Experimental study on creep of lightweight one-part alkali-activated slag concrete Ehsan Nosoohi Dehnavi Ehsannosoohi@gmail.com September 19, 2020 Department of Civil Engineering Isfahan University of Technology, Isfahan 84156-83111, Iran Degree: M.Sc Language: Farsi Supervisor: Dr. Kiachehr Behfarnia Kia@iut.ac.ir Nowadays, environmental pollution and increasing greenhouse gases emissions are the main human concerns. One of the main sources of greenhouse gases emissions is the cement production process. According to the researches, about 7.5% of the greenhouse gases entering the atmosphere is due to the cement production process, which is increasing day by day with the increase of construction and demand for concrete production. In recent years, researchers have explored the possibility of replacing cement with other materials. Accordingly, the possibility of replacing an aluminosilicate with an alkaline activator has been extensively investigated. Concrete made with an aluminosilicate source and alkaline activator is called alkali-activated concrete. Alkali-activated concrete is divided into two categories, one-part and two-part. In the two-part type, a combination of alkaline activators is used as a solution in water, but in one-part alkali-activated concrete, a powdered alkaline activator is used. Most of the researches done in the field of alkali-activated concretes were two-part and in the field of one-part alkali-activated concretes the research information and records are very little. The one-part type of alkali-activated has more commercialization potential and does not have the risks of using solutions and the poisoning caused by them. Also, according to researches, the use of slag, which is a by-product of metal smelting industries and is found in abundance in our country; as an aluminosilicate precursor, has been very common due to the high similarity of its compounds and products with cement hydration compounds and products, as well as the desired properties of the concrete made. The study of long-term properties of concrete is an important and effective factor in the design of concrete structures. One of the most important long-term properties of concrete is shrinkage and creep. These changes in concrete volume must be taken into account in structural calculations. The main cause of creep in concrete is the intensity of the load on it. Increasing the rise and even buckling of structural members, especially in high-rise structures, creating decentralization in the load for thin columns and high spans, and reducing the prestressing force in prestressed bridges, which is the main factor. The failure of these structures is due to the destructive effects of creep. Lightening of structures is also important to reduce the seismic force and also reduce the dimensions of the sections of the structure. One of the ways to reduce the weight of the structures is to use concretes made with lightweight structural aggregates. In the present study, one-part alkali-activated slag concretes has been made. Slag with a content of 400 and 450 kg / m3 was used in the mixture design and the activator used was 5-aqueous sodium metasilicate pentahydrate with a ratio of 0.2 content of slag. For aggregates, lightweight structural Leca and ordinary fine-grained and coarse-grained calcareous aggregate were used as variables. After making concrete, properties such as fresh concrete slump, volumetric mass, 7, 28 and 90 days’ compressive strength, water absorption and its shrinkage and creep under two types of curing including wet curing and plastic cover curing, were investigated and the results have been presented. Heat curing also were investigated for compressive strength and water absorption tests. According to the results, the compressive strength of alkali-activated slag concrete samples at all ages were higher than similar ordinary portland cement concrete samples, and in the meantime the final compressive strength of concrete with water curing were higher than the other two types of curing. The water absorption of one-part alkali-activated slag concrete increased with the addition of lightweight aggregate and the increase of slag content. The shrinkage of one-part alkali-activated slag concrete samples and lightweight one-part alkali-activated slag concrete samples were 1.5 and 1.35 times that of concrete made of Portland cement type 1, respectively. Also, the creep in one-part alkali-activated slag concrete samples was about 3 times of that in ordinary portland cement concrete samples. Key Words Lightweight One-part Alkali-Activated Slag Concrete, Structural Lightweight Aggregate, Sodium Metasilicate pentahydrate, Drying Shrinkage, Creep, Curing