The effect of kaolin use on the strength and durability properties of self-compacting mortars

The aim of this study is to investigate the effect of mineral additive use on the strength, durability and viscosity properties of self-compacting mortar (SCM). Both fresh and hardened mortar properties were investigated to determine the high strength, durability and optimum workability properties in concrete production. The substitution of mineral additives (silica fume, fly ash, blast furnace slag, kalsine kaolin etc.) for cement affects significantly the fresh and hardened properties of mortars. To add new ones also to the regional mineral additives that are replaced with cement will contribute both local and national economy. In this study, river aggregate was used as normal aggregate in size of 0-2 mm and 2-4 mm in self-compacting mortar (SCM). %5, %10, %15 and %20 kaolin (K) and %5, %10, %15 and %20 calcined kaolin (MK) which were obtained by calcining at 600 ºC for 5 hours were used as mineral material instead of CEM I 42.5 N type portland cement. In the series, the total amount of binder material of 630 kg/m3 and 8 kg/m3 superplasticizer (HTECH36) were kept constant. All mortars were produced at ratio of 0.43 water/binder. 9 different mortar samples including one control sample were designed. In all fresh SCMs, mini-slump flow for self compactibility and viskosity tests for workability and consistence were carried out. In order to determine the hardened properties of SCMs, density, porosity, total water absorption and capillary water absorption tests were performed on 5x5x5 cm cube samples. Flexural strength, compressive strength and high temperature tests were performed on 4x4x16 cm prismatic samples. According to test results, the fresh properties of the mortars with the mineral additive have complied with the criteria of self-compactibility. The flexural and compressive strength properties of the mortars have been decreased with the increase of the mineral additive ratio, but the resistance to high temperature have been increased. Keywords: Self-Compacting Mortar, Kaolin, Calcined Kaolin, High Temperature