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21 results on '"Byzyka, Juliana"'

3. Fundamental characterisation of thermal influence in hot mix asphalt repair

Author

Byzyka, Juliana, Rahman, M., and Tai Wan, K.

Subjects
625.8, Asphalt pavement failures, Pothole repair interface disintegration, Infrared heat, Thermal finite element modelling
Abstract

The study focuses on the issue of hot mix asphalt pothole repairs, the performance of which is greatly reduced by repair edge disintegration. This is caused by low interface temperatures which result in low density interfaces and poor repair bonding. The study examined heat flow in shallow and deep pothole excavations under controlled pre-heating done in heating-cooling cycles, referred as "dynamic heating", and the effect of asphalt thermal properties on this. Dynamic heating was applied with an experimental infrared heater operating between 6.6 kW and 7.7 kW heat power and with the heater being stationary or moving above simulated potholes at offsets of 130 mm and 230 mm. The study also examined heat flow in traditional non-heated shallow repairs, referred as "static repairs", and dynamic shallow repairs and the effect of pothole pre-heating in repair adhesion. Finite Element modelling was also used to enhance understanding of heat flow in the executed repairs. Then, the bonding properties and rutting resistance of the repairs were assessed using shear bond tests (SBT's) and wheel track tests (WTT's) respectively. The results showed that irrespective of excavation depth, heating power and heater offset, temperature distribution in the pothole excavation and inside the slabs under dynamic heat was non-uniform. Dynamically heating pothole excavations for approximately 10 minutes yields better heat distribution than 20 minutes heating time while minimising the possibility of asphalt overheating. The temperature profile at the interface of the dynamically heated repair is improved when compared to static repair suggesting better interface adhesion. A significant role in this profile is played by thermal contact conductance which determines the resistance to pavement-repair thermal conduction per unit area at the repair interface. This was reflected in the assessment and simulation of the repairs with the latter generating reasonable transient temperature profiles within the dynamically heated pothole excavation, at the interface of the repairs, and inside the host pavement. Further, the shear strength at the bottom and side interfaces of dynamically heated repairs was 78.2% and 68.4% higher respectively than that of static repairs. On average, static and dynamic repairs showed repair interface rutting depths of 14.82 mm and 10.36 mm respectively. It was concluded that dynamically heating a pothole excavation increases repair interface adhesion and repair durability.

Published
2018

17. Thermal Analysis of Hot Mix Asphalt Pothole Repair by Finite-Element Method

Author

Byzyka, Juliana, Rahman, Mujib, and Chamberlain, Denis

Abstract

Traditional repair methods tend to suffer from inadequate net interface heating because the combined effect of placing hot fill mix in a cold, old pavement leads to inadequate net temperature levels. The outcome of this is low durability and limited life. In contrast, the outcome of placing hot mix in a controlled, preheated host pavement is substantial increased working life. To understand repair heating, this study ran heat transfer finite-element models for the cases of (1) hot mix asphalt (HMA) placed in an ambient temperature pothole, (2) the heated pothole recess, and (3) HMA placed in the preheated pothole recess. The air–pavement–heater system model comprises a host pavement with two pothole repairs or, in the case of the second thermal model, with one empty pothole excavation, and an infrared heating element plate. For calibration purposes, experimental work of simulated repairs undertaken in previous research was used. The air–pavement–heater system setup followed an optimum pothole preheating method also determined in previous research. Thermal models were validated with previous experimental work. It was concluded that the models generate reasonable transient temperature profiles within the dynamically heated pothole excavation, at the interface of the repairs, and inside the host pavement.

Published
2020

20. An improved interface temperature distribution in shallow hot mix asphalt patch repair using dynamic heating.

Author

Byzyka, Juliana, Rahman, Mujib, and Chamberlain, Denis Albert

Subjects
*TEMPERATURE distribution, *ASPHALT, *LOW temperatures, *THERMAL resistance, *GUTTA-percha
Abstract

This study focuses on the issue of hot mix asphalt patch repairs, the performance of which is greatly reduced by repair edge disintegration. This is caused by low interface temperatures which result in poor repair bonding between fill material and host pavement. Twenty-four pothole repairs, 45 mm in depth, comprising 12 static and 12 dynamic repairs heated for 10 min 15 s and 21 min 49 s, respectively have been investigated. Dynamic heating has been completed using an experimental infrared heater. Temperatures were measured at 11 locations on the repair interfaces during the pouring and compaction of the fill mix. Volumetric of asphalt mixtures were also investigated. The results demonstrated that for static repairs, the lowest maximum temperatures were located at corners and on vertical repair boundaries. It was found that high thermal contact resistance in these interfaces dramatically affect the temperature levels. However, the figures improved in dynamically heated repairs. Comparing dynamically heated repairs of 10 min 15 s and 21 min 49 s with static repairs, showed average corner temperatures increase 10.85–24.45°C and 29.51–36.73°C, respectively, with accompanying increases in vertical interface temperatures 34.97°C and 46.41°C, respectively. [ABSTRACT FROM AUTHOR]

Published
2020
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