A Study on the Combined Effects of Silica Fume Particles and Polyethylene Terephthalate Fibres on the Mechanical and Microstructural Characteristics of Cemented Sand

In this research, a study was undertaken to investigate the effects of silica fume particles and randomly distributed polyethylene terephthalate (PET) fibres on the behaviour of cemented sand through a comprehensive experimental programme including unconfined compression, pH and microstructure tests. Three cement contents, four contents of silica fume and five percentages of PET fibres with three different lengths were selected. Then, different specimens were prepared and cured for 3, 7, 14, 28, 42 and 56 days. It was found that there are optimum amounts for silica fume content, curing time as well as content and length of PET fibres at which unconfined compressive strength (UCS) presents the best improvement. Based on the obtained results, silica fume inclusion to cemented sand increases stiffness and energy absorption (EA) capacity while decreases pH. It was found that with the increase of PET fibres, stiffness reduces and EA capacity increases. Some relations have also been introduced between stiffness and UCS of silica fume-cemented sand reinforced with PET fibres. Finally, the microstructure features of the samples were investigated through Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analyses. Moreover, X-ray Diffraction (XRD) tests were performed for mineral identification.