Greener Pervious Concrete Incorporating Surface Modified Activated Carbon

Concrete is the most-used construction material in the world and its production is an energy and emission intensive industry as it contributes 5% of the global CO₂ emission. Some of this carbon dioxide emissions are absorbed by the hardened concrete itself when the surrounded atmospheric carbon dioxide reacts with the hydration products of concrete in a naturally-occurring reaction known as carbonation. Concrete carbonation in its most optimistic values doesn’t compensate more than 30% of the CO₂ emissions released during concrete manufacturing. Therefore, this study aims at developing an environmentally friendly pervious concrete by incorporating an effective carbon sink within the concrete matrix in order to achieve a higher CO₂ sequestration rate. Activated carbon is a well-known adsorbent material that has been employed intensively for water contamination and air pollution removal. Therefore, it is utilized as a carbon sink in this study. To optimize the work of activated carbon in terms of CO₂ sequestration, it was modified by the least possible energy techniques by a series of modifying chemicals that have been proved to enhance the CO₂ sequestration such as NaOH, metal nitrates and Ammonia hydroxide. The modified activated carbon will replace 5%, previously-experimentally specified amount of the concrete fine aggregate. The effect of the activated carbon incorporation on the fresh and hardened concrete properties such as workability, strength and permeability will be investigated. In addition, the quantity of CO₂ sequestered by the previous concrete will be assessed via gas flow reactor system. Preliminary results show an increased sequestration of CO₂ due to the activated carbon incorporation while the concrete strength and permeability are hardly affected. Simple calculations reveal that structures made of activated carbon-pervious concrete might mitigate the problem of increasing CO₂ concentrations in the atmosphere.