Browsing by Author "Nikraz, H"

Now showing 1 - 3 of 3

item: Conference-Abstract
Laboratory study of lime kiln dust as a moisture damage reducing agent in dense graded asphalt concrete mixture
(2019) Dammika, HTR; Sarukkalige, R; Biswas, W; Nikraz, H
Road authorities are experiencing a considerable degree of moisture associated distresses such as ravelling and stripping, on flexible pavements. Therefore, it is required to modify asphalt concrete (AC) mixtures to have higher moisture damage resistance. Previous studies have shown that hydrated lime (HL) increases the resistance to the adverse effect of water in the AC mixture. But it has limited usage as it is expensive. The first part of this research project confirmed that lime kiln dust (LKD) is a good substitute for HL as an effective mineral filler in AC mixture and 50% LKD of bitumen binder mass gives the optimum performance. This paper addresses the use of LKD as moisture damage reducing agent in Dense Graded Asphalt (DGA). Stripping potential of LKD was investigated to ensure sustained adhesion between bitumen and aggregates in instances where pavement saturation is evident. Tensile strength ratio (TSR) and resilient modulus ratio (MrR) were used to predict the moisture resistance of DGA mixture and studied the long-term aging effect on those parameters. TSR test was conducted according to the modified Lottman test method and MrR test was performed using the indirect tensile method on mixtures with LKD, HL, and control mix. The test specimens were prepared with an air void ratio of 8±1%. Mixtures with LKD and HL have satisfied Austroads and super-pave mix design specifications which is TSR> 80% and MrR>70% for low moisture susceptibility. LKD and HL mixtures have shown more than 100% for both TSR and HL because the presence of these filler materials cause to enhance adhesion and cohesion bonds within the mixture when water exists. LKD behaves almost the same as HL and provides well resistance for moisture associated fatigue cracking and wheel path rutting deteriorations regardless of the aging conditions. Overall, LKD is excellent moisture damage reducing agent.
item: Conference-Extended-Abstract
Laboratory study of the effect of long-term aging and temperature on resilient modulus of dense graded asphalt concrete with lime kiln dust
(2019) Dammika, HTR; Sarukkalige, R; Nikraz, H
The flexible pavements are highly vulnerable to surface damage due to an increase in temperature, excessive load, moisture and aging of asphalt mixes. They should have high engineering and structural performance to have a maximum service life. Resilient Modulus (Mr) is the stiffness or a measure of cohesion of asphalt concrete (AC) mixture. It is an important parameter in pavement design and plays a vital role in flexible pavement durability. Stiffness of an AC mixture is varying with temperature and long-term field condition. Previous researches proved that Lime Kiln Dust (LKD) performs well as a mineral filler and moisture damage reducing agent in Dense Graded Asphalt (DGA) mixture. This paper highlights how LKD effects on the stiffness of DGA mixes with the variation of temperature and aging. Mr is measured by using the indirect tensile method under aged and unaged conditions at 20 oC and 40 0C temperatures. The study was done on DGA 10 and DGA14 mixtures with hydrated lime (HL), LKD and no additive (control mix). SHRP long-term oven aging (LTOA) was used for aging specimens to represent 15 years of field aging in a Wet-No-Freeze climate and 7 years in a Dry-Freeze climate. This research found that LKD and HL based mixtures perform almost the same when considering the effect of aging and temperature on Mr. Stiffness of all mixtures decrease when temperature increases and increase with aging. LKD provides more stiffness to DGA mixtures than HL under long term aging condition. LKD based mixtures show minimum stiffness reduction with the temperature increasing. Therefore, it can be concluded that LKD is an excellent mineral filler that can be used as a substitute for HL to enhance the performance of DGA mixture in terms of high temperature and excessive loading.
item: Conference-Full-text
Sustainable use of construction and demolition (C&D) waste as A road base material
(2013-11-15) Batmunkh, N; Siripun, K; Jitsangiam, P; Nikraz, H
Crushed concrete waste is a by-product from building demolition and constitutes a principal component of municipal solid waste consisting of concrete, sand, brick, rock, metals and timber. Over 50% of this waste is commonly sent to land-filled sites, resulting in the impact on the limited capacity of land-filled sites. Nowadays, the sources of virgin natural aggregates are depleted by increasing in demand of using a virgin material in building and infrastructure construction and maintenance facilities. This depletion leads to the utilisation of crushed concrete waste to replace natural aggregates in road and highway construction. Of key significance of this study is to present alternative materials for road and highway construction on the production of the proper guideline for road base by using crushed concrete waste. Sophisticated tests were conducted to investigate the mechanical responses of compacted crushed concrete subjected to applied loads simulated from traffic loads. Unconfined compressive strength, shear strength parameters, resilient modulus and permanent deformation of such material were determined. Our findings showed that crushed concrete waste is able to utilise as a road base material. The results of this study will enhance increased use of crushed concrete waste in road and highway construction and will, therefore, alternatively reduce consumption and costs in manufacturing virgin aggregates.