The need to reduce the increasing demand for crushed granite as coarse aggregate as well as the need to safeguard the environment from degradation has given rise to various researches on alternative materials that can serve the same purpose while minimizing environment hazard. This study assessed the suitability of waste ceramic tiles as coarse aggregate in concrete and to ascertain its strength against normal crushed granite. Crushed waste ceramic tiles from ceramic manufacturing industries and construction sites were mixed with crushed granite stones as partial replacement for concrete. A mix ratio of 1: 1.11: 2.72 (cement: sand: stones) for nominal C30 concrete was produced with (0, 10, 20, 30, 40, 50 and 100) percent volume ceramic waste aggregate replacement for crushed granite at a constant water-cement ratio of 0.5. Concrete cubes of size 150mm x 150mm x 150mm were produced and tested for 7 days and 28 days compressive strength, density and water absorption. The results revealed the viability of waste ceramic tiles as partial replacement for crushed granite in concrete production, but the partial replacement should not exceed 20% as recommended maximum for structural concrete. This mode of recycling ceramic waste could positively sustain the environment.

In view of the ever depletion of sources of construction materials, there is a need to explore the feasibility of using palm kernel shells and glass as replacements for natural crushed aggregates in Portland cement concrete. Concrete specimens produced with 25% palm kernel shells as partial replacement of coarse aggregate and varying percentages of recycled glass powder as pozzolana were tested for their workability, compressive strength, and tensile strength. Six different concrete specimens were prepared using recycled glass powder contents of 0%, 5%, 10%, 15%, 20%, and 25% in 1:2:4 concrete mix for compressive strength and split tensile strength. Palm kernel shells and recycled glass powder pozzolana were respectively found to be good replacements for natural aggregates and cement in concrete production. With regard to the workability of the concrete, it was found that palm kernel shells and recycled glass powder concrete had similar characteristics to conventional concrete mixes. Partially replaced palm kernel shells and recycled glass powder showed a strength variation of about 15% from natural crushed aggregate concrete. It is recommended that glass powder pozzolana in 25% palm kernel shell aggregate concrete should not exceed 15%.

A number of research seeking alternative materials to augment normal coarse aggregate to reduce overreliance on granite while saving the environment is on the rise.  This study assessed the workability, water absorption and density of concrete with waste ceramic tiles as partial replacement for crushed granite coarse aggregate. Crushed waste ceramic tiles from ceramic manufacturing industries and construction sites were blended with crushed granite for concrete production. A mix ratio 1: 1.11: 2.72 (cement: sand: coarse) for nominal C30 concrete was produced with (0, 10, 20, 30, 40, 50 and 100) percent volume ceramic waste replacement for crushed granite at constant water-cement ratio of 0.5 to produce concrete cubes and cured for 7 and 28 days. Tests conducted revealed concrete workability and density decreased with increasing ceramic waste while water absorption increased with increasing ceramic waste but not above acceptable limits. However, use of waste ceramic tiles as partial replacement for crushed granite in concrete is encouraged, but not exceeding 20% maximum for structural concrete. This mode of recycling ceramic waste could positively promote green construction for sustained environment; hence, it should be encouraged with conditional limitation and further research of its use.

This study was conducted to examine the structural behavior of concrete beams reinforced with local steel bars available in Ghana. The concrete was prepared from conventional materials of ordinary Portland-limestone cement, pit sand and granitic stones. Steel bars of sizes 12mm, 10mm, and 8mm from different millers used to reinforce the concrete beams were tested to study the stress-strain relationship of the bars. The main reinforcing steel bars in the concrete beams comprised 12mm high tensile and 12mm mild steel bars produced by four different companies. The four companies from which these steel bars were obtained are Ferro Fabric Limited (FFL), United Steel Company (USC), Sentuo Steel Limited (STS) and Fabrimetal (FAB). The specific objectives of this study were to determine the actual strength and sizes of steel bars used to reinforce concrete (steel bars of nominal sizes 12mm, 10mm and 8mm from different millers), to study the stress- strain relationship of the bars, to study the ultimate limit state characteristics of beams reinforced with different bars and to investigate the deformational behaviour of concrete beams reinforced with different bars (i.e., cracking, deflection).  Data collected were analyzed using theoretical and experimental approaches. The experimental results confirmed theoretical analysis that indicated that governing failure loads of the beams were due to steel yielding first with the exception of one beam in which the governing failure load was by shear. On average the experimental cracking and failure loads in the beams reinforced with high-yield steel bars were slightly higher than the theoretical loads, while they were observed to be slightly lower in the beams reinforced with mild steel bars. With regard to cracking, the beam reinforced with FFL ribbed mild steel developed the highest number of cracks at failure which represent a very good bonding between steel and concrete as compared to the other companies. Beams reinforced with FAB high-yield steel had the highest failure load as compared to the other steels. It is important to ensure standardization of the rebars in the Ghanaian market such as the size of the bar, the rib spacing, and the rib height through the dissemination of information to stakeholders including structural and material engineering manufacturing companies and contractors.