Volume 33(1) 2021

Table of Contents

Front Page

Review Papers

No. Article Page  
1. Penggunaan Teknologi Kejuruteraan dalam Pendidikan STEM Bersepadu

Use of Engineering Technology in Integrated STEM Education

Yusriza Mohamd Yusof, Afida Ayob* & Mohamad Hanif Md Saad
Abstrak Bahasa Malaysia

Teknologi merupakan salah satu elemen dalam STEM iaitu STEM membawa maksud Sains, Teknologi, Kejuruteraan dan Matematik. Pendidikan STEM bersepadu pula adalah salah satu kaedah agar pembelajaran menjadi lebih bermakna kepada murid dengan mengaplikasikan pelbagai kaedah pembelajaran. Salah satu pendekatan yang digunakan ialah menggunakan kaedah pembelajaran berasaskan projek (PjBL) yang dapat menjadikan pembelajaran lebih bermakna. Penggunaan teknologi dalam pendekatan STEM bersepadu melalui kaedah pembelajaran berasaskan projek (PjBL) di peringkat sekolah telah diaplikasi di kebanyakan negara maju seperti Amerika Syarikat, Jepun dan Australia. Artikel ini akan mebincangkan tentang penggunaan teknologi dalam pendidikan STEM bersepadu terutama dalam mata pelajaran kejuruteraan iaitu topik Elektronik bagi murid menengah rendah di Malaysia dan beberapa negara lain iaitu Australia, Jepun dan Amerika Syarikat. Perbandingan ciri penggunaan teknologi dalam pendidikan STEM merujuk kepada topik Elektronik dalam Dokumen Standard Kurikulum dan Pentaksiran (DSKP) mata pelajaran Reka Bentuk Teknologi (RBT) Tingkatan 2 dan 3, pendidikan STEM peringkat global serta yang sedang digunapakai di sekolah-sekolah menengah di Malaysia. Cadangan teknologi berasaskan kejuruteraan yang sesuai digunakan serta modul pembelajaran yang boleh direkabentuk sesuai dengan kehendak DSKP mata pelajaran RBT dan Pelan Pembangunan Pendidikan Malaysia 2013 – 2025 (PPPM 2013-2025) turut dikemukakan supaya modul pembelajaran yang dibangunkan hasil daripada kajian yang dijalankan dapat digunapakai oleh guru dan murid.

Keywords: STEM; teknologi; reka bentuk teknologi

Abstract English

Technology is one of the elements in STEM that STEM stands for Science, Technology, Engineering and Mathematics. Integrated STEM education is one way to make learning more meaningful to students by applying a variety of learning methods. One of the approaches used is the project-based learning method (PjBL). The use of technology in an integrated STEM approach through school-based learning (PjBL) methods has been applied in many developed countries such as the United States, Japan and Australia. This article will discuss the use of technology in integrated STEM education, especially in engineering such as electronics for elementary students in Malaysia and other countries. Comparison of the features of technology use in STEM education refer to the documents of the Curriculum and Assesment Standards Document (DSKP) of Technology Design (RBT), global and STEM education currently in use in Malaysian secondary schools. Proposed engineering-based technology proposals and learning modules that can be designed in accordance with the requirements of the DSKP of Technology Design (RBT) subjects and the Malaysian Education Development Plan 2013 – 2025 (PPPM 2013-2025) have also been submitted for the module learning developed as a result of the research conducted can be used by teachers and students.

Keywords : STEM; technology; design and technology

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-01
2. Effect of Springback on A6061 Sheet Metal Bending: A Review

Zeki Murat Cinar, Mohammed Bsher A. Asmael* & Qasim Zeeshan

Springback is defined as undesirable shape change that occurs after forming process upon unloading due to the occurrence of elastic recovery of the part. Aluminum alloy with high content of magnesium such as A6061 is preferred for high formability limit to be used in automotive industry. However, generally springback turns out to be a drawback. Many researchers have examined the springback of A6061 by considering parameters such as bent angle, die shoulder radius, blank holder force, sheet thickness, punch thickness, modulus young, yield strength, Poisson’s ratio, annealing temperature, applied load and bending operations such as V bending, deep drawing, tube bending, 3 point bending, U bending, and wipe bending. In this research, a comprehensive review is carried out to investigate process parameters and bending operations having critical impact on springback of A6061 and publications in the literature based on springback effect for A6061 studied in order to observe the number of publications by authors and the number of publications by affiliation. It is observed that sheet thickness and bent angle parameters have substantial effect on the springback. V bending and deep drawing are the commonly used bending processes. In addition, a critical contribution is presented by considering process parameters and analysis methods in order to provide a guidance for researchers for further research studies.

Keywords: A6061 alloy; Springback; Design of Experiments (DOE); Failure Analysis; Mechanical Properties.

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-02
3. Coconut Shell Ash as Cementitious Material in Concrete: A Review

Naraindas Bheel*, Sajjad Ali Mangi & Shanker Lal Meghwar

In recent years, there has been great concern about introducing new supplementary cementitious materials (SCM) in place of ordinary Portland cement (OPC) in concrete. The aim of this study is to check the behavior of coconut shell ash (CSA) with various proportions in concrete. Coconut shell is available in abundant quantity in local agricultural fields and considered as waste product. On the other hand, cement production emits a lot of toxic gases in the atmosphere which causes environmental pollution and greenhouse gases. Thus, CSA might be utilized as a cementitious material in concrete for sustainable development. This review article provides a detailed overview of the fresh and mechanical properties of various research studies. It is found that by incorporating the 10% of CSA into concrete results in the improvement of mechanical properties of concrete such as compressive, split tensile strength and flexural strength of concrete after every curing day respectively. Moreover, the modulus of elasticity enhanced while using 10% of CSA in concrete and the workability of fresh concrete was declined as the percentage of CSA increases. In addition to that, the use of CSA in concrete can reduce the total carbon foot print while reducing the overall cost of concrete manufacturing.

Keywords: Coconut shell ash; cement replacement material; mechanical properties; reduce the environmental issue

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-03
4. The CPEC Supply Web Framework in Context of Modern Manufacturing

Salman Abubakar Bugvi*, Khurram Hameed, Amjad Hussain & Salim Abid Tabassum

There is a need to understand and integrate the technologies and concepts of the 4th industrial revolution (Industry 4.0), supply chain management, modern manufacturing and the opportunities provided by the logistic and development programs of Belt Road Initiative (BRI) and China Pakistan Economic Corridor (CPEC). The knowledge of multiple fields such as industry 4.0, supply chain management, logistic supply chain management and CPEC project plans have been synthesized. An attempt has been made to model a future state created through CPEC facilities and initiatives. A model framework is presented based on the core infrastructure of CPEC projects, which will push Pakistan towards industrialization through utilizing modern manufacturing techniques and establishment of supply web. The CPEC supply web model proposes to create high quality, mass customized products from raw material and parts to be supplied from local and nearby regions through efficient logistic pathway of CPEC and BRI. A supply chain operational reference (SCOR) model has also been developed for an insight into the scenario. It is important for investors, trade associations, businessmen and policy makers to understand the population, market, and economic dynamics along with modern manufacturing trends to create smart factories and supply chains in context of CPEC. The lessons learned from the planning, development and application of the solutions presented by CPEC can be utilized by other regions and countries depending on their relevant unique geostrategic and economic perspectives.

Keywords: CPEC; Industry 4.0; smart factory; supply chain; logistics management

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-04

Original Research Papers

5. Comparison of Green Design Strategies in Five Traditional Malay Houses

Nor Afifah Husen & Mohd Farid Mohamed

The traditional Malay house architecture is undoubtedly one of the ideal green ideal design concepts that can be applied in Malaysian housing development for sustainability. Not only does it have unique features that symbolize national identity, but it is also an important example with various design strategies for habitable space based on local climate and sociocultural aspects. Nowadays, Malaysia’s construction sector has changed due to modernization and being replaced and disintegrated by modern influences. Thus, it erodes the values of the existing green design approaches commonly found in the design of traditional Malay house architecture, that respond well to the local sociocultural and climate conditions. The objective of this study is to identify the green approaches in traditional Malay houses in Malaysia. This study used a qualitative approach, which is a combination of literature studies and site observations. For the site observations approach, it limited to traditional Malay houses from five out of eleven states in Peninsular Malaysia. The investigated traditional Malay houses are from Negeri Sembilan, Pahang, Perak, Terengganu, and Kelantan. The findings of the study show that the architecture of these traditional Malay houses have many green design strategies which prove the sustainability aspect exist in all investigated traditional Malay houses. Thus, this study lists 22 of typically found green design strategies in traditional Malay houses and it can be used as reference or guideline for designing homes in Malaysia.

Keywords: Green design; Malay traditional houses; sustainable

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-05
6. CBlood Cell Tracing in a Microchannel by Using Dielectrophoresis Force

Nur Tantiyani Ali Othman* & Farah Syafiqah Abul Kalam

The conventional techniques of platelet separation are by using a centrifugation and acoustic. However, by using these techniques, the platelets become active due to the relatively high-speed centrifugal force and large amount of a sample usage. Therefore, to overcome this problem, an electric separation technique is preferred as it relies more on the dielectric properties of particles, that allow for highly selective and sensitive analysis. One of them is dielectrophoresis (DEP), which is the force resulting from an interaction between bipolar particles in a non-uniform electric field that can be used to separate neutral particles. The DEP force allows the separation of platelets from red blood cells due to dielectric properties of the particles and medium as it requires small quantities of samples, lower reagents usage, and low-cost equipment. In this study, H-type microchannel with two inlets and outlets was developed by using COMSOL© software to observe the cell distribution at blood concentrations; CA=0.01, 0.015, 0.02, 0.025 and 0.03 mol/m3, with feed velocities at the inlet B; vB=600, 700, 800, 900 and 1000 μm/s and at voltages charged; V=-30V to 30V that applied at the five electrodes. The simulation results show the optimization of blood cell concentration and velocity were achieved at the outlets at CA=0.01 mol/m3 and vB=800 μm/s, respectively. Moreover, the optimum voltage for platelet cell separation was at V=10V as it shows the highest DEP force; FDEP=-3.19×1013 N/m as compared to the other tested voltages.

Keywords: Blood cell; dielectrophoresis; particle tracing; microchannel; COMSOL©

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-06
7. Three-Axes Rotation Algorithm for the Relaxed 3L-CVRP

Irma-Delia Rojas-Cuevas*, Santiago-Omar Caballero-Morales, Diana Sánchez-Partida & José-Luis Martínez-Flores

The purpose of this work is to present a developed three-axes rotation algorithm to improve the solving methodology for the relaxed 3L-CVRP (Three-Dimensional Capacitated Vehicle Routing Problem). Although there are reported works on solving approaches for the relaxed 3L-CVRP that consider product rotation to optimize load capacity, rotation on the three axes has not been thoroughly studied. In this aspect, the present work explicitly explores the three-axes rotation and its impact on load capacity optimization. In order to improve the relaxed 3L-CVRP problem, a two-phase solution was developed. The first phase consists of finding the solution for the CVRP problem, using a demand previously obtained with a heuristic developed to convert the 3L-CVRP demand into CVRP demand. The second phase is to obtain the loading of the vehicle using a heuristic developed to load the items using rules to obtain the rotation of the items. The proposed approach was able to improve the load assignment in 48.1% of well-known 3L-CVRP instances when compared to similar approaches on the relaxed 3L-CVRP. The outcomes of this research can be applied to transportation problems where package rotation on the z-axis is an option, and there are not fragile items to load in the vehicles.

Keywords: 3L-CVRP; constraint relaxation; three-axes rotation; load capacity optimization

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-07
8. Enhancing Green Product Competitiveness through Proactive Capabilities of Manufacturing Firms

Norhuda Salim, Mohd Nizam Ab Rahman* & Dzuraidah Abd. Wahab

The development of innovative green products that can compete in unpredictable markets is a challenge for manufacturing firms. Hence, firms need to reconfigure their strategies by considering and strengthening the appropriate set of internal capabilities to achieve effective green product development. Therefore the initiatives implemented by firms in relation to their green practices and green innovation are attracting increasing scholarly attention. However, thus far only a few studies have explicitly explored the relationship between the proactive capabilities of manufacturing firms in the context of green product innovation. Thus, this study investigates the environmental proactivity (EP) and strategic flexibility (SF) of firms, and how these proactive capabilities affect green product innovation (GPI). In addition, it explores the role of GPI in enhancing product competitive advantage (PCA). The data for this study was obtained from 157 respondents representing manufacturing firms in Malaysia. Structural equation modelling was used for the statistical analysis. The results showed that SF partially mediates the relationship between EP and GPI, which indicates that SF facilitates GPI implementation. The results also revealed that GPI acts as a full mediator between SF and PCA, proving that GPI is the crucial factor that can translate SF into competitive advantage. Thus, based on the dynamic capabilities perspective, this study offers insights into the importance of flexibility and innovation in the context of green manufacturing as a means to enhance green product features and remain competitive in the market.

Keywords: Environmental proactivity; Strategic flexibility; Green product innovation; Product competitive advantage

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-08
9. Microcontroller based Autistic Child Monitoring System in Bangladesh

Nahida Nigar

Children with developmental disorders and their families face major challenges in managing the risk to a disabled child, who may be prone to becoming lost away from their own home. Health and Social care system in Bangladesh has not yet developed the capacity and infrastructure to provide safety services to children with ASD (Autistic Spectrum Disorder). There are no nationwide statistics of Autistic Children in Bangladesh. As per the global prevalence rate, 1 percent of the world population has autism. One in 160 children has an ASD. Since there are 55 million children in Bangladesh below age 14, there may be 550,000 autistic children. As the physically challenged child cannot take care of themselves and no one is there who can keep observation 24-hour like whether the child is getting panic, whether the child is on safety zone or changed his position elsewhere, whether he falls, etc. We have to keep them safe as the number of accidents with children is increasing. Our research study proposed the development of a wearable smart device, which can be a belt, wristwatch or locket. The developed device include a Microcontroller (PIC-16F876A), a global positioning system (GPS), global system for mobile (GSM), and switching unit and the monitoring unit includes sensors and mobile device in parent’s hand with which parents can find the current location of the child by using Google Map. This device ensures 24-hour monitoring and works as an interface between child and parents for emergency response.

Keywords: Microcontroller: global positioning system; GSM; sensor

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-09
10. Hydrophobic Polyvinylidene Fluoride Membrane Modified with Silica Nanoparticles and Silane for Succinic Acid Purification Using Osmotic Distillation Process

Jun Ying Tan, Wei Lun Ang* & Abdul Wahab Mohammad

Recently, osmotic distillation (OD) has emerged as an alternative process for the concentration and purification of heat sensitive components. However, OD performance was severely affected by membrane fouling and wetting, which could be minimized through membrane surface roughness creation and surface energy modification. This study incorporated silica nanoparticles and coated tridecafluro-1,1,2,2-tetrahydrooctyl-1-triethoxysilane at various concentration onto polyvinylidene fluoride (PVDF) membrane to improve its hydrophobicity, limiting the contact between foulants in feed solution and membrane surfaces. Generally, the addition of silica reduced the water contact angle (WCA) of the membrane, but the inclusion of silane had increased it. These membranes were then tested through OD with 1 wt% succinic acid feed solution and 50 wt% calcium chloride stripping solution. PVDF membranes that have been modified with 1 wt% silica nanoparticles and coated with 1:50 volume ratio silane solution achieved a transmembrane flux of 0.6019 kg/m2⋅h, the highest flux among silanated membrane. This was due to the larger pore size retained after silanization. A rejection rate of 95.66% and above were achieved by the membranes fabricated in this study. Overall, PVDF membrane modified with silica and silane had been successfully utilized in OD process and shown potential as a concentration and purification process.

Keywords: Osmotic distillation; silica nanoparticles; silane; hydrophobic

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-10
11. Epoxy/Copper Oxide Composite Coating for Marine Application

Kautsar Binti Tabri, Nor Yuliana Yuhana* , Jafreena Adira Jaafar, Ahmad Faiz Al Shafiei & Mohammad Aslamilie Mohd Suhil

This research investigated the usage of cuprous oxide powder as filler for epoxy in marine coating industries. The basic formulation consist of cuprous oxide powder, epoxy pre-polymer, and the curing agent. The main manipulation variable in this research is the quantity of cuprous oxide added into the epoxy resin, which varies from 2, 5, 7, 9, and 11 per hundred gram of epoxy resin (phr). Polyether (amine) was used as the curing agent at equivalent molar ratio. Mechanical stirring was used to achieve dispersion. The samples were cured at room temperature for one week before characterization. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), drop shape, water and brine absorption, hardness, and abrasion analysis were used. Drop shape analysis exhibited the hydrophobicity of the surfaces. According to water and brine absorption test that was carried out, it is found that the unmodified epoxy sample has the lowest absorption of water and brine. The composite coating, which underwent abrasion test, exhibited increasing hydrophobicity of the surface directed on the electrical wave generator in 5 days.

Keywords: Cuprous oxide, Epoxy resin, Hydrophobicity, Curing

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-11
12. Palm Oil Mills Odour Emission Survey based on Different POME Treatment System

Andrew Yap Kian Chung*, Nastaein Qamaruz Zaman, Fatah Yah Abd. Manaf, Rohaya Mohamed Halim & Rusnani Abd. Majid

Odorous gaseous such as ammonia and hydrogen sulphide produced by anaerobic bacteria are emitted when palm oil mill effluent (POME) is treated via anaerobic digestion. The Department of Environment (DOE) under the jurisdiction of the Air Division has proposed an odour emission limit of 12,000OUm-3 at source sample for Malaysian palm oil mills recently. The objective of this paper is to investigate the odour concentration at effluent treatment area within palm oil mills which practise different types of common POME treatment systems such as Open Ponds Treatment, Covered Lagoon and Digester Tank. The odour source grabbed samples from the respective treatment plants were assessed according to MS 1963:2007 Air Quality – determination of odour concentration by dynamic olfactometry. In addition in-situ odour concentration surrounding the respective project sites have been measured based on enhanced procedures adapted from VDI3940 Grid Method. The survey results showed that odour emitted from Open Ponds Treatment was having highest concentration while Digester Tank was having the lowest concentration due to quarantine factor. None of the observations comply the DOE proposal. Thus, alternative approaches need to be counter proposed in the legislation drafting so that the millers compliance could be ensured while avoid the public sensory annoyance complaints.

Keywords: Odour; palm oil mill; anaerobic pond; POME

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-12
13. Shrinkage Parameters of Modified Compacted Clayey Soil for Sustainable Earthworks

Kennedy C. Onyelowe*, Michael E. Onyia, Duc Bui Van, Ali A. Firoozi, Okorie A. Uche, Seema Kumari, Ismail Oyagbola, Talal Amhadi & Lam Dao-Phuc

The shrinkage limit is one of the Atterberg limits and is a fundamental geotechnical parameter used to assess the settlement and other volume change parameters of engineering soils containing clays. This paper describes shrinkage limits and index tests results on expansive soil treated with rice husk ash (RHA) and 5%, 10% and 15% quicklime activated rice husk ash (QARHA) obtained using laboratory testing procedure. The representative soil was subjected to classification tests and it was found to be high expansive soil, an A-7-6 soil according to American Association of States Highway and Transportation Officials (AASHTO) and poorly graded according to Universal Soil Classification System (USCS). It was classified as highly plastic soil. The soil was subjected to treatment exercise at the rate of 0% (reference), 2%, 4%, 6%, 8% and 10% addition of RHA, 5%-QARHA, 10%-QARHA and 15%-QARHA by weight of dry soil. The RHA addition improved the shrinkage properties; shrinkage limit at varying rates ranging from 5.7%, to 27.9% for 2%, and 10% RHA addition respectively with reference to the control experiment. And for the shrinkage index, the improvement rate was also substantial i.e. 7.8% to 55.7% at 2% and 10% RHA addition respectively with reference to the control experiment. The effect of rice husk ash activated with 5% quicklime lime (5%-QARHA) showed improvement rate of 6.6% and 34.4% at 2% and 10% 5%-QARHA addition respectively with reference to the control experiment. Also, the effect of rice husk ash activated by 10% and 15% quicklime (10%-QARHA and 15%-QARHA) on the shrinkage properties was presented with the rates of improvement which shows that the higher the rate of activation of rice husk ash with quicklime, the higher the pozzolanic performance Finally, rice husk ash and its composites achieved by quicklime activation process have shown to be alternative cementing materials for use as binders in the modification of expansive soils utilized as subgrade materials.

Keywords: Highly expansive clayey soil; shrinkage limit; swelling potential; shrinkage index; adsorbed moisture; black cotton soil; clay activity; clay content; construction materials.

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-13
14. Absorption of Electromagnetic Radiation on Human Lower Back Region

M A Shakoor, M Moyeenuzzaman, R Azim*, S R Chakraborty, M T Islam & M Samsuzzaman

In this paper a simulation study is conducted on lower back region of human phantom to observe the absorption of electromagnetic (EM) radiation. To investigate the effectiveness, EM radiation with different frequencies (1-100 GHz) is administrated step by step in different tissue thickness (up to 25 mm) of lower back region of human phantom and using EM simulator HFSS, return loss (RL) is recorded at every stage. From the results, it is found that when radiation with frequency 0.899 GHz to 1. 089 GHz (~1 GHz) is applied return loss is varies from 0.413 dB to 1.022 dB in different thicknesses. This indicates that only 1.1 % of the incident power is absorbed maximally. When radiation of 9.899 GHz to 10.099 GHz (~10 GHz) frequency is applied, the return loss value obtained is 6.731 dB to 6.280 dB for different tissue thicknesses. This indicates that only 10.1 % power is absorbed maximally. Finally, when radiation with frequency 99.899 GHz to 100.1 GHz (~ 0.1 THz) is applied, the return loss value is found ranging from 26.902 dB to 26.429 dB in different thicknesses which indicates that almost 99.9% of the incident radiation is absorbed by the human tissue i.e. almost 100% of the incident radiation is absorbed in human lower back region in THz range. From therapeutic point of view, almost the entire incident radiation is attenuated to the lower back region with THz radiation which is clinically very useful in treating chronic low back pain.

Keywords: Back pain; infrared radiation; phantom; return loss; terahertz (THz); tissue

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-14
15. Intelligent Street Lighting Energy-Saving System Based on Climate Conditions and Vehicle’s Movements

Adnan Al-Smadi*, Salam Salah, Areen Al-Momani & Majd Al-Bataineh

The huge amount of electric power and cost associated with street lighting has raised the need to investigate both cost issues and environmental concerns. Cities worldwide are increasingly investing in energy-efficient street lighting systems. Modern street lighting technology can lower energy consumption as well as operation and maintenance costs significantly. In addition, bright street lighting can reduce accidents and crime rate in the area. Street lighting is an essential public service that provides a significant factor contributing to the quality of life and productivity of people workforces. This paper proposes an intelligent and energy-efficient traffic sensing system based on the widely distributed street lights. It is intended to observe vehicle’s movement on the road and turn ON a block of street lights ahead of vehicle whenever needed. As the vehicle passes by, the system turns OFF the trailing lights. The brightness (intensity of light) of the street light is adjusted based on the surrounding using LDR sensor. Hence, the street lights will be switched ON in the evening around sunset when a vehicle passes by, and switched OFF in the morning after sunrise when there is sufficient light on the streets. In addition, the proposed system will control the intensity level of the street light using the LDR sensor. The Proteus Software Simulation of the proposed system was performed and tested. Then a hardware prototype was designed and implemented to evaluate the performance of the proposed system. This technology can save significant costs and energy.

Keywords: Light Dependent Resistor (LDR); light emitting diode; street light; PIC microcontroller; IR sensor

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-15
16. Effect of Exploration Depth on Microstructural Behavior of Subsurface Soft Clayey Soil for Foundation Construction Purposes

Kennedy Onyelowe*, Michael E. Onyia, Eze Onukwugha, Richard Udeala, Nura A. Mohammed, & Isa Yakubu

The geomorphological, microstructural pattern and mineralogical configuration of subsurface soils explored from 1-meter, 3-meter and 7-meter depths have been studied for the purpose of foundation materials suitability. Soils samples arehauled from borrow sites to where they are utilized as foundation materials. In very most cases, this exploration is doneat varying depths and soil being an erratic geomaterial change in its important engineering characteristics with depth.This laboratory examination was necessary to establish the microstructural behaviour and pattern of soils when they areexplored from different depths. The samples collected from different depths showed to be A-3 soils according to AASHTOclassification method and poorly graded according to the USCS. Also varying depth of the soil sample was characterizedby a proportional increase in moisture content; this as well applies to the `liquid limit, plastic limit and plasticity indexvalues respectively with an exception in the shrinkage limit, which reduces with increase in depth of soil sample. This can beattributed to the erratic behavior of soil, which makes it change behavior from location to location and from depth to depth,clayey contents changes with depth likewise its desiccation properties. The geomorphology and microstructure of the soilsshow weaker configuration with increased depth of exploration to 7 meters. This shows that for any foundation purposes,soils at both 3 meter and 7-meter depths require treatment to be suitable for construction purposes. Geo-constructions likecompacted earth liner systems, mechanically stabilized earths or backfills, pavement subgrade systems can be constructedwith the studied soils but care must be taken to modify the soils to meet the basic design considerations.

Keywords: Microstructural behavior; subsurface exploration; soft clay soil; foundation construction; scanning electron microscopy; x-ray diffractometer

DOI : dx.doi.org/10.17576/jkukm-2021-33(1)-16