Issue 46

Y. Yanya, Frattura ed Integrità Strutturale, 46 (2018) 343-351; DOI: 10.3221/IGF-ESIS.46.31 349 Porosity/% 14 15 16 17 18 19 21 20 0 2 4 6 8 10 Compressive strength/MPA RC100D RC30 RC50 RC0 RC100 Figure 6 : The diagram of the relationship between the porosity of the pervious concrete and compressive strength. The relationship between the compressive strength and splitting tensile strength of the pervious concrete is shown in Fig. 7. The results demonstrated that the splitting tensile strength improved with the increase of the compressive strength. 513 .01 ) ( 265 .0 c st f f  748 .0 2  R Figure 7 : Compressive strength and splitting tensile strength C ONCLUSIONS he recycled aggregate was obtained by mechanically crushing and artificially screening the waste prefabricated concrete components in this study, and moreover it was tested and analyzed to explore the effects of the mixing amount of recycled aggregate on the strength and permeability performance of pervious concrete. The main conclusions are as follows. The water absorption of the recycled coarse aggregate was 13 times that of the natural aggregate, and its 10-min water absorption could be 90% of the recycled coarse aggregate in the saturated water absorption state. The apparent and stacking density of the recycled coarse aggregate was 95.5% and 81.2% that of the natural aggregate and the crushing value of the former was 2 times that of the latter. Considering the high water absorption of the recycled coarse aggregate, added water whose amount was equal to the 10- min water absorption of the recycled coarse aggregate was used to avoid region with low water cement ratio. The strength and water permeability of the recycled pervious concrete satisfied the regulations. The test results were superior to the pervious concrete prepared using natural aggregate in the same proportion. Therefore it is feasible to prepare pervious concrete using recycled aggregate in the aspect of performance. The blending ratio of the recycled coarse aggregate was in no obvious relation with the porosity changes of the pervious concrete. The porosity was the largest when the replacement rate was 100%, but the permeability coefficient increased with the porosity. Moreover the addition of double grain grade aggregate improved the compressive strength of the recycled pervious concrete and decreased the porosity and water permeability. T