Cost Optimization of Sandcrete Blocks through Partial Replacement of Sand with Lateritic Soil

This work finds a way in which lateritic soil within Ota, Ogun State of Nigeria could be used in the production of hollow sandcrete blocks. This replacement is intended to develop more economic sandcrete blocks since the cost of lateritic soil in Ota is much less than the cost of the conventional fine aggregate used in the production of sandcrete blocks without compromising the intergrity of the blocks. It was deduced from literatures that inclusion of lateritic soil in sandcrete block production results in a lesser quality blocks. However, this work found the maximum permissible replacement that still makes the blocks to be within the recommended standard. The blocks were produced with each lateritic soil sample from different sources replacing sand in steps of ten percent to 60% and their compressive strengths determined and compared with that of a standard sandcrete block to check for the acceptable percentage replacement. In the compressive strength test, 72 numbers of 225 x 225 x 450mm hollow laterised sandcrete block sizes were produced, cured and crushed to determine their twenty-eight-day compressive strength. Cost analysis was performed discovered that the inclusion of the lateritic soil saves the cost of production by 11.89%. This percentage replacement can be recommended to the block moulding industries within Ota with a view to reducing the production costs of the blocks

RECYCLING FINE SANDCRETE BLOCK WASTE (FSBW) AS FINE AGGREGATE IN THE PRODUCTION OF SANDCRETE BLOCK

The study investigated the use of Fine Sandcrete Block Waste (FSBW) as fine aggregate in the production of sandcrete blocks with a view of controlling waste and decongesting block molding production sites. Standard sandcrete blocks of size 450mmX225mmX225mm were prepared from a mix ratio 1:6 (cement: fine aggregate) containing sand and FSBW as fine aggregates. The sand was partially replaced by FSBW in the mix within the range 0% - 90% in steps of 10%. The blocks were cured for 28 days and then tested for compressive strength. The physical properties of both the sand and FSBW were also determined. The results of the study revealed that the physical properties of FSBW compares favorably with those of conventional sand with the exception of water absorption. It further showed that the density and the compressive strength of the tested blocks decrease as the percentage replacement of sand with FSBW increases. The density of the blocks varied linearly with the compressive strength. Blocks prepared for mixes having 50% FSBW content or less were found to satisfy the minimum recommended compressive strength of 3.45N/mm2 (NIS 87:2000)

Performance of Build-operate-Transfer Projects: Risks' cost implications from professionals and concessionaires perspective

Determining cost implication of risk factors on performance of Build Operate Transfer (BOT) projects is a major focus of this study. One-hundred and seventeen structured questionnaires were used to collect information randomly from the respondents which made up of professionals such as Builder, Architect, Quantity surveyor and Civil engineer. Content analysis was carried out on the responses for validation; data were further analyzed with Mean Item Score using Risk Mean Index and validated with regression analysis. Meanwhile, the most common risk to all the projects executed are inflation, variation to works, change in government policy and fluctuating nature of foreign exchange with inflation being the highest on rating scale of 0.1 to 1.0 with corresponding cost implications and years. Against the background of the research outcome therefore, cost and time is used in this context as a model typifying the extent of risk implication experienced on the projects

COST AND TIME PERFORMANCE INFORMATION OF BUILDING PROJECTS IN DEVELOPING ECONOMY

The construction industry plays a very important role in nation development and in construction project delivery and timely provision of shelter and dwelling units for the masses. The aim of the study therefore is to study cost and time performance on building project in developing economy, with a view to finding ways of improving cost and time performance on building projects. Some of the developing in used in this context includes: Nigeria, Togo, Cameroun, and Ghana. A population size of 70 was selected, and a total sample size of 59 respondents was used in this study, with questionnaire distributed to construction professionals. Variables pertaining to the above listed targets were identified and incorporated into questionnaires as the primary source of data. The data was collated and analysed, using mean item score ranking, percentages and the use of descriptive statistics. It was discovered that variables like rising prices of building materials, inclusion of additional work as a result of clients’ request, deterioration in economic situation, were identified as the top causes of variation in construction project from developing countries. Also, cost, poor planning and scheduling, delay in payment approval for additional work, work suspension by client, were identified as top causes of time and cost variations. The study recommend among other things that: full consideration should be given to projects from inception to completion, adequate and effective consultancy services for clients, as well as strict follow up of programme of works by every contractor for a construction project

Effect of Nitric Acid Concentration on the Compressive Strength of Laterized Concrete

Laterized concrete is concrete in which some or all of the fine aggregates is from laterite. In this study, the effects of varying nitric acid concentrations (0%, 5%, 10%, 15%, and 20%), mix proportions (1:1:2, 1:1½:3), exposure period (28, 56, and 84 days) and percentage laterite content (0%, 25%, and 50%) on the compressive strength of laterized concrete were investigated. The tests were carried out with a view to simulating the performance of laterized concrete in contact with soluble nitrate-based substances. 100x100x100mm cubes of laterized concrete were cast and moist-cured for 28 days and the strength of concrete at this age was determined. The cubes were thereafter immersed in 0%, 5%, 10%, 15%, and 20% concentrations of nitric acid for a total of 84 days. Compressive strength tests were carried out at the end of 28 days, 56 days and 84 days of immersion. The results of the tests indicated that the compressive strength significantly reduces with increase in acid concentration, immersion period and laterite content. The effect of richness of mix on resistance of laterized concrete to the acidic aggression becomes more pronounced at the highest (50%) laterite content. Keyword: compressive strength, laterized concrete, nitric acid concentrations, percentage laterite content

Recycling fine sandcrete block waste (FSBW)as fine Aggregate in the production of sandcrete Block

The study investigated the use of Fine Sandcrete Block Waste (FSBW) as fine aggregate in the production of sandcrete blocks with a view of controlling waste and decongesting block molding production sites. Standard sandcrete blocks of size 450mmX225mmX225mm were prepared from a mix ratio 1:6 (cement: fine aggregate) containing sand and FSBW as fine aggregates. The sand was partially replaced by FSBW in the mix within the range 0% - 90% in steps of 10%. The blocks were cured for 28 days and then tested for compressive strength. The physical properties of both the sand and FSBW were also determined. The results of the study revealed that the physical properties of FSBW compares favorably with those of conventional sand with the exception of water absorption. It further showed that the density and the compressive strength of the tested blocks decrease as the percentage replacement of sand with FSBW increases. The density of the blocks varied linearly with the compressive strength. Blocks prepared for mixes having 50% FSBW content or less were found to satisfy the minimum recommended compressive strength of 3.45N/mm2 (NIS 87:2000)

COST AND TIME PERFORMANCE INFORMATION OF BUILDING PROJECTS IN DEVELOPING ECONOMY

The construction industry plays a very important role in nation development and in construction project delivery and timely provision of shelter and dwelling units for the masses. The aim of the study therefore is to study cost and time performance on building project in developing economy, with a view to finding ways of improving cost and time performance on building projects. Some of the developing in used in this context includes: Nigeria, Togo, Cameroun, and Ghana. A population size of 70 was selected, and a total sample size of 59 respondents was used in this study, with questionnaire distributed to construction professionals. Variables pertaining to the above listed targets were identified and incorporated into questionnaires as the primary source of data. The data was collated and analysed, using mean item score ranking, percentages and the use of descriptive statistics. It was discovered that variables like rising prices of building materials, inclusion of additional work as a result of clients’ request, deterioration in economic situation, were identified as the top causes of variation in construction project from developing countries. Also, cost, poor planning and scheduling, delay in payment approval for additional work, work suspension by client, were identified as top causes of time and cost variations. The study recommend among other things that: full consideration should be given to projects from inception to completion, adequate and effective consultancy services for clients, as well as strict follow up of programme of works by every contractor for a construction project

What Lenders Want from Mortgage Valuation Reports:A Survey of Nigeria Banks

For over a decade now, the Nigerian real estate industry has witnessed a steady but continuous growth as via the participatory activities of major private sector players both nationally and internationally. Hence, the need to urgently explore the requirements of valuation report users is eminent as the report serves as an important input to lenders' decision making. Surveying the existing twenty-two (22) Nigerian banks as prime users of valuation reports in the country, this study examines the need of these banks vis-a-vis the report content with a view to determine their needs and further improve on the quality of valuers’ reports. The needs of the banks were examined in accordance with the reporting format of Nigerian valuation reports. Using mean ranking coupled with the relative importance index (RII) methods, retrieved data were analysed and findings showed that lenders require more explicit details relating to salient aspects of the property market in valuation reports which include valuation calculations and uncertainty in valuation figures. The study concluded that the profession of estate surveyors and valuers should be mindful of the new expectation of their clients and try as much as possible to meet those expectations to retain the reliability of valuation reports in Nigeria

Effects of Climate Change on Built Environment in Lagos, Nigeria

Climate change has become one of the most exigent concerns of human race today. The effect of climate changes connected to human activities has become alarming since our ecosystem is not naturally adapting quickly to this phenomenon that depends on natural and human causes. As the key climate change indicators such as increasing temperature and intensity of rainfall are being verified in Nigeria, the consequent impacts of climate change connected to these symptoms are to be expected in Nigeria. With the increasing incidence of climate change related hazards and disasters, considerable damage to buildings and infrastructure is expected. Lagos being one of the largest/fastest growing cities in the world and the foremost manufacturing port city in West African sub region is chosen for this study. Its importance as the economic hub of Nigeria, its coastal position, the peculiarity of building development makes it an ideal State for the study of the impact of global climate change on Nigerian built environment. This research uses statistical methods to analyze rainfall, temperature and structural failure data of Lagos State and postulates their impacts on constructed facilities in Lagos Cosmopolitan urban area. The results confirm the vulnerability of Lagos environment to climate change and the trend of the impacts of flooding on Lagos built environmen