Browsing by Author "Wickramarachchi, P"

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    item: Conference-Full-text
    Enhanced Performances for Marshall Properties of Hot Mix Asphalt (HMA) by Incorporated 60/70 Grade of Bitumen
    (2016-01-06) Wickramarachchi, P; Udith, HLDMAJ; Perera, D; Priyashantha, K
    During the last decade, the rehabilitation and improvements of road networks in Sri Lanka exhibited a rapid development. As a result many of roads were undergone for new asphalt surfacing with hot mix asphalt, at least a wearing course, and the black top. However, with this rapid development, few premature failures were also observed in many of these newly constructed asphalt roads covering all part of Sri Lanka. Pre-mature cracking, removal of top thin film of wearing layer, bleeding and localized failures were among them. Bitumen played a very important role in hot mix asphalt and improvement for bitumen can enhanced the improved properties of HMA significantly. In this research, instead neat 60/70 grade of bitumen, it was used modified 60/70 grade, with Nano silane, enhancing anti-stripping and bonding capabilities. Research was comprised three stages of testing, lab trials, plant trials and filed trial in Colombo- Kandy road section. Results showed significant improvement for marshal properties. The stability and flow increased by 24% and 35 %, respectively. The anti-stripping property was also increased significantly, even after 6 hr, boiling test, it showed elevated no of coated aggregates. In addition, the mix was very well after few weeks, and very sticky condition proved that the strong bonding ability. All enhanced characteristics can be caused to exhibit improved performance and can be lead to extended life period of road construction.
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    item: Article-Abstract
    Gas transport parameters for compacted reddish - brown soil in Sri Lankan landfill final cover
    Wickramarachchi, P; Ranasinghe, K; Hamamoto, S; Kawamoto, K; Nawagamuwa, UP; Moldrup, P; Komatsu, T
    Gas exchange through (he compacted final cover soil at landfill sites plays a vital role for emission, fate, and transport of toxic landfill f,ases. This study involved measuring the soil-gas diffusivity tDp/Du, the ratio of gas diffusion coefficients in soil and free air) and air permeability (k,J for differently compacted soil samples (reddish-brown soil) from the final cover at the Maharagama landfill in Sri Lanka. The samples were prepared by either standard Proctor compaction or hand compaction to dry bulk densities of 1.60-1.94 g cm='. Existing and modified models for predicting Dp/ Do and k" were tested against the measured data. The simple, single-parameter Buckingham model predicted measured Dp/ Do values across compaction levels equally well or better than a dry bulk density (DBD) dependent model and a soilwater retention (SWR) dependent model. The measured ku values for differently compacted samples were highly affected by the compactionlevel and the sample moisture preparation method. Also, for air permeability, a single-parameter Buckingham-type k" model was most accurate in predicting k" in the differently compacted soil samples. Equivalent air-filled pore diameters