Muhammad A. Dalhat | King Fahd University of Petroleum and Minerals (original) (raw)

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Papers by Muhammad A. Dalhat

Huge amounts of generated non-degradable plastic wastes constitute a major global environmental n... more Huge amounts of generated non-degradable plastic wastes constitute a major global environmental nuisance. The combined annual municipal solid waste (MSW) generation of Saudi Arabian Kingdom (KSA) exceeds 14,000,000 tonnes, with an average per capita of 1.4 kg/day. Plastic wastes constitute up to 10% of these MSW. The local asphalt can only perform satisfactorily without polymer modification in an environment with a maximum pavement temperature below 64°C. But the 7-day maximum pavement temperature ranges between 64°C and 76°C within the Kingdom. Dynamic storage stability, high-temperature performance, non-recoverable creep compliance (J nr), and strain recovering tendency of recycled high-and low-density polyethylene (RHDPE and RLDPE), and recycled polypropylene-(RPP) modified asphalt binders in combination with styrene–butadiene–styrene (SBS) and polybilt (PB) were presented in this study. Improved high-temperature performance was observed. Even though the recycled plastic waste-modified binders lack sufficient strain recovering ability, RLDPE and RHDPE could be utilised along with an elastomeric SBS to achieve a higher recovery and strain resistance, than that which could be achieved if the same amount of SBS alone is used. RPP content above 2% will lead to an unstable modified asphalt binder. The RHDPE content below 4% and the RLDPE content below 6% whether containing either SBS or PB have shown good storage stability trait under mild agitation, in terms of both time degradation and separation.

The amount of solid plastic waste generated from material packages like plastic bottle and simila... more The amount of solid plastic waste generated from material packages like plastic bottle and similar utilities within the kingdom of Saudi Arabia has skyrocketed. This is as a result of the increased level of industrial packaging due to rapid industrialisation and fast urbanisation in the country. The associated cost of managing these solid wastes has also multiplied as the task become difficult and enormous. The effect of polypropylene, high-and low-density polyethylene (PP, HDPE and LDPE)-recycled plastic wastes (RPW) on the viscoelastic performance of the local asphalt binder has been investigated. The recycled plastics were obtained by shredding and grounding the RPW to a desirable size for easier blending with the asphalt binder. All the RPWs result in an improved rutting performance. The RPW-modified asphalts upper PG limit increase by at least one level for each 2% increase in the RPW content, in most cases. An increase of 55, 19 and 9% in resilient modulus (M R) was observed for PP-, HDPE-and LDPE-produced asphalt concrete (AC), respectively. Correlation between the M R of the AC and non-recoverable creep compliance (J nr) of the asphalt binder was established. The obtained viscoelastic properties of the RPW-modified binder was utilised to model a typical pavement section using AASHTO mechanistic empirical pavement design guide (ME-PDG) software. The predicted distresses of the modelled pavement shows significant rutting and fatigue performance improvement for pavement produced with the RPW. Elastomeric type of polymer is required to supplement these RPW to enable them meet the AASHTO TP 70 elastic recovery requirement.

Asphalt-less-Cement-less recycled plastic bounded concretes (RPBCs) were formulated. Some of the ... more Asphalt-less-Cement-less recycled plastic bounded concretes (RPBCs) were formulated. Some of the RPBCs possessed compressive strength similar to asphalt concretes (ACs). And some of the RPBCs are as strong as the Portland cement concretes (PCCs). Crack healing efficiency of the RPBCs is in the order of 92% as opposed to 9% for ACs. The RPBCs showed lower thermal sensitivity and better moisture resistance than the ACs. They exhibits better flexural strength than the ACs and PCCs in some cases. a b s t r a c t Recycled plastic bounded concretes (RPBCs) containing zero asphalt binder and zero Portland cement were formulated. Mechanical properties of the RPBCs was analyzed with reference to Portland Cement Concretes (PCCs) and Asphalt Concretes (ACs). Some of the RPBCs possessed compressive strength similar to the ACs and some even similar to the very strong PCCs. All of the RPBCs exhibited excellent moisture resistance, far better than the ACs in some cases. rPP-bounded concrete exhibits excellent stiffness and a flexural strength, approximately 3 times that of the PCC and 5 times that of the ACs. The crack healing efficiency of the RPBCs is in the order of 92% as opposed to 9% for ACs. The RPBCs demonstrate much lower thermal sensitivity and better moisture resistance than the ACs. Potential area of application and limitation of the RPBCs were also Identified.

Materials and Structures, 2013

Waste materials recycling has been the logical and widely accepted means of conserving the dimini... more Waste materials recycling has been the logical and widely accepted means of conserving the diminishing global natural resources. This comes as a result of increased scarcity of raw industrial materials, coupled with environmental hazard of most of the waste products. In this paper, the effect of different waste material fillers, namely heavy oil fly ash (HOFA), coal fly ash, limestone dust, and cement kiln dust, and sulfur on the physical properties and performance of roofing and waterproofing asphalt has been examined. Conventional asphalt consistency tests in addition to a new bond strength test were conducted on the modified asphalt mastic. The results were analyzed statistically and assessed in accordance with ASTM D 332 and ASTM D 449 specifications. HOFA proved to be a superior filler additive compared to the other three additives. The sulfur mixes were found to be short on flash point values, but in spite of this, results show a promising potential alternative and cost effective material composite having the least amount of asphalt content.

Recycling as an economic disposal process for many hazardous waste materials has become a popular... more Recycling as an economic disposal process for many hazardous waste materials has become a popular means of conserving our planet's scarce and diminishing natural resources. This paper is a study of the influence of oil sludge (OS) on the physical behavior and performance of asphalt filled with heavy oil fly ash (HOFA), cement kiln dust (CKD) and limestone dust (LMD). Conventional asphalt consistency tests in addition to a new bond strength (BS) test were conducted on the modified asphalt mastics. The results were statistically analyzed and assessed in accordance with American Society for Testing and Materials (ASTM) D 332 and ASTM D 449 specifications. Too much OS resulted in strength deterioration of the asphalt mastic, which can be compensated for by filling the mastic with HOFA. OS interacts constructively with the fillers to improve their effectiveness in raising the softening point (SP) and viscosity of the asphalt, and also in reducing its penetration and ductility. Even though sludge mastics hold promise as suitable composites for damp proofing and waterproofing, the resulting low flash point (FP) and SP of some of these mastics make their suitability for roofing applications questionable.

Materials and Structures, 2013