With the growing emphasis on sustainability, the construction industry is more interested in applying environmental friendly concrete in its construction projects. This paper developed model for predicting the 28th day flexural strength of laterite-quarry dust concrete using (5, 2) extreme vertices design of Minitab 17. Physical property test were conducted on the laterite and quarry dust and several trial mixes of concrete were carried out to determine the lower (Li) and upper bound (Ui) limit of each of the components. River sand was replaced with a maximum of 40% laterite and 60% quarry dust in the trial mixes. Several mix proportions were generated using the extreme vertices design. The design matrix consisted of fifteen (15) design points and seven (7) check points with replications of the vertices and the centroid, given a total of twenty eight (28) runs. Eighty four (84) numbers of laterite-quarry dust concrete beams of 600 x 150 x 150mm were prepared and tested for their flexural strength after 28 days of curing. A second degree polynomial was fitted to the data of the flexural strength test result and adequacy of the model was confirmed using the p-value, F statistics and normal probability plot. Several mix proportions were generated and their flexural strength obtained using the developed model. The minimum and maximum flexural strength predictable by the model are 2.44N/mm2 and 4.95N/mm2. The model can help predict the flexural strength of laterite-quarry dust concrete for both reinforced and non-reinforced concrete design for domestic and commercial constructions.

Index properties of soil forms part of the precondition for its use in civil engineering construction works. The neglect of it will give investors a wrong idea about the properties of the soil material. This research investigates the index properties of soils along jos-makurdi road in north central Nigeria. A trial pit was dug under four different bridges to a depth of 1m each and soil samples were collected by method of disturbed sampling and analyzed using the following tests: Moisture content test, Particle size distribution test, Atterberg limit test and Specific gravity test. All these tests were carried out according to procedure highlighted in BS1377 1990. By visual inspection Grey colours were observed of both soil sample SS1and SS2; while light brown and brownish colours were observed from SS3and SS4 respectively. The natural moisture content of the soil sample SS1, SS2, SS3 and SS4, are 6.56, 7.89. 52.52 And 54.72%. Using the unified soil classification system (USCS), the SS1 and SS2 were classified as well graded sand (SW) while SS3 as silt sand (SM) and SS4 was classified as clay sand (SC), respectively. The SS1 and SS2 were non-plastic while SS3 have liquid limit (LL) of 33.62%, plasticity index of 32.06% and linear shrinkage of 3.85%; and SS4 have liquid limit (LL) of 52.40%, plasticity index of 41.28% and linear shrinkage of 2.5%. The specific gravity (GS) obtained from the test results are 2.66, 2.65, 2.38 and 2.27, for SS1, SS2, SS3 and SS4 respectively. Based on the test results obtained from the study trial pits, SS1 and SS2 are well graded sand (SW) which is suitable for most engineering construction while silt sand (SM) and clay sand (SC) will require stabilasation or modification for possible use in engineering application. Based on these investigations, the index properties of the soil sample, SS1, SS2, SS3 and SS4 varies with the location.

The effective factor has the turn of M1>M2>M3 in robotic arm. It has too turn 0.5m/s, 5º/s> 0.3m/s, 8º/s> 0.1m/s, 11º/s within conditions. That says that the speed is larger than angular speed about its effect to torque. The biggest torque happens at 5 º/s and 0.5m/s in first robot arm which is 1800Nm. The least one is at 11 º/s and 0.1m/s in the third robot one which attains 9Nm. The turn of effective torque is small angular speed and hammer speed. When the angular speed arrives 3º/s and hammer speed attains 0.5m/s the 3000Nm torque may be formed.

Through modelling it is found that the torque value attains 4000Nm with arm and hammer speed of 0.6º/s and 0.05m/s respectively with including arm3 whilst the torque arrives 480Nm with 5º/s and the same hammer speed of 0.05m/s with kinetic energy of only hammer. The torque has been the least of 80Nm at 30º/s with one kinetic system. Meantime the one may be 620Nm at 4 º/s with two kinetic system. That means that the least torque is formed through the biggest speed and hammer kinetic system. For the cost declining the less torque may be adopted and for the security the bigger one may be chosen. In this paper the less one is a factor for the cost declining. It is found that the effect turn is angular speed being bigger than hammer speed. So we shall pay more attention to the former. The angular speed is smaller the torque is higher.