The recycled concrete aggregate RCA was able to take the place of the vierge &
natural aggregate NA, embankments elected,to implement the base&subbase road layaers
and airports in many country of the world.furthermore, there is almost consensus by
a large
of reshershers and scholars about the possibility of using RCA in mix cement concrete for
non-structural elements .whil,the using of RCA in the hot mix asphalt HMA still under
discussion and debate, due its high porosity , high water absorption, and its heterogeneity
which reflected negatively on the mechanical and physical properties of the HMA
This research discusses stadying the possibility of using the recycled concrete
aggregates in hot mix asphalt HMA, for the implementation of the bas layer bituminous
road , by the application of the marshall tests on hot mixtures asphalts have ben prepared
using different ratios of recycled concrete aggregates.
The results of marshall testes showed that the HMA prepared with amount of
recycled concrete aggregates less than 50%,can be used to implement the base layer
bituminous road,according to the general terms and specifications book for road works and
bridges in the syrien arab republic.
The recycling of debris, is considered as one of the most important resources for
constructing base &subbase road layers in many countries.
There are two problems for RCA: first, the considerable size it takes up when
collected and second, its low
technical properties. The second problem appears in
countries which don't have natural quarries and they have to use RCA in certain fields
(concrete mixes, asphalt mixes, granular road layers).
This research discuses preparing RCA aggregates, by recycling the concrete waste,
which comes from Al-Sallima landfill, near to Damascus city. Then many tests are carried
out to study the effect of changing the aggregate's size on their mechanical & physical
properties, and also to study the possibility of using these aggregates in constructing base
&subbase road layers.
As a result, it has been found that we can use RCA for constructing unbound base
&subbase road layers, and the mechanical & physical properties of these RCA get better
when the aggregate's size gets smaller, except in Proctor test. In this test, Proctor density
and optimum moisture content get better when aggregate's size gets bigger.
