Influence of fluidity on mechanical and permeation performances of recycled aggregate mortar

Abstract

Abstract The use of recycled fine aggregates in making mortar is an effective measure to increase the social and ecological values these days due to the pressing issues associated with the over-exploitation of natural sand as well as disposal of construction and demolition wastes. To counteract the synergetic effects of W/C ratio, recycled fine aggregates quality and its content, fluidity was considered as parameter to formulate the recycled aggregate mortar. The experimental results of this investigation elucidate the effectiveness of fluidity on mechanical and permeation performances of recycled aggregate mortar. A comparison with the outcomes of conventional mortar is also presented. The experimental outcomes reveal that, recycled aggregate mortar requires additional amount of water to attain the same fluidity of controlled mortar due to inferior characteristics of RFA, such as high initial water absorption and volume of voids with in mortar. The setting characteristics of recycled aggregate mortar were influenced by the fluidity, recycled fine aggregates quality and its content and their setting times were earlier than that of controlled mortar. However, recycled aggregate mortar corresponding to the fluidity of 110 ± 2.5 mm and 160 ± 2.5 mm attained lower strength characteristics, lower pulse velocity value, higher permeable void content, higher water absorption by immersion and higher sorptivity than those associated to the fluidity of 135 ± 2.5 mm. Therefore, recycled aggregate mortar associated to the moderate fluidity of 135 ± 2.5 mm is feasible and exhibits better mechanical and permeation performances.