http://196.220.128.81:8080/xmlui/handle/123456789/190 2026-04-26T16:53:42Z 2026-04-26T16:53:42Z OMOYAJOWO, KAYODE http://196.220.128.81:8080/xmlui/handle/123456789/5575 2023-02-07T10:23:05Z 2021-05-01T00:00:00Z

COMPRESSIVE STRENGTH ASSESSMENT OF CONCRETE WITH DIFFERENTNALKALI-ACTIVATED POZZOLLANS AND 15 TO 20% REPLACEMENT OF SAND WITH LATERITE OMOYAJOWO, KAYODE The ever increasing rise in the cost of cement and the threat on the environment during its production have led to the continuous search for alternative binding materials in its place. Researchers have been looking into the possibility of harnessing both artificially and naturally occurring materials to partially or wholly replace cement in the construction industry. Materials such as slag, fly ash, wood ash and corncob ash which have cementitious properties, have been investigated, while works have been intensified on the use of metakaolin, rice husk ash, palm oil fuel ash as cementitious materials in the last decades. This work looked into how best Alkaliactivated pozzolans like metakaolin, rice husk ash and palm oil fuel ash can be blended together to replace cement partially in varying proportion and at the same time, 15% and 20% by mass of sand was also replaced with laterite. Cement, sand and granite were mixed in the ratio of 1:2:4 to serve as control test. It was on this platform that the Alkali-Activated Pozzolans were blended with cement by replacing cement with Alkali-activated pozzolans up to 40% and also sand with laterite up to 20% by mass of cement and sand respectively. The Alkali used are Sodium Hydroxide (NaOH) and Sodium Silicate (NaSiO3) in ratio 1:2.5 while Alkali/Pozzolan were mixed in the ratio of 1:2. Chemical tests were conducted on the selected materials and the results showed that they all have pozzolanic characteristics. The compressive strength tests revealed that cement can be partially replaced in concrete with the blend of Alkali-activated pozzolans (metakaolin, rice husk ash and palm oil fuel ash) for up to 40% by mass of cement with laterite replacing sand for up to 20% by mass of sand with the water/cement ratio of 0.5 and 0.65. For instance, at 7 and 28days, the compressive strength test on concrete mixed in ratio 1:2:4 of cement, sand and granite at w/c ratio of 0.5 gave 10.30N/mm² and 17.52N/mm² respectively. However, on replacing cement with Alkali-activated Pozzolans of 5% Metakaolin (MK), 5% Rice Husk Ash (RHA) and 15% Palm Oil Fuel Ash (POFA), termed MR5, P15, and replacing sand with 15% laterite at 0.5 w/c ratio, 9.15N/mm² and 15.5%N/mm² compressive strength were obtained at 7 and 28days respectively. At 60days, more strength was gained by the mix with Alkali-activated Pozzolans than the mix without Alkali-activated Pozzolans (control) in that the compressive strength of the MR5, P15 rose to 17.10N/mm2 whereas the compressive strength of the control just increased slightly

2021-05-01T00:00:00Z OLOWOSELU, AYODEJI STANLEY http://196.220.128.81:8080/xmlui/handle/123456789/5574 2023-02-07T10:09:05Z 2022-11-01T00:00:00Z

MAPPING GROUNDWATER VULNERABILITY TO CONTAMINATION STRESS USING A MODIFIED DRASTIC MODEL IN URBAN PERI-URBAN ,AKURE. OLOWOSELU, AYODEJI STANLEY Over the years, groundwater vulnerability assessment has proven to be reliable for delineating contaminated or potentially contamination-prone areas. As such, qualitative groundwater vulnerability mapping is widely adopted by researchers as a simple and cheap decision-making tool for protecting groundwater resources from contamination. Therefore, this study assessed groundwater vulnerability to contamination in a highly urbanised basement-complex environment in Akure, Southwestern Nigeria. The vulnerability mapping was performed in a geographic information system (GIS) environment using the original DRASTIC model and a modified form of the DRASTIC model by incorporating two exogenous factors: ‘anthropogenic impact’ (A) and ‘lineament density’ (L); due to their potentially significant impact on the overall vulnerability of groundwater in hard-rock terrains. In addition, the analytical hierarchy process (AHP) was adopted to optimise DRASTIC parameter weights and rates. The result of the original DRASTIC model classified the study area into three vulnerability classes: moderate low (31%), moderate (43%) and high (26%). However, the DRASTIC-AHP and modified DRASTIC-AHP (DRASTICAL-AHP) classified the study area into two vulnerability zones of moderate low (32%) and moderate (68%), moderate (55%) and high (45%), respectively. The integrated vulnerability maps showed that the high-risk zone is concentrated on the southwestern and northeastern part of the study area with shallow buried depth to groundwater, high lineament density and high recharge rates. The validation results obtained from Pearson’s correlation and vulnerability-EC map revealed that the modified DRASTIC-AHP (DRASTICAL-AHP) map presents a more reasonable classification than the conventional DRASTIC model. Overall, a modified GI -based DRASTAL model was proposed that could be adapted to other areas with similar geological/hydrogeological characteristics as that of the study area. Hence, findings from this study can help make informed decisions about groundwater resource management in basement complex terrains.

2022-11-01T00:00:00Z ADERINOLA, OLUMUYIWA SAMSON http://196.220.128.81:8080/xmlui/handle/123456789/5521 2022-12-13T09:54:07Z 1999-02-01T00:00:00Z

DEVELOPMENT OF A ,RATIONAL PROCEDURE FOR PAVEMENT DESIGN ADERINOLA, OLUMUYIWA SAMSON This study seeks to obtain an optimal pavement layout by combining theoretical and experimental field approaches to pavement design thereby side-tracking full-scale tests for each new road. To do this, a comprehensive data on traffic census, fundamental properties of road materials such as asphalt, laterites and stabilized laterites were collected from relevant Ministries, Journals, textbooks, laboratory test reports and engineering companies. A computer (FORTRAN) proqramrne was written using BISAR programme equation in conjunction with Srnith-Vvitczak (1981) equation'. The results were used to obtain a mechanistic pavement design with inputs from American Association of State Highway and Transportation Officials (AASHTO) design guide. The: approach produced an optimal pavement layout of 625mm (total thickness) that can exceed its design life with overloaded traffic. It also compares favourably with former procedures for tropical countries. Further research into this "theory-practical" approach is recommended. M.ENG THESIS

1999-02-01T00:00:00Z OYE, OMOLARA PRECIOUS http://196.220.128.81:8080/xmlui/handle/123456789/5508 2022-12-07T12:45:05Z 2021-12-01T00:00:00Z

UTILIZATION OF CUPOLA FURNACE SLAG AND CERAMIC WASTE IN THE PRODUCTION OF CONCRETE OYE, OMOLARA PRECIOUS This research is on the use of cupola furnace slag and ceramic waste (broken tiles) for concrete production. Tests were carried out on cement, aggregates, cupola furnace slag and ceramic waste (broken tiles) prior to use. Batching by weight was used to produce fresh concrete at a prescribed mix ratio of 1:2:4 and a water cement ratio of 0.55. A total number of 144 concrete cubes were produced, by partially replacing cement and fine aggregate with cupola furnace slag and ceramic waste (broken tiles) powder respectively at various percentage replacement. Tests performed to determine the properties of fresh concrete were slump, compaction factor, setting time and concrete density, while compressive strength test was carried out on hardened concrete after 7, 14, 28, and 56 days curing in water. The average compressive strength of Ordinary Portland Cement (OPC) concrete gives 13.4 N/mm2, 17.1 N/mm2, 23.1N/mm2 and 24.0 N/mm2 after 7 days, 14 days, 28 days, and 56 days of curing respectively. The optimal compressive strength was achieved at mix when 10% cupola slag and 40% ceramic waste (broken tiles) was used to partially replace fine aggregate with 100% cement. This gave 20.1 N/mm2, 24.2 N/mm2, 25.9 N/mm2, and 26.8 N/mm2 after 7 days, 14 days, 28 days, and 56 days of curing respectively. The results at this level is the highest, even for the conventional concrete. In order to determine the optimal mix, analysis of variance was used to analyze the compressive strength results at 56 days of curing. The result obtained shows that, cupola furnace slag and ceramic waste (broken tiles) could be an alternative source of fine aggregate.

2021-12-01T00:00:00Z