| There are many saline soils and salt lakes distributed along the roads and railways innorthwestern China,especially in Gansu and Xinjiang.In recent years,under the“Belt and Road”policy,the country has carried out a large number of western infrastructure projects andHuimin projects.Among them,the economic losses and casualties caused by the negligence of sulfate and other salts on the erosion of structures are common.Therefore,the study of sulfate on concrete erosion has significant practical significance.In this paper,according to the site environment of Baiming Expressway,the mortar resistance of cement mortar mixed with 4 kinds of ultra-fine micropowders was studied,and40?,20?,10?and 5?were selected as the erosion temperature in this test.0.5,0.42,0.34,and 0.26 are the cement-sand-water-to-binder ratios of this test,and the orthogonal test design is carried out based on various factors.After 28 days of standard curing of the cement mortar specimen in this test,the two erosion systems of full immersion and dry-wet cycle were used to test,and the sulfate erosion resistance of the cement mortar was studied from the following directions:1.By observing the appearance characteristics of specimens of various ages,test the flexural strength and compressive strength of specimens of various ages,calculate the flexural corrosion resistance coefficient and compressive corrosion resistance coefficient of specimens of various ages,comprehensive analysis and evaluate the resistance of cement mortar to sulfate attack.2.Orthogonal test method was used to study the optimal level combination of temperature,fineness of fine powder,amount of fine powder,water-binder ratio to sulfate resistance of cement mortar..3.Study the influence of various erosion factors on the mortar of cement mortar after erosion.4.Based on the obtained test data,an artificial neural network model for predicting the resistance of cement mortar to sulfate attack was established.By testing the macro indexes of cement mortar specimens of different erosion ages under the full immersion and dry-wet cycle erosion system,and comparing and analyzing the change rules of each index,the research shows that:1.Under the conditions of full immersion conditions and dry-wet cycle conditions,the specimens have the best development in the immersion environment of 40?under the condition that the water-binder ratio and the amount of fine powder are unchanged..2.Under the condition of full immersion,when the fineness of the fine powder does not change,the anti-corrosion resistance coefficient and compressive corrosion resistance coefficient of the test specimens of each group are 30%in the fine powder,and the water-binder ratio is 0.34.The anti-erosion ability is the best,so the influence of temperature,micro-powder content and water-binder ratio on the anti-erosion ability of the test piece is obviously more significant.3.The factors affecting the resistance to sulfate corrosion of cement mortar under full immersion conditions are D factor(water-binder ratio),A factor(fine powder content),B factor(temperature),and C factor(fine powder fineness);The factors that affect the resistance of the cement mortar to sulfate corrosion under dry and wet cycling conditions are D factor(water-binder ratio),B factor(temperature),A factor(fine powder content),and C factor(fine powder fineness);4.The 4 factors and 4 levels that affect the erosion of the cement mortar in the sulfate erosion test obtained under full immersion are best combined as A3B2C1D3,that is,the amount of fine powder is 30%,the temperature is 40?,the fineness of fine powder is 400 m~2/Kg,water Glue ratio 0.34.5.The 4 factors and 4 levels that affect the erosion of the cement mortar in the sulfate resistance test obtained under the dry and wet cycle conditions are best combined as A4B4C1D2,that is,the amount of fine powder is 5%,the temperature is 40?,the fineness of fine powder is 400 m~2/Kg,water Glue ratio 0.26. |
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