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The aim of this research is to study the effect of different curing regimes on shrinkage and strength properties of self-consolidating mortars (SCM) containing silica fume in different contents. Self-consolidating mortars, as new technology products, are especially preferred for use in architectural elements and the rehabilitation and repair of reinforced concrete structures. SCM can be used in precast architectural elements or cast in place repair of reinforced concrete structures. Therefore, investigation on the effects of different curing methods on key properties of SCMs can be beneficial. The shrinkage and strength properties of SCMs produced at different replacement ratios of silica fume (SF) with cement in different curing regimes were studied, at this paper. SCM mixes were prepared in constant water/powder ratio and cured in four different regimes including water curing (WC), accelerated water curing (AWC), air curing (AC) and aluminum tape sealing (AS). A polycarboxylate-based superplasticizer (SP) was added to the mixtures at different rates by mass of the cementitious materials to have appropriate flowability. Fresh mortars workability was determined using mini slump flow and mini V-funnel tests. All SCM specimens were tested and evaluated for compressive strength, flexural strength and shrinkage. It has been found that different curing regimes have considerable effects on both shrinkage and strength properties of SCM. It can be concluded that aluminum tape sealing and accelerated water curing can be used as effective and successful curing methods particularly where the SCM is used as a repair material or in architectural elements, respectively.

Abstract:This paper presents the results of an ongoing research on the effect of different curing regimes on properties of Ultra high performance concrete (UHPC) containing recycled steel tire wires as micro steel fibers. Outstanding properties of UHPC as next generation of concrete make it a promising material for different structural applications. The effects of different curing conditions on the mechanical properties of UHPC have been investigated by many researchers. However, limited research works are available that investigates the effects of different curing regimes on transport properties of UHPC.At this paper, different regimes of water curing (WC), air curing (AC), accelerated water curing (AWC) and autoclave curing (AUC) are applied on UHPC specimens containing 2 percents of recycled steel fibers (by total volume). The compressive strength and flexural strength are measured as mechanical properties. Water absorption, sorptivity (rate of water absorption) and pulse velocity tests were investigated on UHPC specimens in various curing regimes as transport properties and durability indexes. Results show that recycled fibers can be successfully used in UHPC mixes to produce an affordable and eco-friendly material. It has been found that both of strength and transport properties of UHPC can be significantly affected by applying the accelerated curing methods. Lack of attention on choosing an appropriate curing condition can lead to a significant increase in water absorption and sorptivity of UHPC.

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