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Tropical clay soil was compacted at different moisture conditions (dry, wet and optimum) and compactive efforts (Reduced proctor, Standard proctor, West African standard and Modified proctor). Experimental Soil-Water Characteristics (SWC) of the soil was derived using the pressure plate extractor equipment and SWC Curves (SWCC) plotted as gravimetric water content versus logarithm of matric suction. The Air Entry Values (A.E.V) obtained from experimental work ranged from 21 kPa to 59 kPa and compared favourably well with those estimated from predictive models with values of 23 kPa to 52 kPa. Specimens compacted with greater compactive effort (Modified proctor) and at optimum moisture content produced the largest air entry value of 59 kPa and reduced air voids. Changes observed in the shape of the SWCC were consistent with changes in pore size which occurred by varying compaction conditions. The shape of the soil-water characteristics curve was found to depend on the soil structure, compactive water content and compactive effort and not solely on the percentage of fine particles.

The research evaluated the failure susceptibility of biopolymers (Guar Gum, Xanthan Gum, Bentonite) and polyvinyl acetate (PVAc) stabilized soil samples from three failed locations along Oshogbo – Iwo Road’s using the TDRAMS mathematical model formulated by Aderinola et al., (2015). The stabilizers were added to the soils in concentrations of (0.25-2) % Biopolymers, (1-3) % Bentonite and 2% PVAc. The samples were classified according to AASHTO as A-5 (slty-sand) and ML group (inorganic silts, sfine sands with low plasticity) based on USCS classification system. Geotechnical tests carried out on both natural untreated and treated samples showed that the natural soil samples gave OMC values of between (11.7-14.97) %, MDD (1644-1453.6) Kg/m3, and soaked CBR (2-6) %. 1% Guar gum, 1 % Xanthan gum, 3% Bentonite and 2% Poly vinyl Acetate were deduced to be optimal mixes for improved strength. However, Guar gum was observed to be the best stabilizer. With the TDRAMS model, 1% Guar gum reduced the failure susceptibility indices of the road by 11.02 % (i.e. from 127 to 113). However, for maximum benefits to be achieved from the stabilization, other factors like provision of good drainage facilities, adequate road sections etc. must be provided. This will help in improving the strength of the subgrade soils and overall durability of the road.

Precipitation erosivity propels detrimental hydrological happenings with substantial eco-friendly and socio-economic influences. The conception of the precipitation-vegetation interface is very vital for implementing acclimatization and mitigation techniques for terrestrial bionetworks. Numerous investigations have reconnoitered the spatial correlation of precipitation-vegetation context along the season-precipitation quantity gradient. Here, comprehensive scrutiny of spatio-temporal patterns of climatology-vegetation response to seasonal variability incongruities in River Ikpoba, southern Nigeria, using principal component scrutiny (PCS), semivariogram, cross-validation statistics, spatial distribution mapping, and hydrological indicators for multi-source climatic datasets for pre-impact flow (1913–1966) and post-impact flow (1967–2022). PCS outcomes reveal seven PCs whose eigenvalues were greater than one were hauled out of the twenty-five variables. The River Ikpoba water quality variables displayed a moderately strong rate of spatial reliance, which made it possible to create the spatial distribution map for the carefully chosen water quality variables. Results from further scrutiny of the river Ikpoba flow duration curve show the highest flow rate value between 900–1000cms for the month of October. The post-impact flow's highest value was 65cms in 2008, whereas the pre-impact flow was 64cms. Likewise, 90 days’ minimum highest flow rate was 250cms, 30 days was 1180cms, 7 days was 105cms, and 1 day was 105cms. Whereas the maximum for 1 day was 7200cms, 3 days’ value was 6400cms and 7 days' was 4500cms. This indicates that as the day progressed, the flow rate was increasing for a consecutive 30 days at a low flow rate, but at 90 days it declined. As the day progresses, the values for the maximum value decrease. Doi: 10.28991/HEF-2022-03-01-02 Full Text: PDF

This paper investigates transport system and sustainable improvement in North-central, Nigeria with specific reference to Abuja, Nasarawa and Niger State. Survey research device was utilized with questionnaire as main instruments applied for data collections which were dispensed to four hundred travellers carefully picked randomly making total of 1200 travellers that were studied. From demographic figures for each of the three zones, female travellers more than men, Self-employed travellers has the highest, between 25 and 40 years travelled most, Christian travellers are more than other religions, while travellers with at least degree certificate travelled most and the highest income is below minimum wage. Nevertheless, from the opinion about public transportation system, majority testify that fare is too costly, deficient bus service and inaccessibility or costly parking space, whereas safety and cleanliness is zero percent.