Impact of Different Fine Aggregates on the Compressive Strength of Hollow Sandcrete Blocks

Sandcrete blocks are walling materials that are made of fine aggregates and cement. Though, sandcrete blocks are being used as building materials in many parts of Nigeria, it has been discovered that many of the blocks produced do not conform to the minimum compressive strength requirement for such blocks. This study, therefore, examined the effect of using four (4) different fine aggregates (quarry dust, river sand, shocking sand and plastering sand) with binder to aggregate mix ratios of 1:6 and 1:4 on the compressive strength of sandcrete blocks. Specific gravity and particle size distribution analyses were conducted on the fine aggregates to determine their properties while water absorption capacity and compressive strength tests were carried out on the hollow sandcrete blocks. Five samples from each aggregate of size 450 mm x 225 mm x 225 mm were moulded and subjected to compressive strength tests. The water absorption capacity results revealed that shocking sand has the highest capacity to absorb water with a value of 8.69 %. River sand, with a value of 6.67 % has the lowest water absorption capacity. The 28th day compressive strength test results of 1.31 N/mm2, 1.10 N/mm2, 0.78 N/mm2 and 0.50 N/mm2 for the sandcrete blocks produced from quarry dust, river sand, shocking sand and plastering sand respectively, with mix ratio 1:6, did not meet the minimum requirement of 2.5 N/mm2 specified by NIS 87:2007 for non-load bearing walls. However, with mix ratio of 1:4, the compressive strength of 2.52 N/mm2 and 2.50 N/mm2 for sandcrete blocks made with quarry dust and river sand respectively met this minimum requirement. It was concluded that only quarry dust and sharp sand at mix ratio 1:4 are suitable in the production of sandcrete blocks

Comparative study of Ikirun and Osogbo Slag on concrete grade 20

This study examined the use of Prism Steel Slag (PSS) and Machine Iron Slag (MIS) as partial replacement of coarse aggregate in concrete. Coarse aggregates were partially replaced with PSS and MIS at 0%, 10%, 20%, 30%, 40% and 50% respectively. A total of 132 concrete cubes of sizes 150 mm x 150 mm x 150 mm were cast and cured in water for 7, 14, 21 and 28 days respectively. Mix ratio of 1:2:4 was adopted with w/c ratio of 0.45 and batching was done by weight. The slump result indicated that the fresh concrete becomes stiff as the percentages of PSS and MIS increases. However, the compressive strengths of concrete cubes increased as the curing ages increases. 50% PSS and 40% MIS can successfully be used as partial replacement of coarse aggregate in the production of concrete grade 20.Keywords: Concrete, Coarse Aggregate, Strength, Machine Iron Slag, Prism Steel Sla

Evaluation of building security costs determinant within the built environment in Minna, Niger state, Nigeria

Building equipped with protective measures is exceedingly restricted but it brings about a moderately high increment in expenses of building security and the general cost of the home. This study aims at assessing the built environment experts’ perception of factors affecting the cost of maintaining security in houses as a part of sustainable building security cost. The study employed mixed methods sequential exploratory design to source data primarily from the respondents. Purposive and convenience sampling were used for data collection while descriptive statistics and inferential were employed for data analyses. The results revealed insignificant difference in respondents’ perceptions on building security costs. The top ranked respondents’ perceptions were from Builders, Quantity Surveyors and Architects with total mean scores of 267.08, 234.66 and 234.63. No significant variations were shown among the mean scores of the items ranked. This is an indication that all items are important therefore having effect on building security costs. The study concluded that external wall openings access prevention, size of building, perimeter fence and protection are some of the key criteria for measuring building security costs. The study sensitizes the built environment experts, criminologists and policy makers about the implication of the established factors on building security costs. Keyword: Built-Environment, Building security, Cost determinant, Experts’ perception