Deutsch: Beton / Español: Hormigón / Português: Concreto / Français: Bêton / Italiano: Calcestruzzo
Concrete is a composite material composed of coarse granular material (the aggregate or filler) embedded in a hard matrix of material (the cement or binder) that fills the space among the aggregate particles and glues them together.

In the context of the environment, "concrete" refers to a construction material composed of cement, water, aggregates (such as sand and gravel), and often additional additives. Concrete is widely used in infrastructure development, buildings, and various construction projects. While concrete has numerous benefits, such as strength, durability, and versatility, it also has significant implications for the environment. Let's explore the environmental aspects of concrete with several examples and examine some similar materials.

1. Carbon Footprint: One of the key environmental concerns associated with concrete is its carbon footprint. Cement production, a primary component of concrete, is a major source of carbon dioxide (CO2) emissions. The production of cement involves heating limestone and other raw materials to high temperatures, releasing CO2 as a byproduct. According to estimates, the cement industry is responsible for approximately 8% of global CO2 emissions.

2. Land Use and Habitat Loss: Concrete production requires significant quantities of raw materials, including sand, gravel, and water. Extraction of these materials can lead to habitat destruction, particularly in riverbeds and coastal areas where sand and gravel are often sourced. The removal of sand and gravel can disrupt ecosystems, alter river courses, and impact the natural habitats of aquatic organisms and wildlife.

3. Water Consumption: Concrete production is a water-intensive process, particularly during the curing phase when water is necessary for the hydration of cement. High water consumption can strain local water resources, especially in regions prone to water scarcity or drought. Additionally, the discharge of concrete wastewater, which contains high pH and chemical additives, can adversely affect nearby water bodies and aquatic ecosystems.

4. Energy Consumption: The production of concrete requires substantial amounts of energy. The energy-intensive processes include the extraction and processing of raw materials, transportation of materials, and the kiln operations for cement production. Fossil fuels are often used for energy generation, contributing to greenhouse gas emissions and air pollution.

5. Waste Generation: Construction and demolition waste contribute significantly to landfill volumes, and concrete is a major component of this waste stream. When structures made of concrete are demolished or renovated, the resulting concrete debris, known as "concrete rubble," requires proper management. While concrete can be recycled and used as aggregate in new concrete or for road construction, not all concrete waste is effectively recycled, leading to increased landfill burdens.

6. Urban Heat Island Effect: Concrete's high thermal mass and low albedo (reflectivity) can contribute to the urban heat island effect. Urban areas with extensive concrete infrastructure tend to absorb and retain heat, leading to increased temperatures compared to surrounding rural areas. This effect can have negative consequences, including increased energy demands for cooling, decreased air quality, and adverse health impacts.

7. Alternative Materials: In recent years, there has been growing interest in developing alternative materials to mitigate the environmental impact of concrete. For example, researchers are exploring the use of supplementary cementitious materials like fly ash and slag, which can partially replace cement in concrete production and reduce CO2 emissions. Additionally, materials like bamboo, timber, and rammed earth are being explored as sustainable alternatives to concrete in construction projects.

Similar materials to concrete include:

1. Asphalt: Asphalt is a composite material commonly used in road construction. It consists of aggregates (such as sand and stone) bound together with bitumen. While asphalt has its own environmental considerations, such as the extraction of raw materials and its contribution to heat island effects, it has a lower carbon footprint compared to concrete.

2. Timber: Timber is a renewable material widely used in construction. It has a lower carbon footprint than concrete and steel and can store carbon throughout its lifespan. Sustainable forestry practices and certifications ensure responsible timber sourcing.

3. Rammed Earth: Rammed earth is an ancient construction technique that involves compressing a mixture of earth, clay and sand.