Presented by the instructor: Assistant Lecturer (M.Sc.) Kawthar Haidar Abdul Latif Department of Civil Engineering, Al-Mustaqbal University Concrete is one of the most widely used structural materials in the world, yet its reliance on Portland cement gives its production a noticeable environmental impact. Cement production consumes large amounts of energy and generates high emissions of carbon dioxide, estimated at about 5 to 8% of global emissions, which has led researchers to search for alternative binding materials that maintain structural performance while reducing environmental impact. In this context, geopolymer concrete has emerged as one of the most promising solutions in the field of sustainable construction. Geopolymer is an inorganic binding material produced by the reaction of silica- and alumina-rich source materials, such as fly ash, ground granulated blast-furnace slag, and calcined kaolin, with alkaline activating solutions, most often sodium hydroxide and sodium silicate. This reaction, known as alkali activation, produces a three-dimensional network of silicate-aluminate bonds that binds the aggregates together and forms a solid material with good strength. Thus, concrete can be produced without using Portland cement, or with a very small proportion of it. The main environmental benefits of this technology include a lower carbon footprint compared with conventional cement, as many studies indicate that emissions can be reduced by up to 40% or more, depending on the type of source materials and production conditions. This technology also contributes to recycling industrial waste that was previously landfilled or accumulated in the environment, such as fly ash from power plants, which supports circular economy concepts and reduces pressure on natural resources. From an engineering perspective, geopolymer concrete has distinctive properties, including strength gain at early ages under heat curing, good resistance to chemical attack, sulfates, and acids, and the ability to withstand high temperatures and fire better than conventional concrete in many cases. These properties make it suitable for structures exposed to harsh environmental conditions, such as sewage networks, marine structures, and precast concrete elements. However, there are still challenges that limit its widespread adoption, most notably the need to handle the alkaline activating solutions safely because of their corrosive nature, and the variation in the properties of source materials from one source to another, which requires precise control of mix designs. In addition, some mixes require heat curing to achieve adequate strength, which may limit their use in cast-in-place applications, along with the scarcity of unified engineering codes for them compared with conventional concrete, and the high cost of some activators in certain markets. Recent research is moving toward developing geopolymers that can be cured at room temperature, using less harmful activators, improving long-term durability, and preparing standard specifications that will contribute to their commercial adoption. This technology is expected to play a growing role in the future, particularly in countries where industrial waste or suitable natural materials are available for its production. In conclusion, concrete made with geopolymer cement represents an important step toward more sustainable construction, owing to the emissions reduction, utilization of industrial waste, and good engineering performance it offers. The success of its application remains dependent on precise mix design, laboratory and field verification of its properties, and compliance with approved technical requirements and specifications, thereby achieving a balance between performance efficiency and environmental protection.