Study On The Waterproofing And Anti-Erosion Effect Of Chloride Ion For Integral Water Repellent Concrete

Many concrete structures can not reach their designed service life because of their poor durability. Water and aggressive substances such as chloride ions is the main prerequisite in the deterioration of concrete. In aggressive environment, water repellent treatment is an effective path to delay the repair and improve the durability of concrete. Integral water repellent treatment not only is accounted a suitable measure to improve the durability of concrete structures exposed to chlorides, but also may eventually open the possibility to design more durable structures in the future.The main aims of this project are to investigate the water absorption of concrete waterproofing and resistance to chloride ion penetration performance, and to predict the life of concrete structures. Four types of concrete have been prepared with three silane emulsion and four kinds of metal soap. Three different water-cement ratios of concrete ranging from 0.4 to 0.6 have been selected. In the fourth type of concrete 20 % of Portland cement has been replaced by fly ash (FA). In this case the water-binder ratio is 0.5. Compressive strength, water repellence, prevention of chloride penetration and water repellent distribution of cement-based material with silane emulsion and metal soaps are tested respectively. In this paper, the effect of water repellent dosage is compared, which is expected to analysis the influence of addition of water repellent to fresh concrete on property and durability of cement-based materials.It turned out that the reduction of the absorption of moisture and concrete penetration of harmful media is effectively influenced by addition of silane emulsion and metal soaps. At the same time, the degree of hydration of cement-based materials is reduced, so that the compressive strength of concrete is decreased. Tests of capillary water absorption of treated and untreated concrete are carried out and result shows that water absorption coefficient of treated concrete is about 25% of untreated concrete. But the addition of fly ash to concrete only has a modest effect on capillary suction of water. Mixed with waterproofing agent, the concrete which were weared from the surface to the depth of 5mm, 15mm and 25mm presented a higher water absorption than no wear concrete. By means of chloride ingress of treated concrete, it can be concluded that a limited range of depth is gathered from the surface and an effective chloride barrier can be established by water repellent treatment. Integral water repellent treatment has obviously improved the durability of cement-based materials. To predict the life of concrete structure in chloride ion environment, the service life of untreated concrete is more than twice time as long as the untreated.