Flexural behavior of fiber and nanoparticle reinforced concrete at high temperatures

Abstract

Summary In this study, the flexural tests were conducted to investigate the effects of temperature, steel fiber, nano‐SiO2, and nano‐CaCO3 on flexural behavior of concrete at high temperatures. The load‐deflection curves of fiber and nanoparticle reinforced concrete (FNRC) were measured both at room and high temperatures. Test results show that the load‐deflection curves become flatter, and the flexural strength, peak deflection, and energy absorption capacity decrease seriously with the increase of temperature. Both steel fiber and nanoparticles could significantly improve the flexural behavior of the concrete at room and high temperatures. The energy absorption capacity of FNRC before the peak point increases with the increase of steel fiber volume fraction. The improvement of nano‐SiO2 on flexural strength of FNRC at high temperature is better than that at room temperature, but the enhancement on energy absorption capacity is reverse. Nano‐SiO2 is more effective than nano‐CaCO3 in improving flexural behavior of concrete both at room and high temperatures.

Flexural behavior analysis and strength prediction of steel fiber-and-nanosilica reinforced rubber concrete

“…To analyze the effect of SF on the peak flexural strength, abundant test data were collected from this paper and previous researchers (Duzgun et al, 2005; Fu et al, 2019; Gao et al, 2018; Guler et al, 2019; Ismail et al, 2017a; Li et al, 2017; Soulioti et al, 2009; Thomas et al, 2007; Yazc et al, 2007), which related to the hook-shaped steel fiber reinforced concrete, hook-shaped steel fiber reinforced self-compacting concrete, hook-shaped steel fiber reinforced lightweight concrete and hook-shaped steel fiber reinforced rubber concrete. Figure 10(a) presents the relationship of the normalized peak flexural strength and fiber reinforcing index RI(RI = vflf/df) , of which the normalized peak flexural strength is the ratio of the peak flexural strength of SFNS-RC to that of RC.…”

Test methods for characterizing concrete properties at elevated temperature

“…A typical heating device is an electric furnace (shown in Figure ) which can heat a specimen to target temperature at a specified heating rate. Lining the furnace heating chamber with fire insulation can prevent possible damage during abrupt failure of test specimen, as in the case of higher strength concrete specimens which can undergo explosive spalling under certain conditions . The loading device is primarily a strength testing machine (typical example shown in Figure ) that allows the user to monitor and apply load on the test specimen at a specified strain rate.…”

“…Lining the furnace heating chamber with fire insulation can prevent possible damage during abrupt failure of test specimen, as in the case of higher strength concrete specimens which can undergo explosive spalling under certain conditions. 39,40 The loading device is primarily a strength testing machine (typical example shown in Figure 6) that allows the user to monitor and apply load on the test specimen at a specified strain rate. The instrumentation needed for monitoring temperature is thermocouple and for monitoring displacement is Linear Variable Differential Transformer (LVDT).…”

Effect of Macro-, Micro- and Nano-Calcium Carbonate on Properties of Cementitious Composites—A Review

“…Nanoparticles are commonly defined as materials with a particle size of less than 100 nm [ 66 , 67 ], and can make revolutionary changes in bulk material properties [ 68 ]. Incorporation of nanoparticles in cementitious composites can significantly improve their mechanical properties and durability [ 67 , 69 , 70 , 71 , 72 ].…”

“…For high temperature exposure, incorporation of nano-calcium carbonate in cementitious composites can improve its peak compressive stress, ultimate compressive strain, compressive toughness and flexural properties no matter in ambient environment or in/after high temperature [ 68 , 86 , 87 ]. But it is ineluctable for the rapid decrease in strength after 800 °C because of the decomposition of calcium carbonate.…”