Effects of superabsorbent polymer on interfacial transition zone and mechanical properties of ultra-high performance concrete

摘要

In this study, two particle sizes of superabsorbent polymer (SAP) with different contents (0-0.6%) were incorporated in the UHPC samples cured under two regimes: water and steam curing. The interfacial transition zone (ITZ) associated properties, namely compressive strength, flexural strength, and pullout behavior of steel fiber were evaluated. Micro-hardness method and backscattered electron (BSE) imaging examinations were also applied to investigate the underlying mechanisms of SAP performance in UHPC. The results show that the use of SAP densified the ITZ and reduced micro-cracks around the fibers. However, the pores left from SAP impaired the bonding strength and ITZ of UHPC, when high contents and large size of SAP particles were incorporated. Steam curing, though, partly compensated the bond strength loss of fibers caused by the SAP. (C) 2019 Elsevier Ltd. All rights reserved.