| Alkali activated slag concrete is an environmentally friendly material that can effectively utilize industrial waste residue and reduce environmental pollution.However,due to the short setting time,the application of alkali-activated slag has been greatly restricted.In this paper,for the purpose of promoting the application of alkali-activated concrete,a new strategy of has been carried out from the characteristics of alkali-activated slag concrete rapid setting.Moreover,the alkali-activated slag concrete is also applied on the road repairing material.On the one hand,this paper proposes a new type of retarding method.Part of the alkali activator,the anhydrous sodium silicate is processed through the capsule shell or the capsule,so that the part of the alkali activating agent is slowly released to promote hydration to achieve setting retard effect.In order to verify the effectiveness of the method and the law of its influence on the properties of the material,the following studies were carried out.(1)Setting 5 experimental groups with the treatment method and treatment ratio of alkali activator as variables,and conclude the conclusion by testing the setting time of15 test pieces: the proposed retarding method has obvious retarding effect and can make the initial setting time Adjust within 60min-196 min.(2)It is concluded that the compression and flexural strength of 75 specimens at different ages are tested: the retarding method has little effect on the mechanical properties of the material;the shrinkage,carbonization,and chlorine ion penetration resistance experiments on 45 specimens The analysis of the results shows that the anhydrous sodium silicate can be slowly released after the treatment method proposed in this article,so that the density of the material gradually increases,and the anti-carbonization ability and anti-chloride ion penetration ability of the material are improved to a certain extent.At the same time,due to the retardation method's reaction to reduce the heat of hydration and the internal curing effect of the treatment of alkali activator,the shrinkage of the material is reduced;through the self-healing experiment results of 8 specimens,it is found that Sustained release promotes hydration and its own dissolution characteristics.It can play a certain effect of self-repairing when cracks are mixed into the slurry to prepare test pieces.On the other hand,there are a large amounts of cement concrete pavement damages in China every year,and the characteristics of alkali-activated concrete quick setting and early strength are consistent with the requirements for rapid pavement repair materials.For the special application of alkali-excited concrete to pavement repair,the following analysis were mainly carried out.(1)In order to meet the strength index of 8h open traffic,with the alkali excitation concentration as a variable,the 8h compressive and flexural strengths of 18 specimens were measured,and the benchmark mix ratio and alkali excitation concentration of this study were determined.(2)In order to analyze the applicability of alkali-excited recycled concrete for pavement repair,the replacement rate of recycled fine aggregate is variable and a comparison group of ordinary cement concrete with the same ratio is set.Incorporating recycled fine aggregate can improve the early mechanical properties of alkali-excited concrete,and can be applied to pavement repairs to achieve the effect of opening traffic earlier;through the experimental analysis of the durability of 36 specimens,the long-term comprehensive durability of alkali-excited concrete will The replacement rate of recycled fine aggregate increases and decreases,but they are better than ordinary cement concrete.(3)Taking the addition of emulsified oil as a variable,through the shrinkage test of 39 test pieces and the 8h flexural strength test,it was found that emulsified oil can achieve a good shrinkage effect and does not affect the goal of open traffic in 8h. |
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