Enhancing self-healing performance of MgO based strained hardening composite

• Main Author: Lau, Zhen Wei
• Other Authors: Yang En-Hua
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Civil engineering::Construction technology
• Online Access: http://hdl.handle.net/10356/75812
• Institution: Nanyang Technological University

The wide usage of Portland cement (PC) concrete especially in construction industry is causing a heavy burden on the environment through its high carbon emission. This is primarily caused by the production phase of PC which requires it to be heated to a high temperature for clicker to form. MgO based cement however can be produced at a much lower temperature, reducing the carbon emission at production. Some MgO based ECCs have portrayed to have a negative carbon footprint. Therefore, this paper focuses on the self-healing capability of MgO based strain-hardening composite (SHC) under the effect of crack width. Specimens were casted using a mix with 0.5% PVA fibre to induce a single crack. The stiffness recovery of the SHC is indicated using a mechanical approach with its Resonant Frequency (RF) value. Specimens were pre-cracked and undergoes a healing regime alternating with water and CO2 for 10 cycles. Result shows that specimens with crack width less than 100µm have demonstrated the ability to attain a mechanical recovery up to 100% RF ratio after the healing cycle. The finding is subsequently backed by the SEM analysis to observe the healing product along the cracks. Overall, the self-healing capability of the MgO based SHC have shown a decreasing trend with the increase in crack width on the specimens.