Hydric and mechanical properties of carbon fiber reinforced cement composites subjected to thermal load

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 degreesC, 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 degreesC 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. (C) 2004 Elsevier Ltd. All rights reserved.