Paper Title
Study on The Resistance of High-Performance Concrete to The Selected Chemically Aggressive Environments

Abstract
This paper describes the behaviour of high-performance concretes with a metakaolin admixture during long-term storage in chemically aggressive environments. The results of the experiments confirmed that the designed high-quality concretes are highly resistant against the effects of chemically aggressive environments. By adding highly reactive metakaolin, even higher resistance was achieved and at the same time saving the dose of Portland cement. Concrete with the addition of highly reactive metakaolin showed higher values of compressive strength of about 13 per cent, while the dose of Portland cement was reduced by 20 kg/m3. For the durability of reinforced concrete structures, it is also important that the hydrogen ion concentration (pH) of concrete exposed to aggressive media is higher than 12.4, asthis ensures the perfect passivation of the steel reinforcement. Index Terms - Aggressive environment, durability, dynamic modulus of elasticity, high-performance concrete, metakaolin, physical-mechanical properties, ultrasonic pulse velocity.