Résumé
Glass fibre-reinforced polymers, thanks to their high performance combined with low weight, are widelyused in many sector. However, at the end of their life cycle, these materials are difficult to recycle, due tothe dfficulty of separating the glass fibre from the matrix (thermoset resin). The incorporation of recycledglass fibre reinforced polymer (rGFRP) in cementitious materials is an interesting recycling and valorisationmethod. This involves cutting glass composites into small pieces and using them as aggregates. However,add rGFRP particles as aggregates in cementitious materials generally leads to reduction in workability andan improvement in certain mechanical performances. The aim of this study is to examine the effect ofdifferent size fractions (0.063 mm, 0.16 mm, 0.63 mm, 1.25 mm and 2 mm) of rGFRP on the mechanicalbehavior of mortar. In this way 10% by volume of the sand is replaced by rGFRP particles. The density ofrGFRP particles is lower than that of sand, ranging from 1.6 to 2.7 g/cm3. Six mortar formulationsincorporating rGFRP particles were carried out, varying the particle size in the different mixes. Eachformulation is designed by a letter from A to F. Formulations A, C and F consist of a single rGFRP particlesize of 0.063 mm, 0.63 mm and 2 mm respectively. For forlumations B, D and E, a mixture of differentparticle sizes is performed, consisting of 1.25 – 0.16 mm, 1.25 – 0.063 and 0.16 mm respectively, and acomplete mixture of all particle sizes for formulation E. Mortars are manufactured in a accordance withstandard EN 196–1, in an automated mixer. After manufacture, the consistency is measured (spreaddiameter), then prismatic samples (4 × 4 × 16 cm3) are made, for subsequent measurement of density,mechanical behavior, water-accessible porosity and microscopic observation. The results obtained showacceptable workability for all formulations and a decrease in the density of mortars incorporating rGFRPdepending on their size, which could be justified by the lower density of rGFRP particles compared withsand particles. Compressive and flexion tests at 7 days and 7 months of curing show a logical inrease inperformance over time due to cement hydration. Figure 1a shows the results obtained in compression test,where the values at 7 months all reach 40 Mpa. Figure 1b shows the percentage variation in compressivestrength of samples with rGFRP. A reduction in comprssiv strength is observed for all samples althoughthis reduction is less significant for samples E and F (<10%). However, the samples A, which contains onlyfine particles, shows the greatest reduction in compressive strength, reaching 31%.Figure 2a shows the results for the flexural strength, with values of around 5 to 6 Mpa at 7 days and 10Mpa at 7 months curing of sample. Figure 2b shows the variation in flexural strength of samples containingrGFRP. A slight decrease in flexural strength is observed for samples B, C, D and E of less than 10% anda slight improvement of around 2.7% for sample F, which showed less brittle fracture during test. A studyof water-accessible porosity after 7 months curing shows a slight increase in porosity for the samples withrGFRP particles, which could account for the drop in density and compressive performance.Finally, microscopic observation of the samples after 7 months curing reveals the presence of rGFRPparticles in the matrix. Particle agglomeration is observed for the formulations with very fine particles(Sample A), and for the formulations containing 2 mm particles (Sample E and F), glass fibre filaments areobserved dispersed in the matrix, potentially improving resistance to crack propagation. However, the vastmajority of fibres are astill grouped in bundles. Thus, after 7 months of curing, the non-alkali resistant glassfibres remain present and show no degradation.