Dust Palliatives Research Articles

Detection of the Butyl Acrylate–Vinyl Acetate (BA–VA) Copolymer in Soil Binders Using Gel Permeation Chromatography (GPC) and Nuclear Magnetic Resonance (NMR)

Dust palliatives are commonly used when airborne dust is problematic. Dry soils are treated with a mixture of polymers, such as butyl acrylate vinyl acetate (BA–VA), emulsified in water. Eventual spread through surface runoff or leaching may transport palliative away from the application area. This paper reports a novel method developed for the determination of BA–VA using gel permeation chromatography (GPC) and nuclear magnetic resonance spectroscopy (1H NMR) to provide qualitative and quantitative measurements allowing further investigation of polymer-based soil palliatives. The results showed that the average specific refractive index increments (dn/dc) for BA–VA copolymer in two dust palliatives were 0.055 and 0.038 mL/g. The masses of extracted BA–VA were 1400 and 2900 mg from these products. The corresponding limits of quantification (LOQ) for the extracted BA–VA polymer using a refractive index (RI) detector were 11.63 and 17.04 µg, respectively.

Analytical hierarchy process as dust palliative selection tool

ABSTRACTAnalytical hierarchy process (AHP) is a multicriteria decision-making tool with diverse applications. Previous studies indicated AHP can be used as a tool for infrastructure management including pavement management and pavement type selection. In this paper, the use of AHP as a dust palliative selection tool is introduced. Fugitive dust in unpaved roads is commonly controlled using various dust palliatives. There are different types of commercial dust palliatives available in the market. Selection of appropriate dust palliative that serves its function without compromising budget and environment is not an easy task. So far, several guidelines have been published for selecting appropriate dust palliative based on surface material type, traffic volume, climate condition and road geometry. However, based on these guidelines, it is likely to have more than one viable dust palliatives. These competing candidate dust palliatives should be compared among each other based on additional criteria to select the most appropriate of all. This can be done using the analytical hierarchy process. The use of AHP as a dust palliative selection tool is demonstrated in the paper using case study data and data from the literature.

Comparison of conventional and bio-treated methods as dust suppressants.

Dust is an environmental, geotechnical, health, and economical hazard. Fugitive dust emanating along transportation systems such as roads, railways, and airports especially can have significant impacts on health, safety, material loss, cost of maintenance, and interfere with the facilities. Quantitative studies on the effectiveness of the proper dust palliatives and their environmental impact have been studied with a number of biological and chemical methods. The objective of this study was to establish a method for using the microbial Induced calcium carbonate precipitation (MICP) approach to reduce the percent of mass loss against erosive force of wind regarding to the concentration and characteristics of aggregate used, climate, and traffic amounts. The results of this study showed that the required precipitation for dust control of sand by 70% is less than 15gCaCO3/m2 between sand grains in bio-treated sand. The wind tunnel test results of this study also indicate that the effectiveness of the bio-treatment method for dust control depends on many variables, such as the percent of precipitated calcium carbonate and tensile strength.

Safety risk interactions among highway construction work tasks

Recent research has produced frameworks for integrating safety risk data into project schedules, visual models and other construction planning tools. Unfortunately, only a few studies have attempted to quantify base‐level safety risk for construction tasks and no study has attempted to quantify the degree to which spatial and temporal interactions among tasks contribute to the potential for injury. A research study was performed to quantify the impact that pair‐wise spatial and temporal interactions have on the base‐level risk of 25 common highway construction work tasks in the United States. Six hundred risk interactions were quantified by obtaining and aggregating over 23 500 individual ratings from certified experts using the Delphi method. The results indicate that incompatible tasks may increase the base‐level risk up to 60%. The most incompatible highway construction tasks are: (1) installing curbs and gutters and installing rigid pavement; and (2) construction zone traffic control and installing rigid pavement. Additionally, watering and dust palliatives and pavement marking is the one compatible task pair and there are 45 neutral task pairs. The resulting database and analysis have the potential to increase the efficacy of existing frameworks for integration of safety risk data with project planning tools.

Investigation of Laboratory Procedure for Evaluating Chemical Dust Palliative Performance

An experimental testing protocol was developed to compare the relative effectiveness of chemical dust palliatives. The methods and application simulate field construction using commercial spray components. The test devices were constructed to simulate wind speeds and conditions for rotary wing aircraft. Fifteen chemical dust suppressants were evaluated using this methodology. These commercial products were applied topically to prepared soil specimens and allowed to cure for one and 48 h. Effectiveness was determined from the relative mass loss of the soil samples from erosion when samples were subjected to an air impingement device. An optical dust sensor was installed in the test device to measure airborne dust concentrations as an additional method for quantifying performance. A method to disturb the treated soil surface was also introduced to simulate the effect of traffic. Select application rates of the palliatives were used in sample preparation to identify minimal quantities necessary for the desired performance. The testing equipment and processes provided a rapid screening methodology for selecting potential dust palliatives. Results indicated good correlation between erosion and airborne dust concentrations with higher application rates and complete curing of materials demonstrating reduced dust levels. The traffic simulation test identified products with a propensity to form surface crusts that may be disturbed by traffic.

Full-Scale Testing of Chemical Dust Palliatives in a Semicontrolled Environment

Two commercially available chemical dust palliatives were evaluated in full-scale experiments in an enclosed, controlled environment to evaluate their effectiveness and to determine impacts to a stabilized surface. The dust palliatives were topically applied at multiple application rates to the surface of a silty sand soil that had been stabilized using a combination of Portland cement and polypropylene monofilament fibers. Simulated traffic was applied to enclosed test sections using the heavy vehicle simulator-aircraft fitted with a C-17 aircraft tire at 15,560 kg (34,300 lb) load. The effectiveness of the dust palliatives was quantitatively measured using both gravimetric and optical detection devices. Results from the experiment show nearly complete reduction in dust for Palliative 2 (a synthetic oil) and heavy applications of Palliative 1 (an emulsion polymer). The methodology used for experimentally determining the dust palliative effectiveness provided a mechanism for reducing environmental influences that often invalidate and confuse the results of field experimentation data.

Evaluation of Products and Application Procedures for Mitigating Dust in Temperate Climates

An evaluation of commercial dust palliatives was conducted to determine their effectiveness in mitigating fugitive dust on roads in temperate climates. Several types of dust palliatives were tested, including polymer emulsions, a polysaccharide solution, a calcium chloride solution, and synthetic fluids. Each product was placed in an individual test section; application rates ranged from 1.8 to 3.6 L/m2 with a topical or an admix construction method (grade, spray, till, compact, spray). Water-soluble products were diluted by using one part product and three parts water. Test sections were constructed and observed for 220 days to monitor product performance. Test sections were located along training routes at Ft. Leonard Wood, Missouri, and were subjected to heavy military truck and tracked vehicle traffic. Data from stationary and mobile particle collectors were analyzed to determine the ability of each product to suppress dust for extended periods. Nuclear density tests were performed to monitor soil moisture content and density. Several products are recommended for use on roads in temperate climates as a result of this evaluation.

Stabilization and Dust Control at the Buenos Aires National Wildlife Refuge, Arizona

The objective of this study was to evaluate road stabilizers and dust palliatives on a construction project of FHWA's Central Federal Lands Highway Division for long-term performance and to recommend products with acceptable performance for use on other projects. The evaluation addressed product performance for dust control, rutting, washboarding, raveling, material stabilization, and cost-effectiveness. Roadway stabilization or dust abatement products are classified into the following seven categories: water, water absorbing, organic petroleum, organic nonpetroleum, electrochemical, synthetic polymer, and clay additives. Six soil stabilizers were applied, each on a 1.6-km (1-mi) section to a depth of 150 mm (6 in.) at the Buenos Aires National Wildlife Refuge in south central Arizona, and were monitored at 6-month intervals for 2 years. Visual evaluation included effectiveness in controlling dust, washboarding, and raveling. Physical evaluation included moisture and density, gradation, liquid limit, plastic limit, R-value, California bearing ratio, and silt loading. Analysis included an overall ranking of the six materials and their performance. All products performed well for this semiarid desert location and nonplastic roadway material. The best-performing group had two organic nonpetroleum plus water-absorbing combination products. The second group had one water-absorbing and one organic nonpetroleum product. The third group had two electrochemical products and one synthetic polymer product.

Development of Performance-Based Tests for Nontraditional Road Additives

Nontraditional road additives (chemical stabilizers and dust palliatives) are applied to unsealed roads to reduce dust levels and gravel loss and improve riding quality and all-weather passability. However, the level of research conducted on additives and documentation derived from it are often unsatisfactory. A review of studies revealed that similar procedures were followed, which entailed routine laboratory tests on a locally available material, followed by a field test during which the period of effectiveness was assessed. No documented test methods exist specifically for these additives. Researchers tend to adapt methods developed for cementitious and asphaltic additives or compare before- and after-treatment results on standard indicator tests. Results rarely correlate with field performance, necessitating construction of full-scale experiments before making a decision on applying the additives on a wider scale. Invariably, a new experiment must be constructed each time conditions such as material, traffic, and climate change. A series of performance-based laboratory tests for nontraditional road additives has been developed, and results have been compared with performance in full-scale experiments. Results are compared with untreated controls or traditional stabilizers. The tests have been incorporated into a research protocol as well as a fit-for-purpose certification system for road additives. They are sensitive enough to assess performance at different application rates and to compare the performance of different additives on the same material. Tentative limits for decision making have been developed on the basis of comparisons of test results with performance on full-scale sections.

Evaluation of Dust Palliatives for Unpaved Roads in Arid Climates

An evaluation of commercial and experimental dust palliatives was conducted to determine their effectiveness for mitigating fugitive dust on roads in arid climates. Several types of chemicals were tested including polymer emulsions, lignosulfonates, chloride salts, synthetic fluids, an asphalt emulsion, a polysaccharide solution, a polyacrylamide, and a guar gum. Each product was placed in an individual test section at a rate of 3.8 L∕ m2 using an admix construction method (grade/spray/till/compact/spray). Fourteen test sections were constructed and observed at 30-day intervals to monitor product performance. Data from both stationary and mobile particle collectors were analyzed to determine the ability of each product to suppress dust for extended periods. Several products are recommended for use on roads in arid climates as a result of this evaluation.

New method to measure control performance of dust palliatives on unpaved roads at federal facilities

AbstractMilitary training activities often produce significant dust emissions from unpaved travel surfaces. Because failure to comply with environmental regulations could adversely affect training operations, prudent use of chemical palliatives for control of dust from unpaved surfaces enhances the Army's land‐based training capability, mission, and combat readiness.This article describes a new, more efficient method to determine the control effectiveness of palliatives on roads at Army facilities. Rather than attempting to quantify “absolute” emission rates, the “mobile sampler” described in this article relies on relative measures. As compared to the methods used in previous field studies, the mobile sampler is not only more efficient in terms of time and labor required, it also provides greater reproducibility and relieves many of the restrictions placed on acceptable test sites when using test methods for absolute emission levels. © 2003 Wiley Periodicals, Inc.

Toward Fit-for-Purpose Certification of Road Additives

Chemical stabilizers and dust palliatives are widely used in road construction and maintenance to improve the characteristics and performance of available materials for lower dust levels, improved riding quality, reduced gravel loss, and improved all-weather passability. Numerous products are available to the road industry. However, the level of research and the usefulness of the findings differ from product category to product category. In many instances, no effort has been made to quantify the benefits and cost-effectiveness of additives over longer periods of time (e.g., 5 years), and little attempt has been made to compare the performance of treated roads with the performance of untreated roads for reduced gravel loss and reduced maintenance, the two most important factors in unsealed road management. Only limited information on material requirements and application techniques is available, whereas there is minimal information on rejuvenation. This lack of understanding has culminated in general skepticism in the road industry regarding chemical dust control and stabilization with so-called alternative stabilizers. The situation is aggravated by poor marketing, with many sales representatives having no engineering background, little understanding of the road industry, and insufficient information to provide adequate technical backup. Discussions with road authorities and consulting engineers indicated that a “fitfor-purpose” certificate for each product issued by an independent certification body would contribute to confidence in the use of the products. A certification system would also encourage suppliers to conduct appropriate product research. An internationally recognized certification body in South Africa was therefore approached about developing such a certification system, under the guidance of a steering committee with representation from road authorities, consulting engineers, product suppliers, and academia. Unsealed road additive certification is introduced, the development of control tests for certification is detailed, and a procedure for certification is proposed.

Laboratory Study of Dust Palliative Effectiveness

Three different aggregate types were treated with water and two commercially available dust palliatives and tested in the laboratory to quantify their resistance to erosion by wind and traffic. Treated and untreated specimens were subjected to a simulated wind velocity of 32 KM/h in a wind tunnel to examine resistance to wind erosion. In a second test, different specimens were subjected to up to 1,500 simulated traffic applications to measure resistance to traffic erosion. Material and environmental variables considered in the testing program include curing temperature, curing period, palliative concentration, and application rate. Results obtained confirm that dust palliatives can significantly reduce erosion of low-volume unpaved roads and that the effectiveness of a particular palliative depends on soil type, traffic loads, and environmental conditions. A parametric study was also conducted to establish palliative selection criteria. The laboratory testing program developed and the selection criteria identified can be used as a decision-making tool to select an effective dust palliative for a particular soil type and environment.

Holistic Approach to Research into Dust and Dust Control on Unsealed Roads

Aspects of dust and dust control have been studied for many years in most countries with unsealed road networks. However, no comprehensive coordinated study to investigate the processes affecting the generation of road dust, road dust measurement, road dust prediction, acceptability criteria for dust, or the performance of dust palliatives has been undertaken. Over the past 6 years, the Council for Scientific and Industrial Research has been engaged in such a study. Although research has been undertaken on behalf of numerous parties, experimental designs have been coordinated in an attempt to develop guidelines for the responsible use of dust palliatives. Unfortunately, many of the experiments that have been undertaken by product manufacturers and road authorities over the years have been uncoordinated and poorly monitored, with minimal information being recorded or published. Many of these experiments have failed, with the product always being blamed, and this, together with poor marketing techniques used by suppliers, has led to skepticism by the roads industry toward the use of the products. Scientific research, following detailed experimental designs, funded by the product suppliers has resulted in the development of guidelines for the use of certain products. Studies have shown that, provided the products are used under appropriate circumstances, they can provide a cost-effective interim measure to improve the quality of life and preserve construction materials until such time as the road can be upgraded to a sealed surface. The holistic approach to dust and dust control research that has been followed is discussed here, a summary of the findings is described, and recommendations toward implementing a dust-control program are made.

The Use of Water, Calcium Chloride, Light Oils, etc., as Dust Palliatives

In the discussion of this topic the element of road preservation is excluded, except in so far as the use of the materials described may incidentally affect that problem. The field for discussion, therefore, is a narrow one, confined principally to the relative merits and economy of the various materials for allaying dust.