The mechanical properties of sandcrete block greatly influenced the durability of structures built from it. This study was carried out to assess the compressive strength of sandcrete blocks produced in two major developmental and rapidly urbanizing zones of Delta State, Nigeria. 150 and 225 mm sandcrete blocks were sampled from 18 blocks moulding factories in Ndokwa East and Ughelli North Local Government Areas of Delta State, Nigeria. Five sandcrete block was sampled from each block moulding factory, at the rate of 9 factories per Local Government Area. The compressive strength of the sampled blocks was determined in accordance with the ASTM International standards. The results of compressive strength test showed that the compressive strengths of the blocks, regardless of the block size ranged from 0.61 to 16.19 MPa. Analysis of the results revealed that apart from the customized blocks, the compressive strengths of all the other blocks fell below the Nigerian Industrial Standard (NIS) recommendations of 2.5 MPa for non-load bearing walls. The general poor quality of the sandcrete blocks is attributed particularly to the poor mix ratios adopted by the block producers which fell short of NIS recommendations. Thus, this study recommended that standard regulatory agencies should closely monitor all the block making factories in the state, to ensure that sandcrete blocks produced or brought into the state met NIS recommendations
This paper evaluated the influence of cassava effluent on the compressive strength of concrete for farm structures. Three sets of concrete cubes were produced with a concrete mix ratio of 1:2:4 (C 15) and a water to cement ratio (w c-1) of 0.5. The 1st set was produced with 100% fresh water (tap water). The 2nd set was produced with 75% partial replacement of the fresh water with fresh cassava effluent, while the 3rd set was produced with 75% partial replacement of the fresh water with old cassava effluent. The density, water absorption rate and compressive strength of the concrete cubes was tested in accordance with ASTM International standards, at the end of 7, 14, 21, 28 and 56 curing days. The results revealed that, the cassava effluent slightly increased the cubes density; but reduced their water absorption rate. The study further showed that, concrete produced with fresh cassava effluent, developed the highest compressive strength (29.57 MPa) at the end of the 56th curing day. In contrast, concrete produced with old cassava effluent developed the lowest compressive strength (24.43 MPa) at day 56, which was lower than the compressive strength of 27.18 MPa developed by the concrete produced with fresh water (also at day 56). In addition, the cassava effluent retarded the initial rate of strength development, as such, increasing its prospect as an organic concrete admixture. This study will be helpful in mitigating the harmful effects of cassava effluent in the environment, since it can be utilized in concrete production.
Soil heavy metals pollution is a major global threat, because of its impact to plants, animals, and the soil geotechnical properties. Geostatistical method was used to investigate the spatial distributions of aluminum and lead within a section of the Delta State University of Science and Technology, Ozoro, Nigeria. A total area of 1 km2 (100 hectares) was covered within the school environment. Twenty -five (25) topsoil samples were collected, at the end of the dry season (March 2021); when the water table in the study area was very low. The lead and aluminum concentrations of the 25 samples were measured by using the Association of Official Analytical Chemists (AOAC) approved methods. Using a geostatistical tool, the lead and aluminum concentrations and distribution in the soil were plotted on predication maps. The maps revealed irregular spatial distributions of lead and aluminum ions within the study area. The lead concentration was highest at the North-central region of the study area; while lead concentration was lowest at the Eastern region of the study area. In terms of the aluminum metal, the highest aluminum concentration was observed in the North eastern region; while aluminum concentration was lowest at the South western region. Data obtained from this study will be useful for agricultural and civil engineering purposes, mainly in the area of decision-making.
Concrete with appreciable compressive strength is required for building constructions, to minimize the occurrence of building failures. Determination of the compressive strength of in-situ concrete produced in Isoko region of Nigeria was carried in this study. Concrete used for the construction of foundation wall footings for twenty residential buildings were sampled in the study. The compressive strength of the in-situ concrete was determined in accordance with ASTM standards. Field survey depicted that most (60%) of the concrete quality production process fell below the approved standard of 17 MPa, for residential buildings. The findings of the study revealed that the compressive strength of the in-situ concrete varied between 8.1 MPa and 19.8 MPa. Furthermore, the result of the compressive strength test showed that most (70%) of the in-situ concrete failed to meet the NIS recommended standard. Also, it was observed from the findings that proportionally, the concrete produced by conventional building/construction engineers was of a higher compressive strength, when compared to the concrete produced solely by masons. Based on observations obtained result obtained from this study, it is recommended that the Government should constantly educate building sites managers, on the need to adhere strictly to standard recommendations, in order to improve the quality of in-situ concretes produced.
Traffic emissions are one of the biggest drivers of heavy metals contamination in ecosystem; therefore vehicular traffic has become a major source of worry. The purpose of this study was to determine the influence of automobile emissions on roadside soil. Soil specimens were taken from two significant locations in Delta State, Nigeria, along a major highway. Soil samples were collected at four different distances from the roadside (1 m, 10 m, 20 m, and 30 m) at each location. The amounts of heavy metals (copper, zinc, lead, and cadmium) in soil samples were determined using established techniques. The chemical analysis results revealed that heavy metal concentrations in roadside soil samples were substantially (p ≤0.05) higher than in the control soil sample. This revealed that the quantities of heavy metals in the soil samples were related to road traffic activity. The results also revealed that the amounts of heavy metals in roadside soil reduced as the distance between the test point and the highway increased. According to the findings, the copper, zinc, and lead contents in the soil samples were lower than the World Health Organization's maximum tolerated values (WHO). However, the results revealed that the cadmium concentration was frequently higher than the WHO's maximum tolerated limit. The findings also found that heavy metal pollution in roadside soils along the route ranged from minor to significant (degree). Furthermore, the concentration and pollution level at sampling position A were higher than those at sampling location B, which can be attributable to the fluctuation in the volume and concentration of traffic emissions received at each sampling point. To avoid the excessive accumulation of dangerous heavy metals in the ecosystem, our findings highlight the necessity to decongest vehicular traffic along major highways throughout the country.
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