Road Dust of Urban Landscape: A Case Study Insight
摘要
Urban local body (ULB) of Tumkur city, Karnataka, India adopts standard operating procedure for the cleaning of urban road dust (URD) from carriageway to enhance aesthetics of pavements. Thus, a comprehensive study focusing on (a) collection technique of the ULB, (b) independent URD collection, (c) URD physical and chemical properties, and (d) URD effect on friction characteristics of carriageway was initiated. The major limitations in ULB road dust cleansing activities were the data unavailability related to various attributes of the URD and mitigation strategies. To assess the URD characteristics, a manual sampling procedure was formulated and adopted on selected road stretches classified as (a) flexible pavement nonresidential (FNR), (b) rigid pavement nonresidential (RNR), (c) flexible pavement residential (FR), and (d) rigid pavement residential (RR). The parameters such as specific gravity, Atterberg limits, particle size distribution, and organic compounds were measured. The density of URD samples was in the range of 2.302–2.446. All the four URD samples were classified as silty sand with non-plasticity characteristics since the proportion of sand ranged between 72% and 78%. Oxidation state of fluvial organic carbon in URD was correlated to its chemical oxygen demand, which was found to be in the range of 57–206 mg O2/g URD. The study confirmed the presence of monobutyl phthalate, an organic compound within the family of phthalate esters and pharmaceuticals such as minocycline and lansoprazole in URD samples. The skid resistance of the four roads was measured in terms of British pendulum number (BPN). The descriptive statistics of the 184 BPN data points indicated the flexible pavements (FNR and FR) having microtexture characteristics while the rigid pavements (RNR and RR) were relatively slippery. Also, the deviation analysis indicated the movement and deposition of RD for a particular road type (i.e., rigid/flexible) significantly alters the sliding friction factor over a specified length of road.