مقاله انگلیسی انتشار دی اکسید کربن متعادل و تحلیل هزینه بتن نرم خود متراکم سبز
Abstract
Introduction
Materials and Methods
Results and Discussion
Conclusions
References
Abstract
Global warming and climate changes are the major environmental challenges globally. With CO2 emission being one of the main greenhouse gases emitted to the environment, and cement and concrete production amounting to about 10% of the global CO2 emission, there is a need for the construction industry to utilize an environmentally sustainable material as an alternative to cement. This study analyzed the cost, CO2 emission and strength properties of green self-compacting concrete (SCC) ternary blend containing fly ash, calcium carbide residue (CCR), and crumb rubber (CR) as a replacement material by volume of cement, cementitious material, and fine aggregate, respectively. Cement was replaced with fly ash at 0% and 40% by volume. CCR was used as a replacement at 5% and 10% by volume of cementitious materials, CR replaced fine aggregate in proportions of 10% and 20% by volume. The result indicated that the mix with 0% fly ash and 20% CR replacement of fine aggregate was the most expensive and had the highest CO2 emission. However, the mix with 10% CR, 40% fly ash, and 10% CCR had the lowest CO2 emission and was therefore the greenest SCC mix. The 28-day maximum compressive strength of 45 MPa was achieved in a mix with 0% CR, 0% fly ash, and 10% CCR, while the utmost 28-day splitting tensile strength of 4.1 MPa was achieved with a mix with 10% CR, 0% fly ash, and 5% CCR, and the highest flexural strength at 28 days was 6.7 MPa and was also obtained in a mix with 0% CR, 0% fly ash, and 5% CCR. In conclusion, a green SCC can be produced by substituting 40% cement with fly ash, 10% fine aggregate with CR, and 10% CCR as a replacement by volume of cementitious material, which is highly affordable and has an acceptable strength as recommended for conventional SCC.
Introduction
Climate change has emerged as a major environmental concern. Environmental sustainability is the major challenge of the construction industry, and several measures have recently been taken to overcome excess CO2 emission and greenhouse gas emissions associated with cement and concrete production. About 30 billion tons of concrete is consumed annually all over the world. Previously, the production of one ton of concrete generated about 0.5 to 0.6 tons of CO2. However, in 2019, the CO2 generated from concrete production reached 72.5 kg CO2/ton.Compared to forty years ago, the quantity of CO2 generated from concrete production has tripled due to the increase in demand of concretecompared to other construction materials [1]. Cement production alone accounts for 8% of the world CO2 emission generated as a result of human activity [2]. Cement production emits more carbon; the process entails heating a combination of limestone and clay in a kiln at a very high temperature of 1400 ◦C using fossil fuel, although the amount of CO2 generated is a measure of different factors such as the production material used, cement kin type, and the fuel burned [3].