عنوان مقاله [English]
A suitable application for recycled concrete aggregate (RCA) is in concrete pavements. In this regards, one of the main concerns is related to the deicer-salt scaling resistance of concrete containing both coarse and fine recycled concrete aggregates (CRCA and FRCA). In this study, two groups of concrete specimens were prepared: (a) mixes containing just CRCA, and (b) mixes containing both CRCA and FRCA. In the first group, coarse natural aggregate was replaced with CRCA at 30% and 50% levels. In the second group, 20% and 40% replacement of natural sand with FRCA was considered in mixes containing 30% and 50% CRCA. The mechanical properties and durability of concrete mixes were examined. Specifically, deicer-salt scaling resistance tests were carried out according to ASTM C 672 and MTO LS-412 R17. All the results showed inferior quality of concrete containing both CRCA and FRCA with respect to concrete containing just CRCA. Similar results were obtained for mixes containing CRCA compared to the reference mix. The findings indicated that the type of solution used for evaluating the deicer salt scaling resistance of concrete samples had no significant impact on the results. However, the results were generally influenced by the size of samples used in the tests as the results obtained from MTO LS412 were more accurate compared to those of ASTM C 672. In fact, it can be concluded that bigger samples seem to report more realistic results, i.e. results that are more in accordance with real conditions. Overall, if concrete is supposed to be used in regions with cold climate where deterioration of concrete due to frost action or deicer salt scaling is of concern, use of concrete made with recycled concrete aggregate is not recommended. This concern becomes more substantial if both fine recycled concrete aggregate and coarse recycled concrete aggregate is considered to be used in concrete pavements.