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This work is an experimental investigation of the flexural properties of hybrid matrix composites reinforced with different types of reinforcement, namely short glass fibers, glass beads, and short steel fibers. The aim of this investigation is to determine the mechanical behavior and properties of the composites that were manufactured, as well as to define an optimum composition of the materials used that will result in a composite with enhanced mechanical performance for building applications.

In this work, an experimental procedure was conducted to investigate the effect of weight content of short E-glass fibers on the degradation of flexural properties of a hybrid building material, when exposed to a direct gas (propane/butane) flame for varying time intervals. This experimental procedure is aiming on one hand to define the role that E-glass fibers play on the degradation of the flexural properties of the materials tested, as well as to provide a sufficient quantity of experimental data which will allow to quantitatively predict the observed degradation of the aforementioned properties due to exposure to direct gas flame using the Residual Property Model (R.P.M.) developed by the first author and already successfully applied to a number of different materials subjected to a combination of different damage sources.

The objective of this experimental work is the investigation of the viscoelastic behavior of a hybrid matrix, fiberreinforced building material. Hybrid matrix consisted of epoxy resin mixed with fine marble sand, whereas short steel fibers were used as reinforcement. The experimental procedure involved, first, the manufacturing of specimens using different hybrid matrix types and different reinforcement by weight ratios. Subsequently, bending relaxation experiments at room temperature were executed, under three-point bending test experimental configuration, at different strain levels and the variation of stress of the hybrid matrix material with time was monitored. The data obtained were used to (i) investigate the effect of reinforcement mass fraction contained in the composite on the viscoelastic behavior and (ii) to apply existed and newly developed viscoelastic models for the description of the observed viscoelastic behavior. More precisely, the four-parameter (Burgers) viscoelastic model and the modified Residual Property Model were calibrated and used to simulate the relaxation behavior of the materials manufactured and tested. Experimental results exhibited a clear influence of both reinforcement ratio and initial displacement on the viscoelastic behavior of the materials manufactured and tested, whereas the models proposed and used can adequately reproduce the variation of relaxation stress with time.