Abstract:
In the present scenario, no construction activity can be imagined without concrete. To make
concrete using mix of three ingredients; aggregates, cement, and water are usual. Many
structures show premature and excessive deflection due to improper use of construction
material. The cost of material used in making concrete is also another important concern.
Therefore, the use of other additional materials in a certain prescribed proportion, known as
additives, to increase strength of concrete need attention this day. This study focused on
experimental investigation of the suitability of teff straw as an additional concrete material in
concrete mix.
The conventional mix had been designed for C-25 grade concrete having a target mean
strength of 28 MPa with a water-cement ratio of 0.5 and within a 20-50 mm slump range.
Cubical concrete unit samples of size 150×150×150 mm were prepared and tested for
compressive strength; cylinder of 150mm in diameter and 300mm in length were tested for split
tensile tests; 100 mm× 100 mm cross section with 500mm length prism were tested for flexure
strength. Percentage addition of teff straw fiber by weight of concrete had been tested for (M0
= 0.00 %, M1 = 0.15 %, M2 = 0.25 %, and M3 = 0.35%). The concrete has been casted and the
compressive strength, splits tensile strength and flexural strength tests at 7 and 28 days curing
periods were tested and compared against plain concrete.
Mean flexural strength of concrete with an addition of teff straw with M1, M2 and M3 addition
of teff straw by weight of concrete has shown an increment of 19.38%, 4.19% and 0.66%,
respectively. Compressive strength for M1 showed an increment of 17.08% and for M2 and M3
showed reduction by 11.51% and 7.87% respectively .While the split tensile strength showed
an increment of 5.28% and 0.30% for M1 and M3 respectively and 0.76% reduction for M2. On
the other hand, slump results for mix design M1, M2 and M3 addition of teff straw by weight of
concrete showed reduction effect by 20 %, 40% and 50% respectively. Finally, for the fresh
concrete densities, a slight reduction by 2.00%, 2.32%, and 2.84% has shown, respectively due
to volume addition of fresh concrete with teff straw
