Research On The Effect Of The Different Curing Conditions On The Pore Structure And The Resistance To Permeability Of Concrete

As the development of concrete technology, its durability is gradually paid attention to,as an important index to measure the durability of concrete, impermeability is paid more and more attention by people. Impermeability is determined by the internal structure of concrete,and the development of the internal structure is affected by various external factors. The properties and internal structure of concrete has been studied by many scholars at room temperature, but the study of concrete cured at negative temperature condition is less.This article first has taken the concrete without adding mineral admixture as the research object, pore structure and impermeability of different water to binder ratio of the concrete cured at-3 ℃ condition and standard curing condition were studied by DC method, RCM method, MIP method and stomatal analysis method in the experiments. By contrast, found out the difference between two kinds of concrete, and got the change rules of impermeability and pore structure with the change of water to binder ratio. On the basis of the experimental data of mercury injection test, calculated the fractal dimension, then contacted it with the impermeability and pore structure of concrete, found out the related curve and change trend,verified the conclusions of the fractal theory has been used in the field of concrete. The result showed that, the pore structure deteriorated, the compressive strength became smaller and the impermeability became weaker with the increase of fractal dimension. And then carried on a further argument for the relationship of compressive strength and impermeability of concrete, the results show that: they have great differences between the concrete cured at negative temperature and the concrete with equal compressive strength cured at standard curing condition for the impermeability and pore structure.Secondly, this article first has taken the concrete with adding mineral admixture as the research object, pore structure and impermeability of concrete cured at different curing temperature and humidity were studied. The results show that: when the curing condition changed, the change rules of impermeability and pore structure with the change of water to binder ratio also changed, the curing humidity of concrete have a great influence on its impermeability, and when the curing temperature changed, the influence of mineral admixture on the properties and internal structure of concrete also changed seriously. When the curing temperature is negative temperature, adding mineral admixture will weaken the impermeability of concrete.