Abstract

Info

Author(s):: QIAO Hong-xia; CHEN Zhi-chao; LIANG Jin-ke; LI Yuan-ke; NDAHIRWA Desire; Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province, Lanzhou University of Technology

Keywords:: basalt manufactured sand; ultrasonic velocity; relative dynamic elastic modulus; ratio of compressive strength

Abstract:: In order to study the sulfate corrosion resistance of the basalt manufactured sand to concrete, three kinds of mix proportions including river sand (HS), river sand + manufactured sand (HS+JZ), manufactured sand (JZ) were selected, the dry and wet cycle tests were conducted under two solutions of 7.5% (mass fraction) MgSO_4?and 15% (mass fraction) MgSO_4. By testing the mass loss rate, ultrasonic velocity, relative dynamic modulus of elasticity and compressive strength ratio, combined with the internal cracks and internal micro structure, comprehensive factors were analyzed. The results show that after 18 dry and wet cycles, the mass loss rates of three kinds of concrete in two kinds of 7.5%MgSO₄ and 15%MgSO₄ are increased respectively to 6.6%, 5.5%, 4.5% and 8.9%, 7.6%, 6.5%. The ultrasonic velocities[JP] decrease respectively to 3.600, 3.684, 3.800 km·s^-1?and 3.238, 3.368, 3.444 km·s^-1. The relative dynamic moduli of elasticity decrease respectively to 64%, 68%, 76% and 55%, 57%, 67%. The ratios of compressive strength decrease to 0.84, 0.83, 0.88 and 0.72, 0.75, 0.78 respectively. The main erosion products of river sand concrete is mainly white fibrous crystals ettringite. The main erosion products of basalt manufactured sand concrete is mainly white gypsum. As a result of a few stone powder and its own corrosion resistance in the basalt manufactured sand, it can effectively improve the ability of concrete to resist sulphate erosion.