Abstract

In this study, properties of limestone cement concrete containing different replacement levels of limestone powder were examined. It includes 0%, 5%, 10%, 15%, 20% and 25% of limestone powder as a partial replacement of cement. Silica fume was added incorporated with limestone powder in some mixes to enhance the concrete properties. Compressive strength, splitting tensile strength and modulus of elasticity were determined. Also, durability of limestone cement concrete with different C3A contents was examined. The weight loss, length change and cube compressive strength loss were measured for concrete attacked by 5% sodium sulfate using an accelerated test up to 525 days age. The corrosion resistance was measured through accelerated corrosion test using first crack time, cracking width and steel reinforcement weight loss. Consequently, for short and long term, the use of limestone up to 10% had not a significant reduction in concrete properties. It is not recommended to use blended limestone cement in case of sulfate attack. The use of limestone cement containing up to 25% limestone has insignificant effect on corrosion resistance before cracking.

Abstract

The presented article describes a case of damage to concrete in the aquatic supports of a hydraulic ash removal bridge in a power plant. Carrying out an assessment of the causes of concrete damage, as well as determining the possibility of the occurrence of corrosive phenomena within it, and thus, consequently, predicting the durability of the building structure and selecting, on its basis, a proper repair-renovation procedure, required a series of essential studies and analyses to be carried out. Therefore, in the analyzed case, a complex study was carried out on the structure as well as tests on samples of concrete cut out, in the form of core drillings, from the damaged structure (among others: macroscopic, microscopic SEM, XRD, DTA, chemical analyses). Based on these studies, the types of corrosion responsible for the analyzed damage were determined.