Research On Influencing Factors Of Carbonation Of High-flowing Concrete With Admixture

Modern buildings with reinforced concrete as the main structural material, caused damage of reinforced concrete structure reinforcement corrosion is the first factor, is the main factor causing corrosion of concrete carbonation and durability of concrete with the main index. Cement mixing material increase in dosage, percentage of admixture in concrete and the increasing CO2 concentration in the air, accelerated carbonation of reinforced concrete structures. Concrete carbonation has led to the premature failure of the project, brought some economic loss to society.Therefore, based on orthogonal tests and admixture Mono test on influence factors of admixture for high-flowing concrete carbonization research aims to improve the carbonation resistance of concrete and reasonable evaluation of admixture for high-flowing concrete carbonation resistance theory is important for reduced maintenance costs and extend its service life.This percentage of admixture, water-binder ratio, mixed of fly ash and powder slag and two kinds of curing style as factors, and accelerated carbonation depth of concrete compressive strength index, established the five-factors and five-levels orthogonal testing programme. On this basis, a common admixture and fly ash and powder slag, formulated admixture Mono test programme. Under the existing concrete mix design procedures to determine high-flowing concrete mix. Different levels according to the current test method standards measured combinations accelerated carbonation depth of concrete and compressive strength, and the experimental results were analyzed, the results show that:(1) Influencing factors liquid admixtures accelerated Carbonation depth of concrete by significant order from high to low is: Percentage of admixture, Water-binder ratio, Curing style, Mixed of fly ash and powder slag. Admixture quantity the most significant effect on accelerated carbonation of high-flowing concrete to control percentage of admixture on carbonation resistance of concrete more effectively. Accelerated carbonation of high-flowing concrete with the percentage of admixture and increase of water-Binder ratio increased; as the curing time and the increase in the proportion of powder slag accelerated carbonation depth of concrete on the whole lower standard curing 56 d, accelerated carbonation depth of concrete is relatively stable, concrete mixed with large amount admixtures for standard curing 56 d of accelerated carbonation depths were evaluated.(2) Liquid admixture influencing factors of compressive strength of concrete by a significant order from high to low is: Curing style, Water-binder ratio, mixed of fly ash and powder slag, Percentage of admixture. Influence of water-Binder ratio on high-flowing concrete compressive strength significantly strength determines the size of water cement ratio of the concrete. Increase in compressive strength of high-flowing concrete with curing time, water-Binder ratio and percentage of admixture to reduce the overall increase, along with the increase in the proportion of powder slag first increasing and then decreasing law of development.(3) The admixture for high-flowing concrete compressive strength of standard curing 28 d and 28 d accelerated carbonation depth of relationship with their counterparts are: powder slag mixed with fly ash concrete with a high linear correlation; close to the high degree of linear dependence of fly ash concrete; powder slag is not relevant.