Title: Effects of Temperature and Stress on Creep Behavior of PP and Hybrid Fiber Reinforced Reactive Powder Concrete
Author(s): Xiaomeng Hou , Muhammad Abid, Wenzhong Zheng and Raja Rizwan Hussain
Appears on pages(s):
Keywords: reactive powder concrete (RPC), PP ﬁber, hybrid ﬁber, short-term creep (STC), transient strain (TS), ﬁre safety design
Reactive powder concrete (RPC) is an advanced cementitious material with ultra-high strength, remarkable durabil-ity and excellent toughness. However, temperature dependent creep is a major concern as very little work has been reported in the literature. Therefore, systematic investigations are still missing in state of the art. This paper focuses on the impact of Polypropylene (PP) and hybrid (steel and PP) ﬁbers on creep behavior of RPC at elevated tempera-ture. Temperature-dependent creep is further characterized into free thermal strain (FTS), short-term creep (STC) and transient strain (TS), based on diﬀerent thermo-mechanical regimes. Varying heating and loading schemes were considered such as steady-state and transient thermo-mechanical conditions. The target temperatures considered for steady-state thermal conditions and transient case are 120, 300, 500, 700 and 900 °C. Compressive strength was considered up to 60% load ratio of ambient and temperature dependency. The result shows that STC increases with increasing stress level and higher target temperature. The increase in STC becomes obvious above the transition stage of quartz aggregate. Furthermore, HRPC have signiﬁcantly higher STC than PRPC and other traditional types of concretes. The evolution of FTS and TS was quite slow below 250 °C. However, at high temperature signiﬁcant increase in FTS and TS were observed. Furthermore, increasing stress level and the addition of steel ﬁbers results in high TS. Overall, the performance of PP ﬁber was better than the hybrid ﬁbers on the creep behaviour of RPC. Finally, constitutive relationships were proposed for FTS, STC and TS, which will be used as input data in numerical models of ﬁre resistance calculations.