An appraisal of the quality of sandcrete blocks used for construction in Lagos metropolis

Sandcrete blocks have been in use in many parts of the world for a very long time. The prominence of sandcrete blocks as part of the local building materials that make up the wall units in a building or any construction work cannot be underestimated because houses are mostly built of blocks. This paper examines the quality of machine-vibrated hollow sandcrete blocks used on construction sites in Lagos metropolis. A total of sixty (60) units of machine-vibrated sandcrete blocks were sampled from ten (10) manufacturers within Lagos Mainland. Three (3) samples of 450mm x 225mm x 225mm blocks and another three (3) of 450mm x 150mm x 225mm blocks were selected from each of the 10 manufacturers to make the total of 60 blocks. Also, a total of forty (40) units of machine-vibrated sandcrete blocks were produced based on the requirements of the NIS 87:2004 standards for sandcrete blocks. The blocks obtained from manufacturers as well as those produced were tested to determine their quality in terms of three parameters which were the compressive strength, density and dimensional tolerance. The results obtained revealed that the compressive strength of the blocks obtained from manufacturers ranged from 0.21N/mm2 to 1.26N/mm2 for 225mm wide blocks and from 0.28N/mm2 to 0.95N/mm2 for 150mm wide blocks which are far below the minimum NIS requirements of 3.45N/mm2 and 2.5N/mm2 respectively. The densities of these blocks were found to be satisfactory with the requirements of the standard while the dimensions were inaccurate in terms of web thicknesses. It was recommended that the regulatory bodies should be empowered to control production processes and implement effective strategies such as mobile testing to ascertain the quality of sandcrete blocks

Geologising urban political ecology (UPE): the urbanisation of sand in Accra, Ghana

This paper makes a call for an urban political ecology (UPE) which engages more extensively with Earth’s geological formations. As a material at the centre of global urbanisation process, sand is offered as a geological entry point. The paper presents an analysis of the urbanisation of sand, or the ways in which sand is brought into the urban realm, grounding this reading in Accra—a growing city on Ghana’s Atlantic coast. Drawing from 14 months of ethnographic fieldwork, the paper charts the socio-natural politics through which sand is first unearthed from the edges of the city—an extractive processes otherwise known as “sand winning” in Ghana. By examining the forms of power which govern uneven revenue flows to communities, the displacement of farming groups, the widespread loss of farmland and a contested regime of governance, the analysis exposes the socio-natural politics through which the city’s geological baseline is first unearthed

Work-Related Fatalities Analysis Through Energy Source Recognition

Identification of hazards is the first step in accidents prevention. As hazards can be caused by different energy sources, the awareness of all the energy sources is key to identifying potential hazards and creating a safe environment. Accidents result from the interaction of energy, equipment, or materials, and one or more people, and the potential hazards associated with such interaction can be identified based on the energy sources recognition. A lack of understanding of the presence and magnitude of an energy source often results in an accident. As a result, it is important to identify highly innovative and effective hazard recognition strategies such as implementing techniques to avoid future accidents. This study analyzes fatalities and catastrophes data inspected by federal or state OSHA in the past 5 years. Modern machine learning techniques are deployed to power this study: 1) text mining for hazard report extraction and 2) multidimensional visualization for geospatial analysis. The outcome can assist personnel involved in high-risk activities to identify and control the potential hazards unique to each activity and job. As a result, energy sources posing dangers would be effectively managed and eliminated