Production and Cost of Cold Patch Road Mats with Bitumen Extracted From Nigerian Tar Sand

This paper reports the production of bituminous road mats with bitumen sourced from the Nigerian Tar sand, recycled waste rubber and paper, and rock mineral aggregates for cold patching of flexible pavement. The bitumen extracted was evaluated for yield, physical and mechanical properties in accordance with ASTM and AASHTO procedures. The bitumen was mixed with rubber chips to produce rubberized bitumen for production of road mats. The unit cost of production per square metre of the road mat was developed and compared with that of the imported Broom Road Product (BRP). The bitumen extracted from the Nigerian tar sand is suitable as straight run bitumen and production of bituminous cold patch road mats at relatively cheaper cost than the BRP. An immediate action plan for exploitation of the untapped resources of bitumen should be instituted by government and private entrepreneurs for production of road mats for cold patching of flexible roads.http://dx.doi.org/10.4314/njt.v34i2.

Design and Economic Analysis of a Flexible Pavement on a Geosynthetic Reinforced Subgrade

This study investigated the effect of geogrid reinforcement on the  mechanical property of an unsuitable road soil with respect to appropriate placement in the pavement structure and implication on the cost of the development of the road. Sample was collected from the stockpile of an unsuitable soil material at a bridge site and subjected to identification, geotechnical strength (CBR) and chemical stabilization tests. CBR strength evaluation test was further performed on the soil sample when reinforced with the use of a geosynthetic, triaxial geogrid (Tx 160). A flexible pavement structure was designed for low, medium and heavy traffic level using three design methods with the improved soil subgrade. The corresponding relative cost advantages were also determined using the pavement thickness reduction factor. The results established the geogrid reinforcement is a better alternative to chemical stabilization of an unsuitable AASHTO A-4 soil. The design results denoted a significant  pavement thickness reduction factor as a result of geogrid reinforcement within 13% - 67% savings in pavement thickness for all the pavement design methods employed. The use of geogrids should, therefore, be encouraged as an economic form of improving subgrade soils for pavement works.Keywords: geogrid, flexible pavement, chemical stabilizatio

MODIFIED TRAFFIC SIGNAL PHASING AT TRAFFIC WARDEN CONTROLLED INTERSECTION TO ACCOMMODATE PEDESTRIAN TRAFFIC IN ILORIN METROPOLIS, NIGERIA

The study addresses the nervous anxiety always noticed in pedestrians as they cross at a 4-arm, Traffic Warden Control intersection in Ilorin metropolis, Nigeria. Two of the approaches (Challenge and Unity) are dualised multilanes while the other two (Obbo and CocaCola) are two-lane non-dualised. The present 4-phase traffic control scheme does not give consideration to pedestrian crossing. The geometric layout and the existing traffic management practice at the intersection were determined and a pedestrian traffic survey was conducted. The critical pedestrian volume of 171 pedestrians/hr was obtained on Challenge approach. Using an average walking speed of 1.2 m/s and a crosswalk width of 3 m a pedestrian crossing time of 787.88 seconds within one hour is obtained as being adequate for the critical approach.  A 5-phase scheme is proposed with the fifth phase being an all-stop exclusive phasing for pedestrian movements. Crosswalk should be introduced to concentrate pedestrian crossing activity at a specific location thereby positioning pedestrians to be more visible to traffic wardens and motorists.  http://dx.doi.org/10.4314/njt.v35i1.

Role of Geomatics in the Management of Disasters and Infrastructural Failures

The article identifies the role of Geomatics in the highly interdisciplinary disaster management to include identification and mapping of hazard prone areas, deformation monitoring of hazard prone areas and massive engineering structures, production of rescue maps and assessment of damages among others. A case study of surveying activities in the proposed flood management of Asa River in Ilorin metropolis, Nigeria was presented. The study identified possible causes of the flood to include silting along the river, blockades of free flow of water resulting from human activities such as dumping of refuse in the river and natural causes such as growth of vegetation along the river channel. The study recommends the development and deployment of Geomatics potentials in the three phases of disaster management namely; pre-disaster phase, disaster phase and post disaster phase.Keywords: Geomatics, Disaster, Mapping, Assessment, Managemen

RESEARCH EFFORTS ON INTELLIGENT TRANSPORTATION SYSTEM IN NIGERIA: DEVELOPMENT OF TRIP PLANNING MODELS

The critical situation of unwelcome frustration experienced by urban trip makers and roadside dwellers alike, calls for a very strong push by all stakeholders in the transportation sector to enhance the service performance of transportation facilities using Intelligent Transportation Systems (ITS). Needed strategies for successful ITS implementation in both developed and developing nations, include but not limited to policy formulation and planning, funding of ITS projects, development and deployment of research products, system performance measurement, optimization of the performance of existing infrastructure, capacity building, etc. which could be much promoted with research efforts. Advanced Public Transportation System (APTS) and Advanced Traveller Information System (ATIS) categories as products of research on ITS were developed with data derived from urban trip makers on captive corridors, both in Ilorin, Kwara State and Minna, Niger State, Nigeria. The fundamental basis and status of the research activities targeted at developing and deploying the ITS in Nigeria are highlighted in the paper. http://dx.doi.org/10.4314/njt.v35i3.

A Markov deterioration model for predicting recurrent maintenance of a network of roads: a case study of Niger state, Nigeria.

The parameters of the Markov chain model for predicting the condition of the road at a design · period for· the flexible pavement failures of wheel track rutting, cracks and pot holes were developed for the Niger State· road network . in Nigeria. Twelve sampled candidate roads were each subjected to standard inventory, traffic count and pavement condition study, whose outcome together with the temperature and rainfall characteristics. were used to generate a computerized data base. A Markov transition probabilistic model · (TPM) was subsequently developed. The prevailing condition of each of the three selected parameters were set out in five severity bands and established intervention levels in respect of proportional distribution of the failures across the three geo . political maintenance zones of the network. The TPM was developed by adopting Costello (2005) respective criteria for Mediterranean and cold region climate and weather. The relevance of the outcome for stochastic analysis and design of budget for recurrent maintenance of a road network was highlighted in the paper.KeYWords: large· and complex system,· condition deterioration, Markov. chain, transition probability matrix

Similarities between disaster supply chains and commercial supply chains: a SCM process view

© 2017, Springer Science+Business Media, LLC. The purpose of this paper is to demonstrate conceptual and theoretical similarities between disaster relief chains (DRCs) and commercial supply chains using the customer relationship management process model (CRM) of the seminal global supply chain forum framework (GSCF) as a lens of analysis (Croxton et al. in Int J Logist Manag 12(2):13–36, 2001). A range of empirical data from a case study of the 2006 relief and recovery response to the Cyclone Larry disaster is analysed using the CRM process model of the GSCF framework as a lens of analysis. We find that there are unexpected conceptual and theoretical similarities between DRCs in the Cyclone Larry disaster response and commercial supply chains. The study demonstrates that core commercial SCM concepts such as integration and integrative process management can also be found empirically in the domain of disaster response operations and allied management of supply chains for disaster relief and recovery (DROSCM). The study also shows that research in the DROSCM domain can develop in a range of directions unfettered by a paradigm focused on differences between DRCs and commercial supply chains. This is the first study to conceptually, theoretically, and empirically demonstrate similarities between DRCs and commercial supply chains

Maternal and neonatal outcomes after caesarean delivery in the African Surgical Outcomes Study: a 7-day prospective observational cohort study.

BACKGROUND: Maternal and neonatal mortality is high in Africa, but few large, prospective studies have been done to investigate the risk factors associated with these poor maternal and neonatal outcomes. METHODS: A 7-day, international, prospective, observational cohort study was done in patients having caesarean delivery in 183 hospitals across 22 countries in Africa. The inclusion criteria were all consecutive patients (aged ≥18 years) admitted to participating centres having elective and non-elective caesarean delivery during the 7-day study cohort period. To ensure a representative sample, each hospital had to provide data for 90% of the eligible patients during the recruitment week. The primary outcome was in-hospital maternal mortality and complications, which were assessed by local investigators. The study was registered on the South African National Health Research Database, number KZ_2015RP7_22, and on ClinicalTrials.gov, number NCT03044899. FINDINGS: Between February, 2016, and May, 2016, 3792 patients were recruited from hospitals across Africa. 3685 were included in the postoperative complications analysis (107 missing data) and 3684 were included in the maternal mortality analysis (108 missing data). These hospitals had a combined number of specialist surgeons, obstetricians, and anaesthetists totalling 0·7 per 100 000 population (IQR 0·2-2·0). Maternal mortality was 20 (0·5%) of 3684 patients (95% CI 0·3-0·8). Complications occurred in 633 (17·4%) of 3636 mothers (16·2-18·6), which were predominantly severe intraoperative and postoperative bleeding (136 [3·8%] of 3612 mothers). Maternal mortality was independently associated with a preoperative presentation of placenta praevia, placental abruption, ruptured uterus, antepartum haemorrhage (odds ratio 4·47 [95% CI 1·46-13·65]), and perioperative severe obstetric haemorrhage (5·87 [1·99-17·34]) or anaesthesia complications (11·47 (1·20-109·20]). Neonatal mortality was 153 (4·4%) of 3506 infants (95% CI 3·7-5·0). INTERPRETATION: Maternal mortality after caesarean delivery in Africa is 50 times higher than that of high-income countries and is driven by peripartum haemorrhage and anaesthesia complications. Neonatal mortality is double the global average. Early identification and appropriate management of mothers at risk of peripartum haemorrhage might improve maternal and neonatal outcomes in Africa. FUNDING: Medical Research Council of South Africa.Medical Research Council of South Africa