Role of Alkaline Constituent On Properties And Microstructure of Crushed Rock Based Alkali-Activated Material For Low Strength Applications
Abstract A more sustainable and innovative cementitious material would serve green construction for the future and could yield tremendous leverage to the problem of CO2 emissions. Alkali-activated materials (AAMs) could be an alternative binder for relatively low strength construction and rehabilitation as a cement replacement material. The lower strength requirements, e.g., road construction materials, compared to other applications could ease any difficulties with AAM production. For this study, crushed rock (CR) was used as the prime material of a precursor. A laboratory investigation of mechanical properties was performed in conjunction with XRF, XRD, and SEM techniques. The results showed that CR-based AAM with an optimum mixture of 5 M of NaOH concentration, an SS/SH ratio of 1.0, and a liquid-to-binder (L/B) ratio of 0.5 could be used a part of relatively low strength materials. At this ratio, the paste samples cured at room temperature (25 ⁰C) had an early compressive strength of 3.82 MPa, and the paste samples cured at 60 ⁰C had an early compressive strength of 6.45 MPa. The results passed the target compressive strength of cementitious construction materials such as construction block (3.0 MPa–7.0 MPa) and cement-treated base (CTB) for pavement (2.1 MPa–5.5 MPa).