Improving mine haul road performance through innovative material treatment using Nano-Modified Emulsions (NME’s)

Qacha, Bohlajana (2022-04)

Thesis (MEng)--Stellenbosch University, 2022.

Thesis

ENGLISH ABSTRACT: Mine haul roads require reliable riding quality for optimally low transport costs and truck mainte nance. This is part of functional, structural, and pavement management systems. The extremely heavy traffic, environment (heavy rains), spillage of ore all contribute to the need of improving the design life of haul roads. Soil mineral phase analysis is a necessary test to understand the contribu tion of minerals within the aggregates to withstand the load-bearing requirements. More recently nanotechnology related to the stabilization of the load-bearing layers e.g., NME’s (Nano-Modified Emulsions) have improved the strength and durability of haul road layers. The efficiency of the NME’s depends on the mineralogy and requires chemical testing to evaluate the efficiency of the existing aggregate. This study determines the effectiveness of organosilane compounds to improve mechanical prop erties, strength, hydrophobicity, and load-load bearing capacity of haul road base construction materials. Mechanical tests are key to understanding the performance of nano modified materi als. For this project, mineralogy test samples include untreated and treated materials of both the crushed stone and Laterite aggregates from the Zambian Copperbelt. The expectation is to identify both primary and secondary minerals present in the aggregates and their composition. To evaluate shear strength and permeability of treated and untreated materials. This will enable the prediction of the aggregates’ behaviour. The selected additives include nano silanes and modified bitumen and need to be benchmarked against untreated materials. Research results indicate that organosilane compounds influence strength and water ingress in un bound granular materials particularly crushed stone. Small amounts of organosilane compounds offer optimum mix performance. Lime addition results in a decrease in tensile strength in all material mix designs. Mix components compatibility influences the effectiveness of stabilisation. Blending organosilane compounds into bitumen emulsion is an optimum incorporation mechanism, although this may depend on available equipment and aggregate types. There is decreased moisture ingress or hydrophobic properties on nano modified granular materials. In dry conditions natural aggregates and crushed stone show high strength.

AFRIKAANSE OPSOMMING: Mynvervoer paaie vereis betroubare rygehalte vir optimaal lae vervoerkoste en onderhoud van vragmotors. Dit is deel van funksionele, strukturele en plaveiselbestuurstelsels. Die buitengewone swaar verkeer, Natuurelemente (swaar reën), mors van erts, dra alles by tot die verbetering van die ontwerp lewe van mynvervoer paaie. Kwalitatiewe ontleding van grondmineraal is ’n noodsaaklike toets om die bydrae van minerale in die aggregate te verstaan om aan die lasvereistes te voldoen. Meer onlangs het nanotegnologie wat verband hou met die stabilisering van die draende lae, bv.NME (Nano-gemodifiseerde Emulsies) die sterkte en duursaamheid van die vervoerpaaie verbeter. Die doeltreffendheid van die NME’s hang af van die mineralogie en vereis chemiese toetsing om die doeltreffendheid van die bestaande aggregaat te evalueer. Hierdie studie bepaal die doeltreffendheid van organosilaanverbindings om meganiese eienskappe, sterkte, hidrofobisiteit en die dravermoë van die konstruksiemateriaal van die padbasis te verbeter. Meganiese toetse is die sleutel tot die begrip van die werkverrigting van nano-gemodifiseerde materiale. Vir hierdie projek bevat mineralogie-toetsmonsters onbehandelde en behandelde materiale van beide die fyngemaakte klip- en Latreietaggregate van die Zambiese Copperbelt. Die verwagting is om primˆere en sekondˆere minerale wat in die aggregate en die samestelling daarvan voorkom, te identifiseer. Om die skuifsterkte en deurlaatbaarheid van behandelde en onbehandelde materiale te evalueer. Dit sal die voorspelling van die aggregaat se gedrag moontlik maak. Die geselekteerde bymiddels bevat nano-silane en gemodifiseerde bitumen en moet vergelyk word aan onbehandelde materiale. Navorsingsresultate dui daarop dat orgaanosilaanverbindings die sterkte en die waterindringing be¨ınvloed in ongebonde korrelmateriaal, veral fyngemaakte klip. Klein hoeveelhede organosilaanverbindings bied optimale mengselprestasie. Die byvoeging van kalksteen lei tot die afname in trek terkte in alle materiaalmengsels. Verenigbaarheid van mengkomponente be¨ınvloed die doeltreffendheid van stabilisering. Die vermenging van organosilaanverbindings in bitumen emulsies is ‘n optimale inskakeling meganisme, alhoewel dit mag afhang van die beskikbaarheid van toerusting en aggregaat tipes. Daar is ’n verminderde vogindringing of hidrofobiese eienskappe op nano gemodifiseerde korrelmateriaal. In droe toestande toon natuurlike aggregate en fyngemaakte aggregaat hoë sterkte.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/124665
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