Dust Control Using an Asphalt Emulsion, HR-196, 1977

In an effort to control fugitive dust on a gravel surfaced roadway in Boone County, a cationic asphalt emulsion was blended with warm water and applied with an asphalt distributor. The test included various application procedures. After visual observations, it was concluded that this procedure utilizing a dilute asphalt emulsion was not an effective method of dust control.

Asphalt Emulsion Bound Macadam in Dubuque County, Iowa, HR-216, Construction Report, 1981

This construction report describes a project investigating macadam base construction of roads. The objectives of this project were to: 1. identify a cost effective asphalt emulsion bound macadam typical cross section; 2. obtain useful data comparing seven typical cross sections; 3. determine the effectiveness of engineering fabric placed under macadam roadbeds; and 4. evaluate the use of emulsions in surface seal coats.

Asphalt Emulsions for Highway Construction, HR-216, 1985

A 5.8 mile section of Dubuque County (Iowa) Road D-53 was selected for this project, the objective of which were to: 1. identify a cost effective asphalt emulsion bound macadam typical cross section; 2. determine the effectiveness of engineering fabric placed under macadam roadbeds; and 3. evalaute the use of emulsions in surface seal coats. A number of conclusions were reached: 1. The minus #200 sieve material for the macadam stone should be held to a minimum. For the emulsion used on this project, the minus #200 material had less than 4 percent to achieve satisfactory coating of the macadam stone. 2. The placement of the emulsion treated macadam required no additional equipment or time than the plain macadam placement. 3. Emulsion treating the macadam stone for the shoulder base appears unnecessary. 4. The emulsion treated macadam base beneath an asphaltic concrete wearing surface yielded a higher structural rating than the plain macadam beneath a comparable ashaltic concrete surface. 5. The performance of the fabric between the subgrade and the macadam base to prevent soil intrusion into the base could not be determined by the non-destructive testing conducted. 6. When no choke stone is used over the macadam base, allowance for ac mix overrun should be made. 7. Use of an emulsion instead of a cutback asphalt saved money and energy. However, the poor performance of the seal coat negated any real savings.

Asphalt Binders for Thin Maintenance Surfaces, TR-435, 2003

Asphalt is used as a binder for thin maintenance surface (TMS) applications because of two key properties, it is waterproof and it adheres relatively well to the aggregate. Since asphalt is too stiff at room temperature to apply to the road surface, it is usually applied as either a cutback asphalt or an asphalt emulsion. The asphalt emulsions can be further divided into high float emulsions, cationic emulsions or polymer-modified binders, which are emulsions with polymers added to them. These types of binders are discussed further below.

Implementation package : emulsified asphalt-aggregate mixtures-mix design and design coefficients.

"April 1981."

Effect of bituminous impregnation on nonwoven geotextiles tensile and permeability properties

Geosynthetics interlayer systems are effective techniques to control reflective cracking in damaged pavements. It comprises the inclusion of nonwoven geotextiles between the damaged layer and the new overlay of the pavement to reduce the propagation of cracks and to extend pavement life. However, the success of this technique depends directly on the understanding of the geotextile`s behavior when impregnated with asphalt This paper evaluates different nonwoven geotextiles frequently used in anti-reflective cracking systems, focusing on initial stiffness gain and permeability reduction after asphalt impregnation. Fresh and impregnated samples of polyester and polypropylene nonwoven geotextiles were tested. Cationic rapid setting emulsified asphalt was used as asphalt binder. Wide-width tensile tests were carried out based on the specification of ABNT - NBR 12824 (1993). Water vapor transmission tests were conducted according to ASTM E 96M (2005). Results of tensile tests on impregnated geotextiles showed a significant increase on tensile strength values, probably due to the inter contact of the fibers. Results also showed high increase in strength values at strain levels less than 0.05% and decrease on stiffness gains with increase of strains. Water vapor transmission tests demonstrated that cationic asphalt emulsion applied on nonwoven geotextiles allows a drastic reduction in permeability values to turn nonwoven geotextiles into a low permeability barrier. (C) 2010 Elsevier Ltd. All rights reserved.

Laboratory Study of Slurry Seal Coats, HR-185, Revised, 1978

Extensive programmed laboratory tests involving some 400 asphalt emulsion slurry seals (AESS) were conducted. Thirteen aggregates including nine Iowa sources, a quartzite, a synthetic aggregate (Haydite), a limestone stone from Nebraska, and a Chat aggregate from Kansas were tested in combination with four emulsions and two mineral fillers, resulting in a total of 40 material combinations. A number of meetings were held with the Iowa DOT engineers and 12 state highway departments that have had successful slurry seal experiences and records, and several slurry seal contractors and material and equipment suppliers were contacted. Asphalt emulsion slurry seal development, uses, characteristics, tests, and design methods were thoroughly reviewed in conjunction with Iowa's experiences through these meetings and discussions and through a literature search (covering some 140 articles and 12 state highway department specifications). It was found that, while asphalt emulsion slurry seals (when properly designed and constructed) can economically improve the quality and extend the life of existing pavement surface, experiences with them had been mixed due to the many material, slurry, and construction variables that affect their design, construction, and performance. The report discusses those variables identified during the course of the project and makes recommendations concerning design procedures, design criteria, specifications and the means of evaluating them.

Field Performance and Evaluation of Slurry Seals, HR-195, 1980

As part of the overall research program of evaluating asphalt emulsion slurry seal as a pavement maintenance material, 31 duplicate 500-ft test sections were constructed on U.S. 6 between Adel and Waukee in Dallas County during September and October of 1978. These test sections included combinations of eight aggregates, two gradings, three asphalt emulsions, two mineral fillers, and a range of emulsion contents determined by laboratory mix designs. The emulsion contents of the test sections varied from 10.3% for Section 7A (Ferguson coarse) to 32.9% for Section 31A (lightweight aggregate). The post-construction performance evaluation of the test sections, consisting primarily of the friction tests and surface appearance observations, was conducted at different time intervals up to 24 months after construction. At the 24-month final evaluation, most of the test sections had carried a total of 1.4 million vehicles.

Obtenção de emulsões asfálticas convencionais e modificadas com argilas e nanoargilas

The increasing demand for asphalt leads to the development of techniques that can improve the quality of products and increase the useful working life of pavements. Consequently, there is a growing application of asphalt emulsions, which are produced from a mixture of petroleum asphalt cement (CAP) with an aqueous phase. The main advantage of asphalt emulsions is its cold application, reducing energy costs. Conventional emulsions are obtained using asphalt, water, solvent, and additives. The modified asphalt emulsion is developed by adding a modifying agent to conventional emulsions. These modifiers can be natural fibers, waste polymers, nanomaterials. In this work modified asphalt emulsion were obtained using organoclays. First, it was prepared a conventional asphalt emulsion with the following mass proportion: 50% of 50/70 penetration grade CAP, 0.6% of additives and 3% of emulsifier, 20% of solvent and 26.4% of water. It was used bentonite and vermiculite (1% and 4%) to obtain the modified asphalt emulsion. Bentonite and vermiculite were added in its raw state and as an organoclay form and as an organoclay-acid form, resulting in 26 experimental runs. The methodology described by Qian et al. (2011), with modifications, was used to obtain the organoclay and the organoclay-acid form. infrared spectroscopy (IR)) were used to characterize the clays and nanoclays. The emulsions were prepared in a colloidal mill, using 30 minutes and 1 hour as mixing time. After, the emulsions were characterized. The following tests were performed, in accordance with the Brazilian specifications (DNER- 369/97): sieve analysis, Saybolt Furol viscosity, pH determination, density, settlement and storage stability, residue by evaporation, and penetration of residue. Finally, it can be concluded that the use of nanoclays as asphalt modifiers represent a viable alternative to the road paving industry

Obtenção de emulsões asfálticas modificadas utilizando resíduos industriais

The main objective of this research was the development and characterization of conventional and modified cationic asphalt emulsions. The asphalt emulsions were developed by using the Petroleum Asphalt Cement (CAP 50-70) from Fazenda Belém (Petrobras -Aracati-Ce). The first step in this research was the development of the oil phase (asphalt + solvent) and the aqueous phase (water + emulsifying agent + acid + additives), separately. During the experiments for the obtaining of the conventional asphalt emulsion, the concentration of each constituent was evaluated. For the obtaining of the oil phase, kerosene was used as solvent at 15 and 20 wt.%. For the development of the aqueous phase, the emulsifying agent was used at 0.3 and 3.0 wt.%, whereas the acid and the additive were set at 0.3 wt.%. The percentage of asphalt in the asphalt emulsion was varied in 50, 55, and 60 wt.% and the heating temperature was set at 120 °C. The aqueous phase in the asphalt emulsion was varied from 16.4 to 34.1 wt.% and the heating temperature was set at 60 °C. After the obtaining of the oil and the aqueous phases, they were added at a colloidal mill, remaining under constant stirring and heating during 15 minutes. Each asphalt emulsion was evaluated considering: sieve analysis, Saybolt Furol viscosity, pH determination, settlement and storage stability, residue by evaporation, and penetration of residue. After the characterization of conventional emulsions, it was chosen the one that presented all properties in accordance with Brazilian specifications (DNER-EM 369/97). This emulsion was used for the development of all modified asphalt emulsions. Three polymeric industrial residues were used as modifier agents: one from a clothing button industry (cutouts of clothing buttons) and two from a footwear industry (cutouts of sandals and tennis shoes soles), all industries located at Rio Grande do Norte State (Brazil).The polymeric residues were added into the asphalt emulsion (1 to 6 wt.%) and the same characterization rehearsals were accomplished. After characterization, it were developed the cold-mix asphalts. It was used the Marshall mix design. For cold-mix asphalt using the conventional emulsion, it was used 5, 6 and 7 wt.% asphalt emulsion. The conventional mixtures presented stability values according Brazilian specification (DNER-369/97). For mixtures containing asphalt modified emulsions, it was observed that the best results were obtained with emulsions modified by button residue

Ensaios comparativos de mistura asfáltica pré-misturado a frio com adição de borracha de pneu

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Remediation of crude oil contaminated soils by means of bitumen emulsions

Effective remediation of contaminated sites with oils, heavy metals and other chemical agents is one of the most important environmental problems all over the world. Contaminated soils by petroleum from different sites and origins, might contaminate groundwater aquifers and then be spread by rain. Many years and the requirement of remedial techniques may be needed to remediate them. However, previous experiences show the uselessness of these methods for the solution of all problems. As any case of soil contamination is different, specific studies with relevant factors at financial aspects, legal limits and waste and soil characteristics are needed. In this work, a study of the use of bitumen asphalt emulsion to remediate contaminated soils by crude oils is exposed. By means of the soil stabilization technology, using the contaminated soils as aggregates and the tailor made emulsion as binder, the feasibility of the mix application to produce stable and resistant pavements is demonstrated

Surface rehabilitation techniques : state of the practice : design, construction, and performance of micro-surfacing /

"HNG-42/6-94(4M)E."

Stability of Granular Base Course Materials Containing Bituminous Admixtures

This report concerns the stabilization of three crushed limestones by an ss-1 asphalt emulsion and an asphalt cement, 120-150 penetration. Stabilization is evaluated by marshall stability and triaxial shear tests. Test specimens were compacted by the marshall, standard proctor and vibratory methods. Stabilization is evaluated primarily by triaxial shear tests in which confining pressures of 0 to 80 psi were used. Data were obtained on the angle of internal friction, cohesion, volume change, pore water pressure and strain characteristics of the treated and untreated aggregates. The MOHR envelope, bureau of reclamation and modified stress path methods were used to determine shear strength parameters at failure. Several significant conclusions developed by the authors are as follows: (1) the values for effective angle of internal friction and effective cohesion were substantially independent of asphalt content, (2) straight line MOHR envelopes of failure were observed for all treated stones, (3) bituminous admixtures did little to improve volume change (deformation due to load) characteristics of the three crushed limestones, (4) with respect to pore water characteristics (pore pressures and suctions due to lateral loading), bituminous treatment notably improved only the bedford stone, and (5) at low lateral pressures bituminous treatments increased stability by limiting axial strain. This would reduce rutting of highway bases. At high lateral pressures treated stone was less stable than untreated stone.

Asphalt Emulsions for Highway Construction (Emulsion Seal Coat), HR-1028, 1980

For the past several year Kossuth County has had a scheduled maintenance program of bituminous seal coating. This program has been used to maintain the 467 miles of asphaltic concrete surfaced roads in Kossuth County. Since most of the experience that Kossuth County had in seal coating was with cutback asphalt, it was decided to include the use of emulsified asphalt in Kossuth County's 1980 seal coat program. Federal Demonstration Project Funds were requested from the Federal Highway Administration to study the use of emulsified asphalt and funding was granted under Demonstration Project No. 55,:Asphalt Emulsions for Highway Construction." Items studied were design and construction procedure cost of alternate material, energy consumption and environmental considerations. A construction contract was awarded to Everds Brothers, Inc. of Algona, Iowa, on July 1, 1980. There were four bidders on the 54.5 miles of seal coating that was let. A map showing the location of the seal coating projects is shown in Appendix A, and a copy of the contract is shown in Appendix B. The contractor started the project on July 11, 1980 and completed the project on August 1, 1980. Construction inspection and follow-up inspections of the project were conducted by personnel of the Kossuth County Engineer's Office and testing of the materials, friction testing and road rater testing were conducted by the Material's Department of the Iowa Department of Transportation.