This paper shows experimentally effect of gravel beds to reduce erosion of soil downstream of submerged hydraulic jumps by using a physical model, gravel beds are employed downstream of radial gate to dissipate the energy and to control the erodibility of cohesionless soils. Two different types of gravel were considered, natural particle with graded grain sizes, and non-uniform big grain sizes, a state of smooth bed was included to estimate the influence of gravel beds on the scour hole dimensions. A preliminary comparison of the incipient motion values shows that granular soils downstream gravel bed have a smaller free surface flow erosion than the granular soils downstream smooth bed. Additional comparison of the experimental data incipient motion criteria also suggests that decrease void ratio for gravel bed leads to minimize erosion the soil. The gravel beds reduce the maximum scour hole by rate from 47% to 66% in comparing with the smooth bed.

The indiscriminate disposal of animal waste in the environment has led to the search for solution by recycling these wastes, which includes the use of animal bone waste in the construction industry, as a partial replacement of cement in concrete. The aim of this project is to study the properties of the concrete by partial replacement of cement with animal bone powder. The bone powder is replacing cement partially by weight in mix proportion (3%, 6%, 9%, 12% and 15%). The objectives of this research are to protect the environment from the harmful effects of animal wastes by using animal bone powder in concrete as a partial replacement for cement, to study the possibility of using animal bone powder in the concrete mix and to investigate the effect of animal bone powder on the compressive and the spilt tensile strength of the concrete mixture. Conduct preliminary tests on the basic materials, including fine aggregate, coarse aggregate and cement. The mix design was developed for C30 grade concrete using the ACI method. The mix proportion used is 1: 1.67: 2.34 with water cement ratio of 0.5. Cube samples with dimension of 150mm×150mmx150mm and cylinder samples of 150mm diameter and 300mm height respectively were used to prepare concrete mix. Concrete samples were cast during this study replacing the cement with the animal bone powder. A total of 18 cubes and 18 cylinders were cast in this study and the samples were cured in the water tank for 28 days under normal conditions. Cube samples were tested for compressive strength and cylinder samples for split test in a UTM. The research has shown that the use of animal bone powder as a partial replacement of cement in concrete can affect the properties of the concrete. The results of the experiments showed an increase in compressive strength and split tensile strength when compared with the results of the normal mix however; as the bone powder content increased a reduction in the workability of the concrete was observed and recorded. Furthermore, the results showed the optimal replacement percentage of BP in concrete is 6 percent with compressive strength of 36.2 N/mm2 when compared with other replacement ratios. Therefore, from an environmental and technical perspective, there is an opportunity to utilize waste animal bones in concrete for construction applications.