Effect Of Loading On Permeability Of Rccycled Aggregate Concrete

This thesis presents an experimental study on permeability of recycled concrete under and after loading. Permeability of concrete after loading at various stress levels, including recycled concrete and normal concrete (at water binder ratios of 0.586 and 0.250), is measured by means of the Germanns water permeability test method and the chloride ion penetration test method. Furthermore, Permeability of concretes mentioned above under loading at various stress levels is evaluated by means of the depth of Chloride permeability test method. The goal of this thesis is to study the effect of loading on permeability of recycled concrete subjected to loading.The experimental results of concrete after loading indicate that, for a few types of concrete, i.e., recycled concrete at a water binder ratio of 0.586 and 50% replacement of recycled coarse aggregate, water permeability of recycled concrete was influenced by loading at a certain stress known as the critical stress. When the compressive stress is lower than that, the effect of loading on the water permeability in concretes is not significant; when the compressive stress exceeds the critical stress, the influence of loading on the water permeability in concretes can be observed noticeably. Water permeability of Recycled concrete which is at a water binder ratio of 0.586 and 100% replacement of recycled coarse aggregate was influenced by loading with no critical-stress observed in test and presented a linear growth with the increasing stress-strength, the results are the same as that of the recycled concrete which is at a water binder ratio of 0.250 and with the 50% and 100% replacement of recycled coarse aggregate respectively. At the same water binder ratios of 0.586 and 0.250, chloride ion charge passed of recycled concrete was higher than that of normal concrete. Moreover, chloride ion charge passed of recycled concrete was increased with the incremental replacement of recycled coarse aggregate.The experimental results of the concrete under loading indicate that, under the two conditions of the same water binder ratios of 0.586 and 0.250 and the same stress-strength ratio of 0.65 and 0.75 under the 90 min loading of duration, the depth of chloride permeability of recycled concrete is higher than that of normal concrete, After loading of duration, water permeability coefficient and chloride ion charge-passed presented the similar results. The data (depth of Chloride permeability) of the depth of Chloride permeability test under loading can't be correlated with those water permeability coefficient after loading for the data are limited, so it is difficult to judge them correlation.