PSI - Issue 52

Cheolwoo Park et al. / Procedia Structural Integrity 52 (2024) 480–486 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Introduction Concrete is an economical construction material with better performance at high temperature exposure than that of others construction materials such as timber and steel, owing to its non-combustibility and low thermal conductivity by Bauchanan and Abu (2017). Conventional concrete is damaged by exposure to high temperatures and will suffer a loss of strength, cracking, and spalling. Slurry-infiltrated fiber-reinforced cementitious composites (SIFRCCs) can be used to provide high compressive strength and ductile behavior to address these problems. SIFRCCs is a relatively new type of concrete that incorporates steel fiber in slurry mix. Due to its high strength and toughness SIFRCC can withstand high impact and blast load compare to conventional concrete. SIFRCCs materials have excellent flexural strength and toughness due to presence of steel fibers. The fibers help to distribute the load more evenly throughout the materials, which prevents the propagation of cracks and enhances the overall toughness of the materials. Because of the better performance of fiber reinforced cementitious composite (FRCC), demands of the different FRCC has increased over the past few years. Mechanical properties of the Slurry-infiltrated fiber-reinforced cementitious composites has been studied by Kim et al. (2020), Kim et al. (2020), Kim et al. (2020). Recently many fire and explosion accident had been occurring. Different countries had promises to increase the use of gases either to replace or minimize the use of fuel. If use of combustion gases increases than the chance of fire accidents can also be increase (Kim et al. 2023). Many researchers had studied and analyzed the effect of high temperature on concrete structure and high performance concrete structure (Xiong and Richard (2015), Ahsanollah et al. (2016), Bhat et al. (2014), Jin and Kang (2018), Kim et al. (2020), Li et al. (2017), Muhammad et al (2017), Wenzhong et al. (2015), Xiong and Richard (2015), Yu et al. (2015). Recently, the study of fiber reinforced concrete structure had been increase, different researcher had done research in different explosion and temperature effect on FRP structure. FRP structure can withstand high impact and blast load due to its high strength and toughness by Kim et al. (2020). The use of polymeric fibers, e.g., polypropylene (PP) and polyvinyl alcohol (PVA) fibers knows as engineering cementitious composite (ECC) materials shows better spalling resistance than that of plain mortar (Jin and Kang (2018). Kim et al. (2020) studied the mechanical properties of the SIFRCC when exposed to high temperature with different percentage of powder polymer and confirm that presence of polymer up to 1.5 % can reduce the failure rate of SIFRCCs structure owing to an unexpected load, such as fire and explosion. To maintain the filling performance of slurry during fabrication of SIFRCCs powder polymer was used by Kim et al. (2020), if organic fiber is used it is difficult to pour the slurry because of the fabrication process of SIFRCCs. The main objective of this study is to compare the flexural strength of SIFRCCs, exposure with high temperature for 1hr. with different percentage of polymer mix SIFRCCs. This study also compares the flexural strength of the SIFRCCs with basalt fiber sheet, exposure in high temperature. High water pressure might arise when exposed to fire due to the high density of SIFRCCs and this pressure degradation the SIFRCCs structure. To reduce the pressure created inside the structure through capillary pore powder polymer was used. Polymer inside the SIFRCCs melts due to high temperature and high heat and it creates the capillary pores, pressure created inside the SIFRCCs structure can release form the pores. Moreover, around the fibers, passes zones to the cement matrix were formed. The existing pass zones between fine aggregates and matrix are interlinked, so permeability increases and the steam pressure is reduced. Therefore, this study evaluated the flexural strength of SIFRCCs before and after exposure to a high temperature using Basalt fiber sheet and powder polymer in replacement of organic fiber. 2. Materials and test method 2.1. Materials Ordinary Portland cement (OPC) type I, silica fume, fine aggregate (FA) with a size of 0.3 mm to 1.0 mm, a polycarboxylic acid high range water reducer (HRWR) and shrinkage reducing agent (SRA) was used Kim et al. (2020). Coarse aggregate was not used for better filling achievement of the slurry. Highly distribution of HRWR and SRA was used to improve the workability and followability of SIFRCC mix. Hooked-end steel fibers with a diameter of 0.75 mm and length of 60 mm with aspect ratio of 80 were used. 1200 MPa the tensile strength of the steel fibers was selected. The steel fiber used for this study contains 5 % by volume fraction. Polymer powder (0.1 µm to 5 µm) was used. The amount of polymer powder added during slurry mixing was 0%, 0.5%, 1.0%, and 1.5%. Basalt fiber