掺稻壳灰与纤维素纤维混凝土抗氯离子渗透和抗冻性试验研究OA北大核心CSTPCD

To study the influence of water-to-binder ratio,rice husk ash,and cellulose fiber on the durability performance of concrete,nine orthogonal tests were conducted with three variables:rice husk ash content(0,10%,and 20%),cellulose fiber content(0.7 kg/m3,1.1 kg/m3 and 1.6 kg/m3),and water-to-binder ratio(0.37,0.41 and 0.45).The impact of these factors on chloride ion penetration resistance and freeze-thaw resistance of concrete was analyzed,and prediction models for mass loss rate and relative dynamic elastic modulus of rice husk ash and fiber concrete during freezing and thawing were established,separately.The results show that the degree of impact of each factor on chloride ion penetration resistance and freeze-thaw resistance of concrete is as follows in descending order:water-to-binder ratio>rice husk ash content>cellulose fiber content.The chloride ion penetration resistance and freeze-thaw resistance of concrete are significantly enhanced with increasing rice husk ash content,while it shows a trend of first enhancing and then weakening with increasing cellulose fiber content.The optimum performance is achieved at a water-to-binder ratio of 0.37.When the rice husk ash content is 20%,the concrete has the best chloride ion penetration resistance and the optimal freeze-thaw resistance.When the cellulose fiber content is 1.1 kg/m3,the concrete exhibits the best chloride ion penetration resistance and the strongest freeze-thaw resistance.Increasing the dosage of rice husk ash,and adding a suitable amount of cellulose fibers can improve the density of the concrete matrix,reduce microcracks,and enhance the durability performance of the concrete.The prediction model for the mass loss rate and relative dynamic modulus of elasticity of rice husk ash fiber concrete established is in good agreement with experimental results,and has a certain applicability.This can provide a theoretical basis and support for the preparation of green high-performance concrete.