Research On Salt-frost Resistance And Impermeability Of Roller Compacted Rubberized Concrete

Rubberized concrete is a new technology on building dams in the past 30 years and receives more and more widely concern. It uses large transports and roller compaction machines to compact dry concrete in the large thin layer of rubberized concrete casting method, which has speed small investment and high economic efficiency and best suitable to be used in the construction of pavements and runways. However rubberized concrete is limited in some important projects because of rubberized concrete not meeting the high requirements of crack resistance. My professor Kang Jingfu put forward the concept of RCC according to the former study results. If the toughness of RCC may be improved by adding a portion of rubber particles, that will be very meaningful for theory research and project practice.The paper is a part of the subject called Properties of Roller Compacted Concrete supported by the National Natural Science Foundation. The purpose of the paper is to find out salt-frost resistance and the impermeability of roller compacted rubberized concrete (RCR) by replacing a portion of sand with the same volume of rubber powders , salt-frost resistance and the impermeability of RCR were experimentally studied using the same water-cement ratio and diffent volume of rubber particles.Finally,we can investigate the impermeability and salt-frost resistance of roller compacted rubberized concrete (RCR) by using diffent volume of rubber particles.Depending on test results, we may draw the following conclusions:(1) The compressive strength of RCR decreased linearly to the rubber content;(2) The reference concrete shows obviously a phenomenon of brittle fracture crack in compression process. In contrast, RCR formed the first cracks at edge of the specimena and then developed along the vertical edge when the specimen was in compression, and finally formed a number of small vertical cracks when it reached the ultimate load, which shows that RCR presents certain plastic.(3) Salt-frost resistance of RCR reduces with the amount of rubber. With the increase of rubber content, the amount of surface erosion of RCR will become more and more severe, which indicates that the incorporation of rubber powder makes salt-frost resistance of RCR deteriorate, compared with the reference concrete.(4) Because of the big admixture of rubber power in this experiment, test methods are different from that of the conventional concrete permeability experiment, and if not be fully dry, but just surface is dry, we will find splitting surface completely dark and can't see water marks after specimens are split. Therefore, in the rubber concrete permeability test we shall make specimens fully dry at first and then test.