What is a sustainable or low impact concrete (original) (raw)
Related papers
Sustainable concrete: Building a greener future
Journal of Cleaner Production, 2018
In an effort to reduce waste and engage in more sustainable construction, this research focuses on the development of a cost-competitive, environmentally-friendly geopolymer concrete mixture that offers structural benefits relative to ordinary Portland cement (OPC), uses fly ash, a toxic waste byproduct as a raw material, and reduces the amount of CO 2 emitted during production of the concrete. The production of OPC, the current standard in concrete, relies on a high amount of energy, and as a result accounts for 7% of CO 2 emissions worldwide. Production of OPC is expected to increase 4-fold over the next 30 years, posing significant environmental risk. While numerous studies have examined the use of geopolymer concrete as a more sustainable construction material, concerns about the cost and environmental impact are obstacles against widespread production and market adoption. The new mix designs proposed herein result in up to a 50% decrease in the cost of geopolymer concrete, making this sustainable alternative a viable option relative to traditional concrete. In addition, the production of the proposed mixtures requires less than 50% of the fuel usage (thermal energy) required for OPC, decreasing CO 2 emissions. The proposed mixtures not only reduce environmental impact, but they also offer improved performance, which may appeal to many concrete manufacturers. While the proposed alternative to Portland cement is suitable for most applications, it is posited that those firms interested in pursuing sustainable construction may be most inclined to adopt the proposed mixture in order to meet their sustainability goals.
Concrete as a Sustainable Construction Material
2017
Sustainable concrete is nowadays one of the biggest challenges in the construction industry. Performance-based specifications for concrete can materially help meet this new challenge while supporting the concept of “sustainable construction”. Concrete can be found in almost every building structure, be it a pavement, a bridge, a house, a tunnel or a dam. Scholars nowadays are researching the best balanced mix in concrete in order to diminish its environmental impact, especially the cement component which is known for its high carbon emissions. This paper describes concrete durability and outlines what project specifications will significantly influence concrete performance, including its environmental impacts. The paper argues that, despite the sustainability of concrete, concerted efforts on the part of scientists and engineers are still necessary to improve the design of concrete in order to ensure their expected sustainable quality and reliability.
An Economic and Embodied Energy Comparison of Geo-polymer, Blended Cement and Traditional Concretes
As worldwide awareness and concern over increased carbon emissions and its direct impact over global climate change increases, there is intense pressure over all industries to reduce their emissions. The backbone of the construction industry is concrete, which is widely regarded as a high energy material. Some of the proposed alternatives are Blended Cement and Geo-polymer Concretes that utilize industrial wastes such as fly ash and slag. This paper aims at quantifying the merits and demerits of traditional, geo-polymer and blended cement concretes in terms of economic and energy reduction in Bangalore City.
Concrete: An eco material that needs to be improved
Journal of the European Ceramic Society, 2012
Concrete is the largest volume material used by man and is irreplaceable for innumerable large infrastructure developments. From the point of view of natural resources, ecology and economy, it is virtually impossible to imagine substituting concrete by any other material. However, because of the large volumes used, its total energy and CO 2 footprint is important. This material therefore needs to be improved and small steps can have a big impact, once again because of the large volumes involved. This review paper examines some of the routes that may be followed to further improve the environmental performance of concrete.
The use of concrete is associated with immense negative environmental impacts. More than 50 billion tonnes of aggregates are extracted annually for use in concrete, which presents high risks of depleting natural resources. Moreover, concrete has an embodied carbon footprint of 350 kg eq CO2/m3 on average of which 90% is attributable to the production of ordinary Portland cement (OPC). Although this is less than that of steel and most polymers per unit mass, the intensive use of concrete results in an alarming 7% share of the global carbon emissions. Therefore, increasing interest is being directed towards producing sustainable concrete. Conducting a Life cycle assessment (LCA) is a widely accepted tool to assess and compare the acclaimed environmental gains of these sustainable concrete types, while calculating the base line cost of each of these mixes could suffice for economic comparisons. However, sustainability is a multifaceted concept and in order to validate the sustainable o...
Site trials of concrete with a very low carbon footprint
2007
This paper reports on six site trials of sustainable concrete mixtures. The first three were concrete barriers for landfill, the fourth was a trench fill and the fifth and six were roads and car parks. The methods and mixtures evolved from moderately conventional designs containing ashes and slags and some cement which were blended at the plant to a super-sulphated pre-blended powder containing waste plasterboard and no cement. The strengths were not as high as a typical structural concrete but were fully adequate for each application. The paper concludes that while the technical viability of each mix was demonstrated, problems with insurance, capital funding, and environmental regulators have prevented their wider application
Environmentally-friendly concretes for sustainable building
The Sustainable City VII, 2012
The concept of sustainable development includes the judicious use of natural resources, which in some areas are rapidly depleting, achieved by using industrial by-products and thereby reducing materials waste. In addition, it is necessary to reduce energy consumption that is associated with CO 2 and other greenhouse gas emissions. The production of Portland cement also releases large amounts of CO 2 into the atmosphere. For this reason supplementary cementitious materials are being used in concrete: one of these materials is fly ash, which is a by-product of thermal power generation. Fly ash exhibits pozzolanic activity, and, if not used, has to be disposed of in landfills at a considerable cost. The use of other non-renewable resources, such as virgin aggregates, also needs to be reduced by recycling rubble from demolished buildings, processed in such a way that they can be used to replace virgin fine and coarse aggregate in concrete. This replacement also allows for reduction in the volume of materials disposed of in landfills. According to the concept of sustainable development, the environmental load of a building must be evaluated throughout its life cycle, from design to construction, maintenance or repair, demolition, and rubble disposal. Therefore, from a holistic point of view, sustainable construction means designing a reinforced concrete structure with appropriate durability during a specified service life. This paper discusses the effect of partial and full replacement of natural aggregates by recycled concrete aggregates (RCA) in a fly ash concrete. Engineering properties and durability performance have been examined for mixtures designed with various proportions of the RCA by mass. Results obtained showed that while incorporating high RCA amount could lower concrete performance, the combined use of RCA and fly ash could allow us to achieve adequate engineering properties and durability.
Sustainable High Performance Concrete Buildings
A recent research project using whole-building energy simulation showed that the effect of thermal mass in concrete framed buildings, combined with thermal improvements to the building envelopes, lowers energy cost up to 23% relative to a baseline steel framed building with EIFS (exterior insulation finishing system) ]. This energy savings qualifies for up to four points (Energy and Atmosphere Credit 1: Optimize Energy Performance). As of June 2007, all LEED projects are required to achieve at least two points under Optimize Energy Performance. The results of the research project provide in-depth information on potential energy savings in mid-rise commercial buildings.