Laboratory evaluation of the properties of eco-friendly four-component concretes containing silica fume, glass powder and ground granulated blast furnace slag

These days, concrete is used as an all-purpose material in various industries. Depending on the usage of concrete, different properties can be expected from it. Plentiful usage of concrete in different industries such as bridge construction, landscaping, construction structures, ports, piers and special structures have made this valuable material the center of attention of many researchers. Depending on the type and place of using concrete, this material has limitations and problems. Concrete demolition in long period of time is one of the causes of irreparable damage to the industrial and economic cycle of countries. High durability and reliability concretes reduce irreparable damage to the environment also increase the service life of structures. Factors affecting the service life of concrete structures, environmental conditions and concrete quality. The attack of sulfates on concrete is one of the important factors in reducing the life of the structure and the durability of concrete. Sodium, magnesium and calcium sulfates are salts, which usually found in soils and groundwater that hydrated with various phases of cement paste, such as hydrated aluminum, monosulfate hydrate, and calcium hydroxide and form needle-bearing crystals.The volume of these crystals is more than the volume of the raw materials of cement paste, so they cause cracking in hardened concrete. Magnesium sulfate has a more destructive effect than other sulfates because it destroys calcium silicate hydrate (C-S-H) as well as hydrated C3A and Ca(OH)2. Then, due to the attack of sulfates on concrete, magnesium silicate hydrate is formed, which has no adhesive properties. The effect of sulfate attack on concrete depends on their concentration and permeability of concrete. If the concrete is very permeable, water will easily penetrate into it and Ca(OH)2 will be lost. Evaporation on the concrete surface leaves calcium carbonate deposits, which are formed by the reaction of Ca(OH)2 with carbon dioxide. This deposit is observed due to the attack of sulfates on concrete with a white appearance. The loss of Ca(OH)2 will increase the porosity of the concrete, making it consistently weaker and more susceptible to chemical attacks by sulfates. In the present study, weight change and resistance pressure tests for placement in magnesium sulfate solution of six different concrete designs and replacement of cement with silica fume, glass powder and ground granulated blast furnace slag at the ages of 7, 28, 56 and 90 days have been investigated. Also, in order to evaluate the permeability of each mixture, depth of penetration of water under pressure and water absorption were performed on cubic samples. The overall results indicate the performance in favor of silica fume, glass powder and ground granulated blast furnace slag in reducing the rate of sulfate consumption and water reduction. The rate of weight gain and compressive strength against sulfate depends on the properties of cement consumables and their consumption with cement.