Experimental Study on Durability of Repair Materials for Expressway Concrete Guardrail
To solve the problem of erosion and damage of the expressway concrete guardrail caused by the snowmelt agent thrown in seasonal frozen areas,based on the conventional formula of repair mortar,four modifiers including high-molecular polymer,silica fume,pulverized fly ash,and water-repellent admixture were added,respectively.The orthogonal experiment was used to optimize the formula,and the compressive strength ratio and mass loss rate of the specimens before and after the experiment were used as the assessment indexes.The NaCl solution with a concentration of 4％was adopted and the number of the freeze-thaw cycle was 200 times.The study results showed that the addition of 1.0％high-molecular polymer of total mass of repair materials,7.0％silica fume and 5.0％pulverized fly ash of cement mass,and 0.7％water-repellent admixture of total mass of repair materials could significantly increase the salt scaling resistance.Compared with the specimens without freeze-thaw,the compressive strength decreased by 8.3％and the mass loss was 3.1％,which can effectively improve durability and reduce maintenance costs.
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