% and 21% drop in tensile strength, and a 63% and 49% drop in modulus of elasticity for ordinary and  alkali-activated concretes, respectively.  The compressive strength of alkali-activated concrete was 11% and 64% more than that of the normal concrete at 21 and 600 ℃, respectively. The tensile strength of alkali-activated concrete exhibited a 9% decrease and 63% superiority compared to normal concrete at 21 and 600 ℃, respectively. The elasticity modulus of alkali-activated concrete was 16% and 62% higher than that of the normal concrete at 21 and 600 ℃, respectively. The results of the scanning electron microscope images are in accordance with the other test results of this research.