Study On Effect Of Controlled Permeable Formwork To The Concrete With Ground Slag

With the application of concrete structures more and more widely, the problem of durability of concrete has also been studied extensively and continuously in civil engineering field. The use of active mineral admixture improves the performance of concrete, at the same time, also reduces the energy consumption and protects the environment. Controlled permeable formwork is also one kind of technique to improve the durability of concrete structures. Many scholars on the performance of concrete mixed with ground slag and controlled permeable formwork alone under the action of improving do a lot of researches, but the research of controlled permeable formwork’s effect on concrete with ground slag is few, the application of controlled permeable formwork is limited.The article researches how the controlled permeable formwork improve the mechanism of the concrete with ground slag mainly from two aspects: one is to study after using controlled permeable formwork, concrete with ground slag or without ground slag surface movement of cementitious materials accumulated particulate cementitious materials and particle size distribution, quantitative analysis from the concrete surface at different depth hydration; Another one is to study the influence of the durability of concrete mixed with ground slag or without ground slag. In this topic,the following five tests are carried out on the test block of two proportioning, two kinds of templates : Determination of Ca(OH)2 in the test, Saturated water absorption test of concrete, The strength of concrete rebound test, Concrete capillary water absorption test, Concrete freeze-thaw cycling test.The results showed that: one, controlled permeable formwork can promote the concrete with ground slag surface cement hydration, the standard and natural curing conditions improve three point five percentage and four percentage respectively,and influence depth is larger, the influence depth of ordinary template is generally about ten millimeter, and the influence depth of controlled permeable formwork for the cement hydration is about twenty millimeter.;two, controlled permeable formwork increases the durability of concrete mixed with ground slag in significantly. The natural and standard curing conditions improve six percentage and thirteen point two percentage respectively at the aspect of compressive strength, c+k-pmf-1 liken to c+k-pmf-0. The natural and standard curing conditions improve twenty-eight point two percentage and thirty-three point nine percentage respectively at the aspect of porosity, c+k-pmf-1 liken to c+k-pmf-0. The natural and standard curing conditions improve nine point three percentage and fifty point two percentage respectively at the aspect of the capillary water quantity of the surface, c+k-pmf-1 liken to c+k-pmf-0. The natural and standard curing conditions improve four point five percentage and three point five percentage respectively at the aspect of the capillary water quantity of the core-structure, c+k-pmf-1 liken to c+k-pmf-0. After the same freeze-thaw cycles,weightlessness rate reduced and the relative dynamic elastic modulus increased, c+k-pmf-1 liken to c+k-pmf-0.