Design And Characterization On Permeable Crystalline Concrete Waterproofing Agent

With the continuous development of urbanization,concrete buildings are increasing day by day.As a rigid and porous material,concrete often has leakage problems during the design life.Frequent maintenance will incur high maintenance costs.Cementitious capillary crystalline waterproofing agent can effectively solve this problem.At present,this mature technology is mastered by developed countries such as the United States,Japan,and Canada,and it is kept secret.The core masterbatch of cement-based permeable crystalline waterproofing agent is a key technology.For a long time,domestic enterprises have relied on imported active substances,reprocessed,and affixed new labels to sale in the market,with uneven quality.This subject aims to design a permeable crystalline concrete waterproofing agent with independent intellectual property rights and reliable performance,and to analyze its mechanism.By analyzing the cement hydration process and the mechanism of permeation crystallization,and comparing the performance of the active chemical substances in the waterproofing agent,the possible range of core components is proposed.Through leak-stop test and mechanical performance test,four basic active components of waterproofing agent are determined: active silicon waterproofing aid MC(sodium methyl silicate: sodium metaaluminate=3:1);amino carboxylic acid complex AG(Glycine: Calcium Lignosulfonate=2.5:1);Waterproof additive LN(metakaolin: sodium sulfate=1:1);Calcium ion adjuvant PL(slaked lime).Through single factor analysis of each active component to determine the type of influence on the performance of cement mortar and the range of content.After orthogonal optimization,the final mixture ratio of IOC waterproofing agent is determined,MC: AG: PL: LN: Cement: Quartz Sand = 5: 2: 2: 2: 2: 3: 2.Named as IOC water repellent,the basic performance test on it has reached national standards.Compare the self-made IOC waterproofing agent,the Canadian Kayton KIM waterproofing agent and the domestic brand LLH waterproofing agent,compare the performance of the three,and objectively evaluate the effect of the IOC waterproofing agent on the performance of concrete.The test results show that:(1)The compressive strength of the test group with IOC waterproofing agent is increased by 4.8%,the flexural strength is increased by 4.4%,and the water absorption rate is higher than the blank group.The blank group decreased by 43.6%.The active substances in IOC can improve the density of the structure and improve its mechanical properties.(2)In the durability study,after adding IOC waterproofing agent to the concrete,the resistance to chemical erosion was significantly improved,and the strength loss rate in the acid solution was 2.7%,which was 19.8% lower than that of the blank group.The anti-chloride ion penetration effect of IOC waterproofing agent on concrete is also significantly improved,with an average electric flux of 739.09 C,which is 17.1% lower than the blank group.(3)IOC waterproofing agent can significantly improve the self-healing ability of cement paste.For the 28 d cement paste,the maximum self-healing width of the blank group is 0.18 mm,and it takes 9d to completely repair;the IOC waterproofing agent group can self-heal up to 0.36 mm cracks,which takes 7d.Under the same crack width,The shorter the hydration time of the cement specimen,the stronger the self-healing ability.Comprehensive comparison of IOC,KIM and LLH waterproofing agents,IOC waterproofing agent performance is significantly better than LLH waterproofing agent,slightly inferior to KIM waterproofing agent.Through SEM and XRD microscopic tests,the results show that in the concrete mixed with IOC waterproofing agent,more calcium silicate hydrate is gelled,flocculent and reticulated overlapping,and more needle-like shapes ettringite crystals can be found,the calcium hydroxide produced by cement hydration is more uniformity,and the crystal diameter is reduced.The chemical components in the IOC waterproofing agent interact with each other to improve the waterproof and impermeable properties of concrete.