Abstract:
Recent studies are focusing on ways of utilizing either industrial or agricultural wastes as
a source of raw materials for the construction industry around the world. This is used to
minimize the emission of CO2 during the manufacturing of cement. One of the agricultural
waste products is coffee husk which is found in large amounts in Ethiopia. This thesis
aims to characterize the physiochemical characterization of Coffee Husks Ash (CHA) by
using X-ray diffraction (XRD), Scanning electron microscope (SEM), and Fourier
Transforms Infrared Spectroscopy (FTIR) tests, and also the experiment were conducted
to determine the compressive, split tensile and flexural strength of the material and
durability tests were determined at replacement ratio of 0%, 5%, 10%, 15%, 20% and
25% by volume of cement.
The result have shown that up 10% replacement, the XRD, FTIR and SEM showed that
crystalline material decreases, the peaks are sharp and the dense microstructure
respectively, whereas, the replacement percent increases above 10%, the crystalline
material increases, the peak intensity disappeared, and also the micro pores or air void
are increases, which may lead to decreasing the strength of concrete.
In the case of compressive, flexural and split tensile strength of concrete, there has been
increment in 7.2%, 4.5% and 8.08% respectively at 5% CHA replacement and also the
compressive strength up to 10% replacement more than the expected target strength value
at 28days, after10% CHA replacement the compressive strength value become decreases.
Water absorption and sulfate attack at 5% of partially replaced concrete are shown an
improvement in the durability of concrete.
