Effect of elevated temperature on strain-hardening engineered cementitious composites

Abstract

h i g h l i g h t sEngineered cementitious composite is proposed for spent nuclear fuel storage. High temperature effect on ECC uniaxial tension properties is characterized. ECC has high spalling resistance after 6 h of exposure to 600°C. ''Spider web'' nano-cracks are absent in ECC at temperatures up to 600°C. The change in ECC microstructure explains its mechanical properties deterioration. a b s t r a c tStrain-hardening engineered cementitious composite materials (ECC) is proposed to substitute quasibrittle concrete materials for building extended spent nuclear fuel (SNF) storage systems in nuclear power plants. While most of ECC properties have been established under normal temperature, the study aims at understanding ECC material behavior under elevated temperature that is expected in a SNF storage environment. On the composite level, ECC specimens were characterized at various temperature levels up to 600°C under both uniaxial tension and compression. The elevated temperature effect on tensile strength and strain capacity, compressive strength and failure mode, moisture loss, and spalling behavior was studied. On the microstructure level, optical microscopy and scanning electron microscopy were conducted to probe the degradation of components, and the change of pore structures due to fiber melting within ECC. The results will provide crucial data and insights for future studies of re-engineering ECC with robust properties specifically desired for nuclear engineering applications.

Effect of Elevated Temperature on the Compressive Strength and Durability Properties of Crumb Rubber Engineered Cementitious Composite

“…Consequently, cracks and subsequent spalling of the sample occur. In most cases, when the temperature becomes higher, the spalling is explosive [18,19]. At 170 • C and 230 • C, the CR and PVA fiber, respectively, melted, creating pathways for the water vapor to escape, thereby alleviating the development and propagation of cracks in the CR-ECC at elevated temperatures.…”

Behaviour of fibre-reinforced cementitious composite containing high-volume fly ash at elevated temperatures

“…The higher increase in compressive strength of the F-series specimen compared with those of C-series at this temperature could be caused by the increased hydration process of the F-series specimens as explained earlier. Bhat et al [23] also suggested that higher amount of fly ash could contribute to greater increase in compressive strength at this temperature. This was also supported by the findings of Rashad [9] and Khan and Abbas [26], whereby the inclusion of blast furnace slag as partial cement replacement improved the compressive strength of concrete at 400°C, particularly at higher volume replacement, as observed by Rashad [9].…”

“…The mix F0 had the most severe spalling among all of the specimens, and it is interesting to note that the inclusion of acrylic fibres reduced the spalling significantly in FRCC specimens F1 and F2. Spalling could be prevented as a result of enhanced tensile capacity of FRCC with the use of fibres [23]; consequently there would be less cracking and the extent of cracking could be less severe.…”

Fire performance of ductile fiber reinforced cementitious composites

“…Different trends in strain capacity of DFRCC were found below 200 °C, possibly due to use of different DFRCC mixes. Above 250 °C , DFRCC lost its strain-hardening behavior (Bhat et al 2014, da Silva Magalhã es et al 2015.…”

“…In general, DFRCC performs similar to or better than concrete or FRC in terms of compressive strength degradation. Limited test data (Bhat et al 2014, da Silva Magalhã es et al 2015, Yu et al 2015 was available for residual tensile properties of fire-damaged DFRCC. Different trends in strain capacity of DFRCC were found below 200 °C, possibly due to use of different DFRCC mixes.…”