Abstract:
Some environmental problems are industrial wastes and cement production, causing a
high release of gas emissions affecting the environment. Cement plays a great role in the
expensive construction industry worldwide. This study aims to find out a more
economical material locally. Thus, an experiment partially replaced Ordinary Portland
Cement (OPC) with calcined Montmorillonite clay powder and waste khat husk ash. It's
known that Montmorillonite expands considerably more than the other clay due to water
penetrating the interlayer molecular spaces and concomitant adsorption, a material
content in expansive soil. Most of its soils are composed of expansive in Ambo town,
where the samples are extracted for Montmorillonite content determination. On the other
hand, the wastage quantity of khat husk was collected from other places.
The focus of this study is the usage of calcined two materials like a waste of khat husk and
Montmorillonite clay powder to partially replace the OPC to be used as modified
materials in normal concrete production. The MMT clay and KHA sample were collected
from Hachalu Hundessa Campus (TP1) and Buno Bedele Zone, respectively. The average
required to calcine of MMT clay was performed at 8000C by using a muffle furnace,
ground to the fineness of 150 μm, and its chemical composition was investigated, while
KHA was burned up to changes to ash. The proportions by weight was applied for the
OPC, Calcined MMT clay powder and Waste Khat Hush Ash as follows: Based
Proportion-A (100%: 0%: 0%); P-B (85%:10%:5%); P-C (75%:20%:5%); P-D
(65%:30%:5%); P-E (55%:40%:5%) and P-F (45%:50%:5%).
The production of concrete for C-25 Grade mix design was performed based on
standards and by following the ASTM manual, ERA manual, and the ACI code to evaluate
the strengths of concrete. The calcined materials were tested based on ASTM C618-5 to
evaluate the Chemical compounds at different temperatures, the highest value that was
obtained from the sum of the main components such as SiO2, Fe2O3, and Al2O3 more
than 70% was considered for the evaluation of the strength and durability of the concrete.
A 25mm maximum size of aggregates was used for the experiments.
Similarly, when partially replacing OPC with Calcined of MMT clay powder and KHA on
OPC properties such as consistency and setting time had remained within the acceptable
limits as per ASTM C 191 Standard Specifications. Likewise, the test results of
compressive, flexural tensile, and the split tensile strengths indicated a gradual decrease
from the control specimen during the amount increase of the replacement made. Hence,
the optimum amount of calcined MMT clay powder and Waste of KHA indicated up to
15% P-B (85% OPC, 10%CMMT, and 5%KHA) by weight to replace Ordinary Portland
Cement (OPC) content in normal concrete mix production.
