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- ItemOpen AccessPozzolanic activity and characteristic of “Saw Dust Ash (SDA)” as partial replacement of cement for concrete production.(FEIC 2019, 2019-10) AFOLABI, O AConcrete is an important construction material, and presently the production cost is becoming unreasonably higher and increasing exorbitantly, which was believed to be the result of high price of cement. These suggested the search for possible alternatives, which could serve as cementitious binder effectively and comparatively with Portland cement. Research studies on the use of pozzolans, provides the opportunity to investigate saw dust ash (SDA) as a pozzolan for possible use in concrete production as alternate material with cement. The objective of this study includes, the determination of binding strength and capacity of SDA, and properties of concrete produced with SDA as partial replacement of cement in concrete, using the standard test procedures as indicated in “BS 1881 – Testing Concrete”, for laboratory investigations, report and analysis of result. Preliminary study on constituent materials to ascertain their quality and characteristic properties were implemented, which includes, dry and bulk density, sieve analysis, aggregate crushing value test, and chemical properties of SDA and OPC were also determined to ensure the concrete produced are of adequate engineering characteristic properties. The investigation on binding capacity and cementitious activity index was done using the setting times method for cement paste, and the observed results, gave a mean time different between the initial and final setting time as 42mins, 58mins, and 78mins, for the 0%, 7.5%, and 15% replacement level. Concrete specimens were, prepared using a mix-proportion of 1:2:4, and with varying percentage replacement of SDA as, 0, 7.5%, and 15%, by weight of cement, for the workability and strength evaluation. The workability test was implemented to determine, the consistency, homogeneity, and compatibility of fresh concrete, since this phase/stage of concrete, has direct influence on property of hardened concrete, when not adequately prepared. The result of the workability indicated a low slump value, (between 20-40mm), which was specified according to the BS code as 0.85 compacting factor, an indication that describes inadequate fluidity. Specimen concrete cubes (150x150x150mm), were cast for the compression test. They were cured within the laboratory environmental condition with portable water before testing at 3, 7, 14, 21, and 28 days, and the observed results were used for the comparison and analysis of pozzolanic activity and performance of SDA with ordinary Portland cement concrete. Similarly, 9 Nos Concrete beams were prepared and tested for flexural behavior at 28 days. The observed flexural strength value are 6.83N/mm2, 6.44N/mm2, and 5.88N/mm2, for 0, 7.5 & and 15% replacement of SDA, this indicated a reduction with increase in SDA content. Similarly, the failure moment gave a very low magnitude compared to the moment of resistance for concrete beam-section, thereby showing that concrete is weak in tension. In conclusion, the strength activity index were found to be 100%, 83.6%, and 73.4% for the 0, 7.5% and 15% SDA replacement level, which expresses comparable performance and binding capacity of SDA in concrete, and also that the replacement up to 15% SDA is recommended for concrete construction work, where low strength is required.
- ItemOpen AccessContract Law and Management of Engineering Projects(Nigerian Society of Engineers, Lagos Branch, 2013-10) Afolabi, O.Full texts attached
- ItemOpen AccessProcurement Feasibility and Project Needs Evaluation(Nigerian Society of Engineers, Lagos Branch, 2019-09-17) AFOLABI, Olusegun A
- ItemOpen AccessMENTORING: IMBIBING THE SPIRIT OF SELF-REALIZATION AND TECHNICALITY INTO THE POTENTIAL CIVIL ENGINEER(NIGERIAN INSTITUTION OF CIVIL ENGINEERS, YOUNG ENGINEERS FORUM, 2014-10-31) AFOLABI, Olusegun A
- ItemRestrictedSTABILITY OF NIGERIAN HIGHWAY PAVEMENTS DURING CONSTRUCTION AND SERVICE PERIOD(Conference on Innovations in Engineering and Technology, Faculty of Engineering, University of Lagos, 2005-05) AFOLABI, Olusegun A; AFOLABI, Olusegun AIt is an obvious fact that most highway in the country are uncomfortable and intolerable to motorist, this makes travelling on roads a misery to those who could not afford the other transportation options. This situation is as bad that if urgent action is not taken, it could take away the confident and comfort of travelling on roads, which includes the security of being at the wheel by oneself. The big question which puzzles the mind of many is, what could have been the cause of incessant occurrence of failures on our roads, just after construction in Nigeria, thus creating doubts regarding the strength provided for the pavements, since usually a stable pavement should last for the design period (of about 20years) taking the anticipated traffic loads and at minimal maintenance cost. The ground on which pavement are placed consist of soil mass to a reasonable depth within the earth crust and must be made stable at the beginning of a road construction, hence the need for stabilization where the ground is less stable to improve the strength and consequently the pavement structure. When the soil is adequately provided with consideration for climatic variation along the length on the route, there should be little fear of road failure for the intended useage and provided maintenance works are implemented routinely to make up for the service situation and prevailing environmental conditions.