Properties of Self-Compacting Engineered Cementitious Composites containing Nano Silica Subjected to Elevated Temperatures

In this study, the properties of Engineered Cementitious Composites with the addition of Nano Silica is investigated when exposed to temperatures of up to 400C. 25 different mix proportions with PVA Fiber up to 2% and Nano Silica up to 4% is use to be molded into cubes of 50mmX50mmx50mm. These concrete cubes are water cured for 28 days before being heated up to temperatures of 100C, 200C, 300C and 400C. Then the residual strength, microstructure and pore characteristics will beinvestigated. Based on the compressive strength results of the concrete , the strength increases as the percentages of Nano Silica increases in the mix. The same also applies as the percentages of PVA Fiber increases. When subjected to elevated temperatures, the samples will show an increase of compressive strength to the temperature of 300C and then reduces at 400C. The morphology and microstructure of the samples are examined .All the ITZ between cement matrix and fiber are determined. The ITZ will decrease as the percentage of Nano Silica increases up to 3%. At 4%, the ITZ will increase marginally due to entrapped air in the fresh mixture thus causing more porosity. The MIP for the samples are done to determine the pore characteristics. The increase of Nano Silica will reduce the accessible porosity of the sample up to 3% addition of Nano Silica. Above that, the porosity of the composite will increase.