Use of Cement Mortar Incorporating Superabsorbent Polymer as a Passive Fire-Protective Layer

Concrete structures, when exposed to fire or high temperatures for a certain time, could suffer partial damage or complete structural failure. Passive fire-protective coating materials are an alternative way to prevent or delay damage to concrete structures resulting from fire. Superabsorbent polymer (SP) is a synthetic material known for its ability to absorb and retain a large volume of water within itself. With this unique property, the SP exhibits great potential for use as a passive fire protection material. Although several studies have been carried out to investigate the effect of SP as a surface coating material for fire protection, very few have been investigated on the potential use of SP mixed with mortar as a passive fire-protective layer. The objective of this study is to introduce the use of SP in plastering mortar as a fire-protective layer for concrete subjected to temperatures up to 800 °C. This study is divided into two parts: (1) investigating the properties of cement mortar mixed with SP at 0.5% (CONC/SP-0.5) and 1.0% (CONC/SP-1.0) by weight of cement, and (2) investigating the potential use of SP mortar as a plastering layer for concrete subject to high temperatures. The experimental results showed that the density and compressive strength of SP mortar decreases with increasing SP dosages. From the heat exposure results, SP mortar exhibited lower strength loss due to the ability to mitigate moisture through its interconnected pore system. As for the use of SP mortar as a plastering layer, the results demonstrated the concrete specimen plastered with SP mortar had a lower temperature at the interface and core than that plastered with plain mortar. This led to a reduced strength loss of 20.5% for CONC/SP-0.5 and 17.2% for CONC/SP-1.0.