In this study, influence of varied copper addition on the mechanical properties and corrosion characteristics of grey cast iron (GCI) was investigated. As-cast unalloyed and 0.035 wt. %, 0.65 wt. % 0.85 wt. % and 1.18 wt. % copper alloyed GCI samples were produced using rotary furnace. Chemical compositions of the samples were determined by Optical Emission Spectroscopy using ARL QuantoDeskSpectro analysis machine. Tensile and hardness measurements were made using INSTRON tensile testing machine- model 3369 and Universal Rockwell hardness testenr- model 8187LKV respectively. Samples’ characterization was done using Philips SEM (XL30 TMP). And electrochemical measurement was determined using AUTOLAB PGSTAT 204N instrument. From the results, the as-cast unalloyed, 0.035 wt. % and 0.85 wt. % and 1.18 wt. % Cu alloyed GCI samples revealed lamella graphite in pearlite matrix, short flake graphite in pearlitic-ferrritic matrix, Type A flake graphite in pearlitic-ferritic matrix and long flake graphite in ferritic-pearlitic matrix respectively. Tensile, hardness and elongation properties of the copper GCI samples ranked superior over the as-cast unalloyed GCI sample. Optimum tensile value 158.26 N/mm2 and hardness value 447.4 HRC were revealed by the 0.85 wt. % Cu, and optimum ductility value of 2.79% was revealed by the 1.18 wt. % Cu alloyed GCI sample. In general, copper alloyed GCI samples showed better corrosion resistance relative to the as-cast unalloyed GCI sample. The copper alloyed GCI samples showed better corrosion resistance relative as compared to the as-cast unalloyed GCI sample. Least corrosion rate of 0.0011297 mm/yr with polarization resistance of 174.58 Ω was revealed by the 0.85 wt. % Cu alloyed GCI sample. Hence, it is most suitable in application requiring high to moderate strength is marine environment.

This work characterizes the relationships between the intrinsic properties of sands and the parameters of four mathematical models that best simulate the experimental curves and geotechnical properties of sands used in construction. Origin.Pro.2019" software was used to smooth the grading curves, define the parameters of the mathematical models and link them to the geotechnical data. To achieve this objective, the correlations between the intrinsic properties of the sands are developed using mathematical models with the highest coefficient of determination (R2) and the lowest statistical coefficient (χ²). The correlations used are those with a coefficient of determination greater than or equal to 0.9. The results obtained show that the models used provide a good description of the experimental curves. The model parameters are correlated with the granulometric fractions and the geotechnical parameters. The evolution of the points expressing the parameters of the Gaussian and exponential models (A1, Xc, A, W, Yo) and the parameter (t1) as a function of seven randomly chosen geotechnical quantities, are polylinear and linear fits, respectively. This study is important for predicting a geotechnical quantity from a modelled grading curve, by solving the mathematical expressions of the models used.

The study was conducted to evaluate the experimental and theoretical shear strength of a simply supported reinforced concrete beam with and without shear reinforcement in accordance with Eurocode 2 design criteria. Fifteen (15) reinforced concrete beams of dimension 750mm x 150mm x 150mm reinforced with diameter 12mm size bars were cast at various reinforcement ratios (i.e. 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%), while preliminary and mechanical tests were conducted on the materials (i.e. cement, fine and coarse aggregate, and reinforcement bars) in accordance with relevant codes and standards. The outcome from the findings showed that the cement, fine aggregate and coarse aggregate used to cast the reinforced concrete beam were well graded and satisfies the requirement of code specification. More results showed that the average diameter of the reinforcement bars are 11.67mm, the mean tensile and ultimate strength of the reinforcement bars are 389.73N/mm2 and 640.80N/mm2 respectively, while the mean reinforcement steel elongation is 14.23% which mostly met code requirement indicating suitability of the reinforcement bars usage in concrete. Furthermore, the result from the findings showed that the Eurocode 2 (EC2) design criteria of beams without shear reinforcement were lower than the experimental value, while EC2 design criteria for beams with shear reinforcement was close to the experimental value.