Mechanical behavior of heterogeneous composite materials reinforced by fiber glass mesh

In our times, energy has become essential for the welfare and the survival of humans and its availability is crucial for the national economy and growth. The social, geopolitical, and ecological, crises reflected respectively in the lack of thermal comfort in homes combined with expensive energy bills of the low-income households, the energy dependency especially in terms of fossil fuels, and the global warming demand the reduction of the energy consumption. In France, the heating systems of buildings represent 45% of the total energy consumption and are responsible for 27% of greenhouse gas emissions. Thermal insulation including the External Thermal Insulation Composite System (ETICS) has a big impact on the energy consumption and CO2 emissions increasing, at the same time, the thermal comfort of the residents and decreasing their energy bills. The fiberglass mesh reinforced rendering mortar is used as the external protective layer of ETICS. Many defects may attain the ETICS including the cracking of the rendering mortar. These defects may impair the thermo-mechanical performance of the ETICS. The cement-based mortar undergoes chemical, thermal, and hygral strain which, when restrained, cause stress that may attain the tensile strength of the material and cause the mortar cracking. The fiberglass mesh is proposed as a solution for cracking. The behavior of the composite reinforced mortar is a combination of the behavior of each of its components, the mortar and the fiberglass mesh. The former is a chemically evolving material which may also be affected by other conditions such as its hygral conditions. The behavior of the rendering mortar is thus investigated with respect to its age and its curing conditions among other parameters. In a second part, going further in the comprehension of the reinforced mortar mechanical behavior, this study focuses on the fundamental understanding of the reinforcement mechanisms of the fiberglass mesh within the mortar with respect to cracking. X-ray tomography in-situ 3-point and 4-point bending tests are carried out and several reinforcement parameters are considered. The tomography scans enable unveiling the role of the glass fiber mesh on crack localization and crack propagation in reinforced mortar. This work provides physical insights on the reinforcement mechanisms of fiberglass mesh on mortars contributing to the optimization of the cement-based reinforced composites especially in ETICS.