Experimental Study On Improvement Of New Composite Waterproofing Agent Based On Concrete Properties

The waterproof and impermeability of concrete is closely related to the durability of concrete.As a concrete chemical admixture,waterproofing agent can effectively improve the waterproof and impermeability of concrete,thereby improving the durability of concrete.Based on the properties of concrete,this paper optimizes the design of the self-made waterproofing agent by changing the dosage,compounding the waterproofing agent,and introducing new components,and obtains the optimal ratio of the new composite waterproofing agent.The main research conclusions are as follows:(1)The change law of concrete mixture properties,mechanical properties,waterproof and impermeability properties and shrinkage properties before and after the improvement of the waterproofing agent was studied and analyzed.The test results show that the self-made waterproofing agent has limited effect on concrete when it is mixed alone,and the change of the dosage cannot effectively improve the performance of concrete.After the waterproofing agent is compounded and improved,the penetration height ratio of the tested concrete reaches 33%,the 28d compressive strength ratio reaches 105%,and other performance indicators meet the relevant technical requirements of "Waterproofing Agent for Mortar and Concrete"(JC 474-2008).(2)The effect of self-made waterproofing agent on the microstructure and hydration products of concrete was studied and analyzed.The test results show that inorganic waterproofing agent can generate a large amount of acicular ettringite in concrete,organic waterproofing agent can optimize the transition zone of concrete interface,lithium silicate can improve the compactness of concrete,and the combined action of multiple components improves the microstructure of concrete after composite improvement.(3)The effect of self-made waterproofing agent on the frost resistance of concrete was studied and analyzed.The test results show that single addition of inorganic waterproofing agent will reduce the frost resistance of concrete,and single addition of organic waterproofing agent will significantly improve the frost resistance of concrete.After the composite improvement of waterproofing agent,due to the existence of inorganic waterproofing agent,the frost resistance of concrete is slightly lower than that of concrete mixed with organic waterproofing agent alone,but its relative dynamic elastic modulus can still maintain a high level after 300 freeze-thaw cycles.The improvement of concrete waterproofing agent through multi-component compounding can make the waterproofing agent have a positive impact on other performances on the basis of improving the waterproof and impermeability of concrete.The research results have certain practical significance for solving the problem of water leakage in practical engineering.The use of microscopic testing methods to explore the action mechanism of composite waterproofing agents has certain reference value for guiding the development of new waterproofing materials.