Determining the Effects of Extreme Environmental Conditions on the Ageing of Macro Synthetic Fiber Reinforced Concrete: A Statistical and Analytical Study

The present study analyzes, from a statistical point of view, the effects of low and high temperatures on the flexural behavior of the different Fiber Reinforced Concretes (FRCs). The data considered are the experimental results obtained in a previous extensive campaign with 434 specimens in total (size 150 × 150 × 600 mm). The temperatures considered are extreme environmental conditions with values from –15 to 60 ℃ that are applied during 3, 90 and 180 days and kept during the flexural test. The FRCs studied are three types of Macro Synthetic Fiber Reinforced Concretes (MSFRC) and one Steel Fiber Reinforced Concrete (SFRC). To identify significant factors and differences among the groups, several analyses of variances (ANOVAs) were performed using the software Stat graphics Centurion. These analyses allowed to stablish relationships between the selected dependent variables (flexural strengths at limit of proportionality and residual flexural strengths at different Crack Mouth Opening Displacement (CMOD) of 0.5 and 2.5 mm) and factors as temperature, time of exposure and state (pre-cracked or non-pre-cracked). These relationships, in turn, provide insights into the practical implications of FRCs, expanding the existing knowledge. As result, simple numerical equations generated by the same software, are presented and proposed as a first approach for future numerical models by each FRC type.