Study On Application Of Limestone Powder In Waterproof Mortar

Cement-based waterproof material belongs to the category of building sealing materials and rigid waterproof and plugging materials.It has the advantages that other materials do not have,that is,it can be constructed on the wet base surface,can not afford to drum after construction,and can be cured on the wet environment and waterproof on the back.In this paper,the best proportion of waterproof mortar is obtained by studying the influence law and working principle of admixtures of different kinds and amounts of silicone hydrophobic agent,redispersible latex powder,polypropylene fiber,expansion agent and other admixtures on the working performance,mechanical performance and impermeability of waterproof mortar.Limestone powder is produced in the process of crushing limestone stone slag powder particle size is less than 0.075 mm,because its resources are widely distributed,simple processing production,is currently widely used in cement mortar,concrete raw materials and the lime stone powder used in waterproof mortar,can not only alleviate the fly ash and other mineral admixtures resource shortage problem of effective use of existing resources,development of construction industry Moreover,it can further improve the work,mechanics,durability and other properties of waterproof mortar.In this paper,different fineness and dosage of limestone powder are mixed into the optimal mix ratio of waterproof mortar to study its influence law on the work,mechanics and durability of waterproof mortar.Combined with microscopic analysis,the working principle of limestone powder on waterproof mortar is understood.The main conclusions are as follows:(1)mixed with silicone hydrophobic agent test results show that: appropriate amount of two kinds of silicone hydrophobic agent(ZS-Ⅰ and ZS-Ner)can significantly improve the performance of waterproof mortar,when ZS-Si and ZS-Nat content in 5%,0.54% respectively,waterproof mortar impermeability strength reached the maximum 1.8MPa.(2)The test results of adding redispersible latex powder show that the waterproof performance of waterproof mortar can be significantly improved before the content of1.8%.When the content of 1.8% is added,the impermeability strength reaches 1.6MPa,and the impermeability strength decreases with the continuous increase of the content.At the same time,the redispersible latex powder can effectively improve the performance of waterproof mortar,but it will significantly reduce the strength of mortar.When the content of the redispersible latex powder is 2.5%,the 28 d strength of waterproof mortar decreases by 31.3%.(3)The test results of adding polypropylene fiber show that the waterproof performance of waterproof mortar can be improved by the appropriate amount of fiber,and the anti-permeability strength reaches the peak value of 1.4MPa when the content is1.25%.With the increase of fiber content,the water retention rate of mortar continues to increase,and the maximum water retention rate reaches 96% when the fiber content reaches 1.6%.The mortar strength can be increased with appropriate fiber content,and the maximum strength reaches 17.4 MPa when the fiber content is 1.25%.(4)The test results of adding two kinds of expansion agents(PZ-Ⅰ,PZ-Ⅱ)show that: when the content of PZ-Ⅱis 7.14%,the impermeability of waterproof mortar can be significantly improved,and the impermeability strength reaches the peak of 1.1MPa,and the working performance and strength can be improved and increased.When the content of PZ-Ⅱ is 0.2%,the impermeability strength of waterproof mortar reaches the maximum 1.5MPa,and the water retention rate increases to 96.6%,and the compressive strength increases by 22% compared with the benchmark specimen.(5)The test results of adding three particle sizes of limestone powder(400 mesh,800 mesh,1250 mesh)show that: with the increase of the particle size of limestone powder,the water absorption rate of waterproof mortar gradually increases,and the anti-permeability ability gradually decreases.The anti-permeability ability is the best when the equal amount of 400 mesh limestone powder is added to replace cement at10%.At the same time,when the content of 800-mesh limestone powder is 10%,the strength improvement effect of 28 d is the best.However,when the content of1250-mesh limestone powder is added,the compression-folding ratio of waterproof mortar is the smallest,and the material flexibility is also the best.According to the test results,when cement,sand(river sand: Sand machine =3:7),water,silicone hydrophobic agent ZS-Ⅱ,redispersible latex powder,polypropylene fiber,expansion agent PZ-N mixing amount is 280kg/m3,1400kg/m3,200kg/m3,0.54%,1.8%,1.25%,0.2%,get the best proportion of waterproof mortar.When the dosage of 400 mesh limestone powder was 10%,the water absorption rate and anti-permeability ability were improved the best.When the content of 800 mesh limestone powder is 10%,the strength improvement effect is the best.When the content of 1250 mesh limestone powder is 15%,the working performance can be improved best.