Concrete is one of the most reliable, durable, and desired construction materials. It became the second most used material after water in the world. Many studies and investigations reported that the amount of CO2 released into the atmosphere is nearly 1 ton in the production of 1 ton of cement, which contributes to 5-7 % of total CO2 emissions worldwide. Geopolymer concrete (GPC) is a new development in the world of concrete, which does not need to use cement. The most used materials in geopolymer are by-products such as fly ash, ground granulated blast furnace slag, silica fume, etc. Industrial waste materials are a great problem for human health, environment, and scarcity of land, therefore, reusing them in GPC manufacturing can be seen as a great advantage. Fortunately, most of the recent research concludes that most by-products exhibit similar or better durability, mechanical and physical properties when compared to ordinary concrete. Therefore, GPC became a good sustainable engineering material with many advantages over conventional concrete, such as high early strength, excellent resistance to chemical attacks and steel reinforcement corrosion, elimination of water curing, low cost, etc. This paper reviews the process of geopolymer concrete, constituents, types, properties, durability, and particular applications.

Concrete is one of the most used construction materials worldwide. It is known to be a strong and durable material at a reasonable price. The most well-known problem in concrete is the cracks, which affect the service life of the concrete structures and leads to consumes higher costs through maintenance. Cracks allow penetrating any ions into the concrete resulting in other big problems such as corrosion of steel reinforcement, sulphate attack, carbonation, alkali-aggregate reaction, etc. It is impossible to prevent the formation of cracks, therefore they can be controlled or repaired using a variety of methods. Nowadays, self-healing is one of the widely recognized techniques to improve concrete's long-term durability. Healing agents such as bacteria, chemical compounds, and polymers are utilized. In this method, with the help of a healing agent, the cracks start to heal autonomously during crack formation. Since Bacteria is the most used material for healing concrete, self-healing concrete is also known as bacterial-concrete or bioconcrete. This article provides an overview of self-healing concrete including describing the system, process, durability, and mechanical properties of healed concrete.