Abstract:
The rate of consumption of natural aggregate increase as the demand for highway
construction materials increase and landfills fill up, interest in recycling solid wastes
such as demolished concrete and marble waste as conventional aggregate. Using wastes
are important to reduce natural aggregate consumption rate and to minimize pollution.
Solid wastes that have been considered as aggregate for base course include mineral
wastes from mining and mineral processing known as marble waste aggregate and
municipal wastes include commercial or household known as recycled concrete
aggregate. Using these wastes also enhance some properties of the pavement, hence the
aim of this study is to evaluate the suitability of recycled concrete and marble wastes as
conventional aggregates for base course material. Sampling population were recycled
concrete, marble wastes and suchlike solid wastes materials. Samples of recycled
concrete and marble waste were collected from Addis Ababa city, demolished Samsung
building and Ethiopian Marble Processing Enterprise, respectively. Purposive sampling
techniques and experimental sampling design were used in this study. Laboratory tests
were conducted to determine engineering properties such as gradation, specific gravity
and water absorption, California bearing ratio (CBR), aggregate crushing value (ACV),
aggregate impact value (AIV), loss Angeles abrasion value (LAV), plasticity, angularity,
flakiness and elongation index of recycled concrete and marble wastes. To achieve these
blend (0:100, 20:80, 50:50, 80:20 and 100:0)RCA and CA as well blend (0:100, 20:80,
50:50, 80:20, and 100:20) MWA and CA were conducted. Blend 80:20 RCA and CA
engineering properties obtained are Gs, W, FI, EI, ACV, AIV,LAA and CBR with
corresponding values of 2.21, 9.3%, 26.3, 21.8, 22.9, 15.9, and 15.5, 106% respectively
with well graded gradation. Blend 80:20 MWA and CA engineering properties obtained
are Gs, W, FI, EI, ACV, AIV,LAA and CBR with corresponding values of 2.68, 0.57%,
22.4, 17.4, 24.9, 16.2, and 19.7, 99%, respectively with well graded gradation. The
finding of the study shows that both materials can be as conventional aggregates for base
course. However, further research has needed particularly on long term field
performance of both materials.
