Browsing by Author "Onyelowe, Kennedy"

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    Adsorbed complex and laboratory geotechnics of Quarry Dust (QD) stabilized lateritic soils
    (Environmental Technology & Innovation, 2018) Onyelowe, Kennedy
    The effect of ordinary Portland cement, OPC+Quarry Dust, QD on the adsorbed moisture, diffused double layer (DDL), dielectric constant, density and repulsion potential (RP) of treated lateritic soil was investigated through laboratory tests. The preliminary tests showed that the natural soil was an A-2-7 soil, according to the AASHTO classification system, highly plastic soil and high swelling potentials. The soil was treated with a fixed 5% OPC and varying proportions of QD at 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50% by weight of the dry soil. The stabilization results showed that the compaction properties improved consistently, with the addition of the QD. Also, the addition of the QD reduced the adsorbed moisture and consequently reduced the double diffused layer and the repulsion potential, which constitute the properties investigated within the adsorbed complex in the stabilization operation. These observations brought about the cation exchange reaction between the metallic ions that were attracted to the adsorption complex, resulting to densification, flocculation from the natural state of dispersion of particles and strength gain in the stabilization procedure. Results also showed that the repulsion potential increased in magnitude with the distance between the reactive particles and the clay surface and reduced with increased proportions of QD. The dielectric constant also reduced considerably with adsorbed moisture, which indicated that the dielectric was affected by the moisture and the ions released within the adsorbed complex.
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    Generalized Review on EVD and Constraints Simplex Method of Materials Properties Optimization for Civil Engineering
    (Civil Engineering Journal, 2019) Onyelowe, Kennedy; Alaneme, George; Bui Van, Duc; Nguyen Van, Manh; Ezugwu, Charles; Amhadi, Talal; Sosa, Felix; Orji, Francis; Ugorji, Benjamin
    Extreme vertex design (EVD) has been adapted to be used in the modeling of the behavior of mixture experiments in civil engineering. This method has been in use since the 1970s and has be prevalent in the field of medical science. Various other methods of design of experiments have been used in engineering but neither has EVD being used particularly in civil engineering. This review is presented to serve as a hub or guide for subsequent exercise where concrete production, asphalt production or modification, soils stabilization and concrete improvement or water treatment would be studied with the help EVD. Its ability to fix design points and centroids has been reviewed in this work. EVD operates with various algorithms and depends on the order or condition of problems to be solved. The XVERT algorithm working on Minitab and Design Expert platform was adopted in this review work because of its efficiency in handling quadratic model problems like the four cases reviewed in the present work. From the four special cases, it can be asserted that there is a confidence in the use of EVD to develop the constraints, design the experimental factor space, design the mix proportions, and validate the models resulting from these procedures after experimental specimens are tested to determine the responses.
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    Isolated Effect and Sensitivity of Agricultural and Industrial Waste Ca-Based Stabilizer Materials (CSMs) in Evaluating Swell Shrink Nature of Palygorskite-Rich Clays
    (Advances in Civil Engineering, 2021) Jalal, Fazal E.; Jamhiri, Babak; Naseem, Ahsan; Hussain, Muhammad; Iqbal, Mudassir; Onyelowe, Kennedy
    *is paper evaluates the suitability of sugarcane bagasse ash (SCBA) and waste marble dust (WMD) on the geotechnical properties of Palygorskite-rich expansive clays located in northwest Pakistan. *ese problematic soils exhibit undesirable characteristics which greatly affect the pavements, boundary walls, slab-on-grade members, and other civil engineering infrastructures. A series of geotechnical tests were performed on soil specimens using prescribed percentages of the aforementioned Ca-based stabilizer materials (CSMs). *e investigation includes X-Ray Diffraction (XRD) Analysis, Scanning Electron Microscopy (SEM), X-Ray Fluorescence (XRF) tests, and physicomechanical properties such as moisture-density relationship, Atterberg’s limits, swell pressure, and an ANN-based sensitivity analyses of overall swell pressure development. *e outcomes of these experimental investigations showed that the addition of CSMs into the expansive soils increased to 4% SCBA and 10% WMD, the plasticity index reduced by 30% and 49%, the volumetric swell decreased from approximately 49% to 86% and 63%, and the swelling pressure reduction was from 189 kPa to 120 kPa and 160 kPa (about 15% and 36%), respectively. It is interesting to note that replacement with specified CSM accelerated the strength of soil at extended curing periods and the optimum improvement in the strength behavior of the soil was also recorded. Moreover, with addition of the respective CSMs, the compactability and strength characteristics were ameliorated, while plasticity was significantly lowered. Given the amount of SCBA and WMD produced annually, their utilization for the stabilization of problematic soils, even in relatively low concentrations, could potentially have a substantial impact on the sustainable reuse of these waste materials.
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    Scheffe optimization of swelling, California bearing ratio, compressive strength, and durability potentials of quarry dust stabilized soft clay soil
    (Materials Science for Energy Technologies, 2019) Onyelowe, Kennedy; Alaneme, George; Igboayaka, Clifford; Orji, Francis; Ugwuanyi, Henry; Bui Van, Duc; Nguyen Van, Manh
    Scheffe’s second degree polynomial was used to formulate models for predicting the swelling potential, California bearing ratio, unconfined compressive strength and loss of strength on immersion durability of quarry dust treated soil. These models could predict the swelling potential, California bearing ratio, unconfined compressive strength and loss of strength on immersion durability of treated soil if the mix ratios are known and vice versa. The response predicted by the models are in good agreement with the corresponding experimentally observed results. The result of these tests shows the feasibility of using quarry dust in soil stabilization. The student t-test and the analysis of variance (ANOVA) test were used to check the adequacy of the models, and the models were found to be adequate at 95% confidence level. With the optimized equations, the properties’ design, behaviour, and performance of treated soft clay soil as a pavement subgrade material will be appropriated and monitored. This will be for any possible volume changes, shear failures, strength failures and durability failures when the material used as a hydraulically bound material is in contact with moisture beyond its optimum and subjected to dynamic load beyond its design value.
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    Sorptivity, swelling, shrinkage, compression and durability of quarry dust treated soft soils for moisture bound pavement geotechnics
    (Journal of Materials Research and Technology, 2019) Onyelowea, Kennedy; Onyelowe, Kennedy; Bui Van, Duc; Eberemu, Adrian; Xuan, Man Nguyen; Salahudeen, Bunyamin; Ezugwu, Charles; Nguyen Van, Manh; Orji, Francis; Sosa, Felix; Ta Duc, Thinh; Amhadi, Talal; Ikpa, Chidozie; Ugorji, Benjamin
    The failure of pavement foundation materials as hydraulically bound materials is a worri-some condition facing pavement infrastructures in the developing world. Capillary action leads to swelling and shrinkage, compressive strength and durability problems, which result from sorptivity as a function of hydraulic exposure conditions. Pavement infrastructures a constantly interfaced with rise and fall of ground water level and capillary action hence a study on the sorptivity behaviour of quarry dust (QD) treated soft clay soils was carried out. Preliminary tests were conducted on the test materials for the purpose of charac-terization. The basic test results show that the test soils S1, S2 and S3 were classified asA-2-7, A-2-6 and A-7 soil groups respectively according to AASHTO classification system.Also, they were classified as poorly graded soils but test soils S1 and S2 were observed to be of high clay content (CH) according to USCS. The test soils were equally observed to be of highly plasticity and contains high free swell index properties, hence are expansive.
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    Structural analysis of consolidation settlement behaviour of soil treated with alternative cementing materials for foundation purposes
    (Environmental Technology & Innovation, 2018) Onyelowe, Kennedy; Bui Van, Duc
    The structural analysis of the application of quarry dust (QD), crushed waste ceramics (CWC), palm bunch ash (PBA), crushed waste ceramics base geopolymer cement (CWCbGPC) and palm bunch ash base geopolymer cement (PBAbGPC) in the treatment of soil has been studied. The need to encourage the use of supplementary cementing materials in construction works is of great necessity. This is because of the further damage the emission of CO2 is causing and its contribution to global warming. Laboratory experiments have been adopted to investigate the behaviour of test soil on the addition of admixtures. After the preliminary study, it was shown that the test soil was an A-7 soil according to AASHTO classification system and poorly graded soil of high clay content (GP/CH) according to the USCS. The treatment protocol was used to study the consolidation settlement (CS) of the treated test soil and results showed that the CS reduced steadily at the varied addition of the cementing additives. A more remarkable improvement was recorded with the geopolymer cements (GPC). The results equally showed that the PBAbGPC was observed to be better than the CWCbGPC in the treatment protocol. The exercise not only achieved the ridding the environment of solid wastes but showed that these waste materials could be reclaimed and synthesized into alternative cementing materials to replace ordinary Portland cement and remove its attendant CO2 emission and the global warming effects from the atmosphere.
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    Triaxial and density behaviour of quarry dust based geopolymer cement treated expansive soil with crushed waste glasses for pavement foundation purposes
    (International Journal of Pavement Research and Technology, 2019) Onyelowe, Kennedy; Igboayaka, Clifford; Orji, Francis; Ugwuanyi, Henry; Bui Van, Duc
    The effect of quarry dust based geopolymer cement (QDbGPC) and crushed waste glasses (CWG) on the triaxial and density characteristics of expansive test soil was investigated under laboratory conditions. Quarry dust is a solid waste the management of which poses a big problem to construction and environmental experts. So also is the management of waste glasses. Then again, the use conventional cement poses everyday threat to the environment as its utilization releases huge amount of CO2 to the environment thereby causing increased global warming. However, the utilization of quarry dust in the synthesis of geopolymer cements which is an eco-friendly geomaterial and by extension its use in the soil treatment protocol is the aim of this work. The test soil was observed to be a poorly graded A-2-6 soil according to USCS and AASHTO classification systems respectively. The treatment exercise showed that the shear characteristics of the treated soil improved consistently. The poisson ratio, porosity and submerged density i mproved with increased additives. The stress-strain relationship improved to a very stiff consistency which satisfies the requirements for subgrade and subbase materials in pavement construction. Finally, the utilization of QDbGPC proved to be a good replacement for conventional cement in terms of environmental issues resulting from CO2 emission, resistant to moisture, heat, sulphate attacks, etc on hydraulically bound materials.