Abstract:
The construction sector is rapidly growing over time, leading to an increasing demand
for materials used in this sector. One of the essential construction materials was
concrete, which was conventionally made using aggregate and binders.
River sand was predominantly used as fine aggregate in concrete mixtures. The
utilization of Natural River sand in concrete production depletes the natural resource of
sand and increases cost due to the shortage of sand in Jimma town.
This study was conducted to investigate the use of manufactured sand as a substitution for
natural river sand in C-25 concrete production. Natural river sand and manufactured
sand samples to be used in the concrete mixes were collected, their physical and chemical
properties (alkali silica reactivity) properties were studied, presented and evaluated
using, table, chart and picture.
According to the experimental results, the alkali silica reaction did not expand more than
0.1% after 14 days ‘of immersion in a NaOH solution in a water bath; therefore,
manufactured sand exhibited non-silica reactivity.
Five different concrete mixes were prepared for C-25 concrete strength, with a water to
cement ratio of 0.5 for both natural river sand and manufactured sand.
Based on the laboratory test results full substitution of natural river sand compared with
manufactured sand, yielded a mean compressive strength of 21.11Mpa at 7days and
32.61 Mpa at 28 days, while the mean, flexural strength at 28 days was 5.67Mpa, meeting
the requirements for C-25 grade of concrete. Furthermore, the cost of producing fine
aggregate from manufactured sand was 3,500 ETB per cubic meter, compared to the cost
of natural river sand from Jimma town, which ranged from 5,000 to 5,625 ETB per cubic
meter. Therefore, manufactured sand was less expensive than natural river sand.
In general, based on the all laboratory test results, manufactured sand was meets the
standard specification limits. Therefore, the construction sector should promote the use of
manufactured sand as a substitute for natural river sand due to Manufactured sand offers
greater economic benefits compared to river sand and can be effectively used in
construction projects in Jimma town.
