Pozzolanic Reactivity of Cement with Soda-lime Silicate and Borosilicate Waste Glass Powder in Concrete Production

The aim of this research is to study the pozzolanic reactivity of cement with waste glass (Soda-lime Silicate and Borosilicate) in Concrete. When waste glass particles are ball-milled to micro size powder, it is expected to undergo pozzolanic reactions with cement hydrates, forming secondary Calcium Silicate Hydrate. This research looked at the chemical analysis using X-Ray fluorescence (XRF) technique and found some differences in the chemical composition of soda-lime silicate and borosilicate waste glass. The major oxides detected were combined proportion of SiO 2 , Al 2 O 3 , and Fe 2 O 3 with percentage value of 73.202%, 72.998%, 0.411%, 0.201%, and 0.223%, 0.112% respectively. The Setting time of the specimens that contains waste glass powder was also determined and found that it delayed initial and final setting time, and the effect increases as the percentage replacement of cement with waste glass powder increases. The microstructural characterization was also carried out using Scanning Electron Microscope (SEM) and X ‐ Ray Diffraction (XRD) to characterize the concrete samples. It was found that the morphology of concrete samples with waste glass powder (10%) was denser than the control sample (0%). Also, XRD results indicated that the intensity of the peaks, in particular of portlandite, is significantly reduced in the 10% waste glass sample than the control (10% of portlandite in the control, 2% of portlandite in 10% waste glass replacement). Various compositions of the samples (Control 0%, 5.0%, 10%, 15%, and 20%) of concrete cube, cylinder and beam samples were prepared and tested for strength at 7, 14 and 28 days of curing. The compressive strength test results of the control and the 10% waste glass replacement were 20.95 N/mm 2 , 16.44 N/mm 2 for 7, 26.52 N/mm 2 , 24.14 N/mm 2 14, and 31.38 N/mm 2 , 28.82 N/mm 2 28 days respectively. The tensile strength test results of the control and the 10% waste glass replacement were 2.08 N/mm 2 , 1.65 N/mm 2 for 7, 2.65 N/mm 2 , 2.41 N/mm 2 14, and 3.13 N/mm 2 , 2.89 N/mm 2 28 days respectively. The flexural strength test results of the control and the 10% waste glass replacement were 3.96 N/mm 2 , 3.17 N/mm 2 for 7, 4.95 N/mm 2 , 4.58 N/mm 2 14, and 5.87 N/mm 2 , 5.27 N/mm 2 28 days respectively. It can be concluded that all the samples can be used for structural purposes, this is because all the samples exceeded the maximum strength specified by ASTM 24.2 N/mm 2 at 28 days.