Structural behaviour of lightweight concrete strengthened with engineered cementitious composites

Batran, Tayseer Zakaria Mahmoud Mohamed (2022) Structural behaviour of lightweight concrete strengthened with engineered cementitious composites. Masters thesis, Memorial University of Newfoundland.

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Abstract

This thesis evaluated the feasibility of using engineered cementitious composite (ECC), to strengthen lightweight concrete (LWC) against various mechanical loads. Three experimental studies have been conducted on both plain small-scale and reinforced large-scale concrete specimens to accomplish the research objective. The first and second studies investigated the use of ECC to strengthen either the tension or compression zone of large-scale reinforced LWC beams tested in flexure and shear. The third study focused on the use of ECC in strengthening small-scale unreinforced beams and cylindrical specimens tested under drop-weight impact loads. The results of the first and second studies indicated that using ECC developed with polyvinyl alcohol fibers or steel fibers (ECCP or ECCS, respectively) is an effective technique to improve the flexural and shear behaviour of LWC beams with no significant increase in their self-weight. In both studies, strengthening the compression zone yielded higher ductility and energy absorption capacity. Meanwhile, better cracking control was observed when the tension zone was strengthened, thus assuring a better durability for structural members. In flexure, the highest improvement in the load-carrying capacity was obtained when the LWC beams strengthened at the tension zone, whereas strengthening the compression zone was more effective in improving the shear capacity. The results of the third study indicated that either ECCP or ECCS could achieve a good bonding with LWC substrate. The use of ECC along with LWC also offers novel hybrid composites with low-density and improved impact resistance, thus providing promising composites for strengthening lightweight structures exposed to high impact loading.

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