As the world continues to urbanise many countries will face challenges in meeting the needs of their growing urban populations, including for housing, transportation, energy systems and other infrastructure, as well as for employment and basic services such as education and health care.
68% of the world population are projected to live in urban areas by 2050
According to the United Nations 68% of the world population are projected to live in urban areas by 2050.
As the world continues to urbanize many countries will face challenges in meeting the needs of their growing urban populations, including for housing, transportation, energy systems and other infrastructure, as well as for employment and basic services such as education and health care.
Close to three in five cities worldwide with at least 500,000 inhabitants are at high risk of a natural disaster. Collectively, these cities are home to 1.4 billion people or around one third of the world’s urban population.
Concrete is a versatile building material, in fact the most man-made used substance after water. Concrete is made of cement, sand, aggregates, water and admixtures. It can be moulded when in its “wet” state and solidifies over time, gaining strength and durability.
Cement is the ‘glue’ which binds the ingredients of concrete together. It is a powdery material which when mixed with water, sand and gravel forms concrete. When mixed with water and sand it makes mortar.
How are cement and concrete made?
Further definitions can be found in the glossary.
Properties of concrete
Non-flammable – Concrete does not burn: providing fire safe structures
Rust-resistant – Concrete does not rust: providing low maintenance
Rot-proof – Concrete does not rot: reducing risk of unseen damage
Insect-proof – Concrete does not suffer from insect damage: reducing risk of unseen damage
Flood-resilient – Concrete does not swell and warp when wet: providing resilience to flooding and internal water damage
No emissions – Concrete does not emit volatile organic compounds (VOCs): these are an issue with other building materials and impact health
Water-safe – Concrete is inert: it can be used to store and supply clean drinking water
Heat-reflective – Concrete has high albedo: the light-coloured surface of concrete reflects heat whereas dark surfaces like asphalt absorb heat and cause the problematic urban heat island effect
Water-permeable – Concrete paving can be permeable to water: when it rains water can permeate through to reduce surface flooding
Vehicle emission reducing – Concrete paving is stiff and rigid: vehicles have lower emissions on rigid roads
Thermal mass – Concrete has thermal mass, like stone and masonry, which can be used by designers to reduce energy demand.
Range of Densities Possible – Concrete can be made in a range of densities from lighter than water (10kN/m3) to heavy concretes (30kN/m3) that are used in hospitals to absorb radiation: typical concrete density is 23kN/m3
Compressive strength – Concrete has compressive strength: strengths from 5MPa (economic low strength masonry) to 80MPa (high rise buildings) and can be designed to have more than double this strength for ultra high performance
Tensile strength – Reinforced Concrete has tensile strength: concrete is compatible with reinforcement steel which provides tensile capacity and together they make the most widely used composite material in the world
Available & Affordable – Concrete is locally produced. It is widely available and suitable to build at a reasonable cost, without compromising on quality and strength and with low maintenance costs
Recyclable – Concrete is one hundred percent recyclable. All its components are recyclable which can support a circular economy
Whole-life benefits – Taking a whole-life cycle performance into account, concrete has a low carbon footprint thanks to its durability, to its thermal mass effect, to its recyclability and to the carbonation of cementitious materials.
To meet the demands of society, cement production is 4.1 billion tonnes. By country in percentage terms: China 52%, India 6.2% and EU28 5.3%. USA 1.9% and then Turkey, Indonesia, Brazil, Russia, South Korea and Saudi Arabia (CEMBUREAU 2018 activity report).
Based on population and development, the IEA CSI Cement Technology Roadmap predicts that global cement production is set to grow by 12‑23% by 2050.
Cement and concrete are typically manufactured locally because raw materials are available, and transportation is relatively expensive.
Quarries are usually restored after extraction and this results in a net positive gain for the nature. We aim at promoting best practices globally.
According to different independent stakeholders, cement manufacture is responsible for between 5%‑8% of global GHG emissions (GCCA is working to provide an accurate assessment – early indications suggest the figure is closer to 5% when GHG emissions from all sectors are considered).
The cement industry has reduced CO2 by 19.2% per tonne cementitious since 1990 (2018 GNR data).
Restoration returns sites of extraction in many countries to the environment. These support schemes to promote biodiversity, and best practice is being promoted globally.
Header Photo by Daisy S on Unsplash