Mechanical Properties of High-Strength Concrete After Heating at Temperatures up to 400 °C

Abstract

AbstractThe paper presents the results of experimental studies of the effect of short- and long-term heating at temperatures of 90, 200, 300 and 400 °C on the strength and deformations of high-strength concrete modified by organo-mineral components (superplasticizer, silica fume and fly ash). It was shown that the compressive strength and the tensile strength of high-strength concrete after heating up to 300 °C have decreased slightly. The addition of silica fume and fly ash has had a beneficial effect on the cement stone and the bond strength between the cement stone and the aggregate.The ultimate deformations of high-strength concrete after heating have increased due to changes in the structure of concrete. It is worth noting that the increase of plastic deformations has associated with the development of micro and macro cracks in the structure of concrete. Based on the obtained experimental data on the longitudinal and transverse strains, the following characteristics have calculated: the modulus of elasticity, a Poisson’s ratio.This work was carried out within the framework of the grant of FNI Ministry of construction of Russia and RAACS on the subject 7.4.15-18 “Fundamental research of the influence of elevated temperatures up to 200 °C on the characteristics of physical-mechanical and rheological properties of high strength modified concrete classes B70 ÷ B90”.KeywordsHigh-strength concreteHeatingStrengthModulus of elasticityPoisson’s ratioDeformations