Rammed Concrete with Recycled Fine Aggregates

Abstract

The debris from the demolition of buildings, mainly concrete rubble, represents such a significant proportion of global waste. In the European Union, the construction industry generates about 850 million tons of construction and demolition wastes per year, and this amount causes a bad impact on the environment. Recycling fine aggregates as substitution of natural sands can be interested because it reduces the depletion of natural mineral resources and the amount of wastes being landfilled. Therefore, this use also can be advantageous for environmental and economic aspects in the construction sector. The objective of this research is to study the main physical and mechanical properties of rammed concrete incorporating recycled fine aggregates and using rammed earth method. The influence of the composition and curing conditions on those properties will also be investigated. Given that little is known about the properties of the recycled fine aggregates used, thoroughly characterizing them is also an objective of this work. The determination of the main physical and mechanical properties of rammed concrete was made by using experimental work on calculating the density and testing compressive strength. The recycled fine aggregates characterization is conducted according to the standards. The results show that increasing the cement content leads, logically, to better mechanical performances with a higher density and higher compressive strength. The study also shows that there is an optimum value of the water content between 5% and 15%. Lastly, it shows that using pretreated (cleaned) recycled fine aggregates leads to better mechanical performances which could allow a lower cement content for masonry uses. The rammed concrete material incorporating recycled fine aggregates is comparable to classical concrete block and cellular concrete block in terms of optimum strength capacity. Therefore, the rammed concrete is recommended to be implemented in masonry construction.