About Concrete
Concrete is a truly sustainable construction material. With a 100 year service life (compared to an average 50 year service life for wood), building with concrete conserves natural resources by reducing the need for reconstruction. Composed of roughly 80 to 90% naturally-occurring raw materials by weight, concrete requires minimal processing. The ingredients of concrete are cement, water, sand and gravel. Cement, the only component that requires energy-intensive processing, accounts for only 10 to 15% of concrete's total mass.
The land disturbed in extracting the raw materials needed to make concrete is only a small fraction of the environmental footprint created in harvesting forests. Mimicking the very trees that it saves, concrete absorbs carbon dioxide throughout its lifetime through the process of carbonation, further helping to reduce its carbon footprint.
As a virtually inert material, many recycled post-consumer waste products and industrial by-products can be used in the composition of concrete. Slag, fly ash, and silica fume are just a few of the former waste materials that are now being used in cement and concrete production.
Energy Efficient
Because the ingredients for concrete are abundant and readily available, it is generally produced locally, meaning the energy used in transporting concrete is normally quite low. It is not uncommon for all of the ingredients of a concrete pour to be manufactured within 100 kilometres of the job site, compared with thousands of kilometres for wood and steel.
In addition, the high thermal mass of concrete delivers year-round improvements in the energy efficiency of a building. By storing and releasing the energy needed for heating and cooling, concrete naturally resists temperature swings, helping to reduce heating and cooling costs.
Fire Protection
Concrete structures are more fire-resistant than any other form of construction, including steel-frame. Concrete is inflammable, and therefore does not produce any smoke or toxic gases - the most common cause of deaths in structural fires. Neither the smoke, the heat, the flames, or the water used to extinguish a fire seriously affect the structure of concrete walls and floors. This makes cleanup and repairs after a fire in a concrete structure comparatively easy,
A serious fire is about 12 times more likely to develop in a conventional wood-frame home than in a home built out of concrete. Only 10% of homes built with concrete are unsalvageable after a serious fire. 50% of those made with wood have to be demolished.
Weather Protection
Reinforced concrete also provides the best available protection from hurricanes, tornadoes and earthquakes. In tests, concrete walls have routinely withstood winds well above 300 km/h. When installed by a professional, reinforced concrete also holds up very well to the freeze/thaw cycle.
Because of these inherent properties, insurance companies often offer rates 15% to 25% less for home insurance on concrete homes than they do for comparable homes built with standard wood framing.
Health and Wellness
Concrete structures generally have excellent indoor air quality. After a standard 28 day cure time, concrete becomes completely inert, with no off-gassing or release of volatile organic compounds, as can happen for months or even years for conventional wood-frame structures. That means that commercial and residential concrete structures make a healthier living environment than structures made of wood or steel, and can be occupied sooner after construction is complete.
Concrete does not rust or rot, nor does it provide any nutrients for the growth of mould or mildew. Concrete also has excellent sound-damping properties. Even when sound passing through glass windows is considered, a concrete home is generally about 70% quieter than a comparable wood-frame house.
Completely Recyclable
When concrete finally reaches the end of its (often centuries-long) service life, it can be crushed and reused as granular fill in new construction projects. This helps reduce the need to quarry for new construction materials.