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Highlights: [•] A systematic study regarding strain sensing function on CFRCCs is reported. [•] The combined effect of fiber’s aspect ratio and percolation level has been studied. [•] CFRCC strain sensors with longer fibers showed higher sensitivity, gage factor. [•] Sensor’s sensitivity was also highly influenced by the percolation level achieved. [•] Non-percolated CFRCC can be used as highly sensitive strain sensors. [ABSTRACT FROM AUTHOR]

Thermal conductivity, specific heat capacity, thermal diffusivity and linear thermal expansion coefficient of two types of carbon fiber reinforced cement composites are measured in the temperature range up to 800°C. Thermal conductivity and thermal diffusivity are also determined for the specimens exposed to thermal load up to 800°C before the measurement. Differential thermal analysis (DTA), mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) are utilized for the assessment of thermal decomposition processes taking place in the high temperature range under consideration. The high temperature thermal properties of the studied materials are found to be positively affected by the application of the high alumina cement and in the case of the Portland cement based composite also by using the autoclaving procedure in the production process. Also, the randomly distributed carbon fibers that can reduce the damage of the pore structure by the thermal decomposition processes are identified as a positive factor in this respect. A comparison of thermal conductivity vs. temperature curves obtained for the specimens pre-heated to different temperatures is found to be a useful tool in the identification of major dynamic effects in the specimens due to the thermal decomposition reactions. The results are in a good agreement with the DTA, MIP, SEM and XRD analyses. The character of the thermal conductivity measurements that in fact includes the effects of convection and radiation into the thermal conductivity coefficient can be beneficial for a simple assessment of the influence of the fire on a dividing structure. [ABSTRACT FROM AUTHOR]

Both liquid water and water vapor transport properties were studied for two different types of carbon fiber reinforced cement composites in dependence on thermal load up to 1000 °C, tensile stress up to breaking value and their combination. The basic mechanical properties, namely the tensile strength, Young''s modulus and hydric strain were analyzed as well. The pre-heating temperature was identified as the most important factor affecting all the studied parameters. Among them, the moisture diffusivity was found as the most sensitive parameter to the thermal load. The differences between its values for reference specimens and for specimens pre-heated to 1000 °C achieved up to two orders of magnitude. For the other parameters, these differences were up to four times the reference value. The effect of tensile load on both hydric and mechanical properties was not observed. The combined effects of tensile and thermal load were not found to lead to any significant differences compared to the thermally loaded specimens. Comparing the effects of thermal load on hydric and mechanical properties, it was observed that the results obtained for the tensile strength were in a good correlation with the data for moisture diffusivity. [Copyright &y& Elsevier]