Use of expanded polystyrene from disposable food pack as a modifier for bitumen in hot mix asphalt

This study evaluate the use of Disposable Food Pack (DFP) as a modifier for bitumen for an improved Hot Mix Asphalt (HMA). The  bitumen was modified with 2%, 4%, 6%, 8% and 10% DFP obtained from domestic waste. The penetration, ductility and specific gravity of DFP modified bitumen decreased from 68mm to 59.5mm, 110cm to 101cm and 1.025 to 1.012 respectively with increase in DFP, while softening point increased from 49.5 oC to 54.5 oC with increase in DFP. The Marshal Stability results revealed that the DFP modified bitumen increased the stability values of the compacted mixes to a maximum of 9.33kN at 8% DFP content. The flow showed decrease from 3.18mm at 2% DFP to 2.94mm at 10% DFP, whereas the density of the compacted mixes increased to a maximum of 2.293g/cm3 with increased modifier. An Optimum DFP Content of 6.7% by weight of the Optimum Bitumen Content (OBC) isrecommended. Keywords: Bitumen, Disposable Food Pack, Expanded Polystyrene, Hot Mix Asphalt, Modified bitume

Influence of polyethylene from waste pure water sachet on properties of hot mix asphalt

This work evaluate the influence of waste pure water sachet (WPS) as a modifier in Hot Mix Asphalt (HMA). The properties of the constituent materials were determined. Modified HMA samples were prepared at varying concentration of 2, 4, 6, 8 and 10% WPS content by weight of the Optimum Binder Content (OBC). The properties of the modified HMA were determined using Marshall Method of mix design. The properties of the constituent materials showed that they are suitable for HMA production. The modified bitumen showed an increase in softening point (61 – 73.5%), flash point (258 – 2820C), fire point (289 – 3110C) and ductility (92.67 –118.67cm) as the WPS content increases from 2% to 10% while decrease in penetration (62.33 – 56.5mm) as WPS content increases from 2% to 6%. Stability and Bulk density increases from 4.64kN to 8.84kN and 2.21g/cm3 to 2.34g/cm3 respectively while flow, voids in mineral aggregates (VMA) and Air voids decreases from 3.6 to 2.98mm, 23.85 to 20.16% and 19.73 to 13.97% respectively as the WPS content was increased from 2 to 8%. An optimum polyethylene from WPS modifier content of 8% by weight of the OBC is  recommended for use in the HMA. Keywords: Bitumen, Hot Mix Asphalt, Pure Water Sachet, modified bitumen, Marshall Properties, Polyethylene

Development of Rainfall Intensity-Duration-Frequency (IDF) Curve for Abuja, Nigeria

Urban flooding is a major social and economic problem of any nation. The social implication is attributed to loss of lives and property, unwanted displacement and emotional disturbance attached. While that of economic problem is the cost of mitigation of flood and the aftermath solution. Thus, storm water drainage is part of essential modern city infrastructure. The need for proper analysis and design of drainages and other road water facilities cannot be overemphasized. To achieve this, critical analysis of available rainfall data, which is a key input, is required. A 35 years daily rainfall data were obtained from NIMET, from which the analysis was carried out using frequency method. The output generated are presented in graphical forms and model. Ultimately, an IDF curve generated, depicts Abuja rainfall pattern from which a 3-parameter model equation, I = 37Tr0.2 (t + 0.1)−0.9 was formulated. This is site or location specific. The curve and/or the formulated model can be adopted to determine rainfall intensity of Abuja city if the rainfall duration and return period are predictable

Evaluation of reliability index and probability of failure for the improvement of the Nigerian empirical mechanistic flexible pavement analysis and design system (Nempads)

The aim of this work was to evaluate reliability index (RI) with respect to fatigue and rutting within the different seasons peculiar to Nigeria, in order to improve Empirical-Mechanistic flexible pavement design approach, using First Order Reliability Method (FORM). Flexible pavement design involves many uncertainties, variabilities, and approximations regarding the input parameters like material properties, traffic loads. Others include subgrade strength, drainage conditions, construction, compaction procedures and climatic factors such as temperature, rainfall, and snowfall, etc. The combination of the variances associated with input parameters contributes to components and system uncertainty, and this combination of variances can have a significant effect on the predicted performance of the pavement. Reliability in pavement design is introduced to consider these uncertainties. Layers thicknesses, material properties, and Equivalent Standard Axle Load (ESAL) were entered into a multi-layer elastic theory software, ELSYM-5, which in turn were used to calculate strains and stresses for different seasons. The results obtained were entered into Nigerian fitted transfer function distress models to compute allowable ESALS. Miner’s hypothesis theory equation was used to calculate the cumulative damage due to stress and strains generated. A Framework was generated for finding individual reliability index (RI), systemic reliability index (SRI), and probability of failure. The findings showed that Season I (Winter) recorded the highest component reliability index for fatigue (5.63 for Normal Distribution). Season II (Summer) recorded the lowest component reliability index (β) for rutting (5.4 for Normal Distribution). Season III (Spring) recorded the lowest component reliability index for fatigue (1.85 for Normal Distribution