Self-healing characteristics of cement concrete containing expansive agent

Abstract

Many studies have been conducted to identify the self-healing effect in cementitious materials. However, the knowledge regarding the self-healing effect is insufficient to utilize this effect for design purposes. This study examined the influence of numerous admixtures such as expansive agents (EA), ultra-fine fly ash (UFFA), finely ground granulated blast furnace slag (FGGBS), and silica fume (SF) on the self-healing capacity of Portland cement concrete. Here, focused on investigating the effect of the expansive agent (EA) used in concrete mixtures to identify whether the EA could act as a self-healing trigger in concrete materials that are frequently used in a bridge deck overlay. Ordinary Portland cement concrete (OPC), latex-modified concrete (LMC), and silica fume concrete (SFC) was used to compare the effect of the EA (0,4,8%, and 12%) in the ternary blended cement concrete on each material for bridge deck overlay concrete. In this study, the crack width was examined at 0,7,14 and 28 days respectively which were inducement at 3 and 7 days age of concrete specimens by the microscopic image analysis system. Samples with healed cracks with a width range of 100–200 µm and EA ≥ 8% on day 28 exhibited faster self-healing performance. Additionally, we calculated the self-cracking closing ratio and performed a microstructure analysis by SEM/EDS. Moreover, the compressive strength was examined at 7, 28,56, and 90 days for understanding the improved performance of all concrete mixtures.

Keywords

• Self-healing
• Shrinkage
• Ternary blended concrete
• Expansion agent
• Microscopic image analysis
• Concrete overlay for bridge deck