الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Concrete is one of the most vital materials used in construction throughout the world which ordinary portland cement (OPC) is used as the binder to produce it. The harmful effect of OPC production on environment is well known. Therefore, geopolymer concrete is considered an important alternative material in construction field due to its acceptable mechanical and durability properties as well as being environmentally friendly product. There are many reasons for deterioration of concrete structures all over the world, one of them is sulfate attack. Therefore, concrete resistance against sulfate attack is an essential property for materials used in construction field. Different geopolymer and OPC mortars were manufactured to assess magnesium sulfate resistance. The principal objective of this study is to evaluate early- age properties of geopolymer mortar considering several parameters as temperature used for curing, molarity of sodium hydroxide solution (NaOH), alkaline solution to binder ratio (A/B) and type of binder and also the influence of these parameters on geopolymer mortar resistance against magnesium sulfate attack and compare it with OPC mortar. Specimens were submerged in 10% magnesium sulfate solution up to 48 weeks. The evaluated properties in this research were setting time, water absorption and voids ratio, visual inspection, weight change, compressive strength, flexural strength, expansion strain and microstructure variation. Results indicated that binder type has a considerable effect on the mentioned properties. Also the increase in curing temperature, molarity of sodium hydroxide solution and the decrease in alkaline solution to binder ratio improved mechanical properties and enhanced magnesium sulfate resistance of geopolymer mortar with different binders. Mixes containing 50 % fly ash, 35 % ground granulated slag (GGBS) and 15 % silica fume yield the best properties and achieved the best performance in magnesium sulfate solution. Generally, the performance in magnesium sulfate solution is found to be better for various geopolymer mortars compared to OPC mortars.