چكيده به لاتين
Due to its chemical and silicate structure, blast furnace slags have been receiving the attention of researchers for several years as an alternative to Portland cement. The reaction of slag and Portland cement hydration products improves the durability of concrete. Increasing the durability of traverse concrete against chlorine ion attacks is of great importance in areas of the railway that are prone to this damage. Therefore, in the present research, part of the cement used in the traverse concrete has been replaced with pulverized blast furnace slag. Five mixed designs with replacement of 0, 10, 20, 30 and 40 percent of cement with blast furnace slag with a low water-cement ratio and without any alkaline activator, super-lubricant, water reducer and cubic (compressive strength test) and cylindrical samples ( Chlorine ion migration test) was made in real processing conditions (concrete traverse processing conditions in Karaj Traverse Factory). In the following, non-destructive tests and scanning electron microscope images have been performed to justify the compressive strength and RCMT tests. The results of the compressive strength test on samples containing blast furnace slag show that adding 20% of slag at the age of 1 day has the highest resistance. At the age of seven days, the compressive strength of the samples containing 30% blast furnace slag exceeds that of the design containing 20%, and at the final ages, the compressive strength of the sample containing 40% slag also exceeds the resistance of the 20% sample. Meanwhile, the resistance of the sample containing 10% of blast furnace slag at all ages is lower than the sample without slag, which could be the reason for the error in the sample construction. The increase in compressive strength of the samples containing 20, 30 and 40% slag at the final ages is not very impressive compared to the samples without blast furnace slag. The aim of the present study was not to increase the compressive strength. However, the concrete samples containing 20, 30 and 40% blast furnace slag at all processing ages have met the minimum compressive strength mentioned in publication 301. Due to its silicate structure, blast furnace slag participates in cement reactions and hydration products, and by consuming calcium hydroxide and forming stable silicate gels, it leads to modification of pore size, modification of grain size and cracks created in concrete, and durability of concrete traverse against ion penetration. Chlorine increases. The results show that the use of 10, 20, 30 and 40% of blast furnace slag has caused a decrease of 20.38, 52.51, 69.41 and 86.41% respectively in the migration coefficient of chlorine ion penetration in concrete. The results of non-destructive tests (longitudinal wave propagation in saturated and unsaturated concrete environment) confirm the results obtained about the behavior of traverse concrete in compressive strength and durability against chlorine ion. Also, the results of SEM images confirm the positive performance of blast furnace slag in reducing calcium hydroxides and forming calcium silicates.
