Geotextile separators for dust suppression on gravel roads

Dust can be a health concern because of its potential to contain respirable particles. The US Environmental Protection Agency (EPA) designates particulate matter of 10 microns or less in diameter (PM 10) as the point of regulatory concern. Dust can also be a nuisance issue for residents living in the vicinity of gravel roads. The US EPA and state environmental agencies developed and implemented a reporting system for the amount of particulate (PM 10) derived from various sources including gravel roads. An annual fee is assessed to the roadway owners based on the estimated level of particulate generated from the roadway per year. Dust control treatments such as watering the gravel road or applying a dust suppressant reduce the annual fee. Although numerous techniques are used in attempts to control the dust generated from gravel roads, all have limitations and the search for more effective means of reducing dust levels from gravel roads continues. Geotextile separators offer the potential to reduce dust while providing enhanced driving characteristics and reduced maintenance of the roads.; A field demonstration program was initiated to quantitatively document the dust suppression effect of geotextile separators on unpaved, gravel-surfaced roads. Active monitoring systems were used to collect and quantify dust volumes and particulate size distributions along with distance of transport and vehicular characteristics. The test site was located in Boone County, Missouri and was approximately 180 m in length by 15 m in width. It included two, 100-m nonwoven geotextiles (AASHTO Class 2) test sections and a 100-m control section (fresh gravel with no geotextile). One geotextile was spun bonded and the other was needle punched.; Six sampling events were taken to evaluate the effectiveness of using geotextiles as a dust suppressant. Two sampling events were taken before the geotextiles were installed and are identified as pre-geotextile sampling events. Four sampling events were taken after the geotextiles were installed and are identified as post-geotextile sampling events.; Results indicated that the dust collected on the downwind side were always significantly higher than the dust collected on the upwind side. Initially, dust collected on the control section was 70 to 80% less than the pre-geotextile dust levels, for the downwind side. Over a five month period the dust levels in the control section increased and the range was 80% to 230% of the pre-geotextile dust levels. Dust levels from the spun bonded geotextile section ranged from 10% to 310% of that from the control section; while dust from the needle punched geotextile section ranged from 20% to 190% of that from the control section. Analyses were conducted on the surface aggregate. Results indicated that the aggregate used to surface the road was readily soluble.; The objective of this research was to determine the effectiveness of geotextile separators on reducing dust from gravel roads. Installing a geotextile on unpaved roads was determined to be beneficial in reducing the dust. A direct relationship was observed between the amounts of fines in the surface aggregate to the use of geotextiles. Comparing the control section to the geotextile sections indicated that there was an increase in the amount of fines in the control section, this increase in fines was likely due to the fines coming from the subbase material.