Abstract:
Disposal of bauxite tailings in Ghana and globally is not properly managed and leads to
environmental degradation. There is possibility for their recycle to facilitate proper disposal, one
way is to partially replace sand with bauxite tailings in building blocks. A study was carried out
on cement composite blocks made from sand and bauxite tailings/residue, a mining by-product at
varying levels from 10% to 50% with incremental level of 10%. Composite blocks were produced
to dimensions of 150mm × 150mm × 150mm for the various replacement levels consisting of 0%,
10%, 20%, 30%, 40% and 50% by weight of sand. A total of 120 blocks were produced and
tested for their densities, compressive strengths, and resistance to abrasion and water absorption
after 28 day of curing. Results from the study showed that composite blocks with the bauxite
tailings replacing up to 20% of the sand content recorded the highest compression strength, lowest
abrasion loss with the least water permeability. Even though, there was a general decline in the
properties of the composite blocks with bauxite tailings replacement beyond 20%, blocks
produced satisfied the minimum requirements for blocks for wall construction. The compressive
strength of the composite blocks saw a significant decline from 15.907N/mm2 to 8.427N/mm2 as
the bauxite tailings content increased beyond 20% up to 50%. It was observed that there was a
systematic fall in the average dry densities of the blocks as the quantity of bauxite residue was
increased. Comparatively, the composite with B50 grade was 14.16% lesser dense than the control
block. It was evident that abrasion loss significantly increases as the quantity of bauxite residues
increases beyond 20% replacement in the composite blocks. The addition of bauxite tailing
content thus resulted in lower migration of water into the block (i e. lower permeability). A strong
correlation existed between the composite blocks produced from the different batches and the
properties of the blocks studied. The results indicate that at the replacement level of 20%, the
bauxite tailings have a good potential for use as a masonry material for wall construction.
Description:
A DISSERTATION/THESIS IN THE DEPARTMENT OF CONSTRUCTION
AND WOOD FACULTY OF TECHNICAL EDUCATION, SUBMITTED TO
THE SCHOOL OF GRADUATE STUDIES, UNIVERSITY OF EDUCATION,
WINNEBA IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR
AWARD OF THE MASTER OF PHILOSOPHY IN CONSTRUCTION
TECHNOLOGY DEGREE.
AUGUST 2014