Sulfur field trials

Shell Canada Limited has been investigating the use of sulfur as a means of producing mixes with low quality aggregates since 1963. This work produced a series of patents [5-13] and experimental field trials [ 14., 15]. The results of these trials and an extensive research and development program [16-18] led to the development of a number of specialty items two of which are ... 

Figure 6. Heated dump body truck developed by Shell Canada, Ltd. used for hauling sand-asphalt-sulfur paving mixtures. [Photographed at the Kenedy County Texas field trials in 1977 (28)].

Sulfur-Extended-Asphalt Field Trials-MH 153, Brazos County,... 

Izatt, J. 0. "Sulfur-Extended-Asphalt Field Trials, M-153 Brazos County, Texas, A Detailed Construction Report" Report FHWA-TS-80-214, December 1979 ... 

Gallaway, . M. Saylak, D. "Sulfur Extended Asphalt (SEA) Sulphur/Asphalt Mixture Design and Construction Details - Lufkin Field Trials" Report FHWA-TS-78-203, January 1976 (reprint 1977). 

Early field trials were conducted in Saudi Arabia using this technology (22, 23). Considerable interest in sulfur asphalt pavements has been generated, but not projects of significance have been completed. Considerable research and development as well as demonstrations are continuing under the guidance of the Sulphur Development Institute of Canada. 

There is evidence that the Pronk additive reduces the evolution of sulfur vapors and gases. Air monitoring data are routinely collected during field trials. 

The emulsifying equipment has been set up as a self-contained trailer-mounted unit. The unit used at the 1975 field trial in Lufkin, Texas is designed to accept molten sulfur and hot asphalt from road tankers. The sulfur and asphalt flow rates are controlled by two proportioning pumps driven by a sprocket and chain arrangement from a common shaft. This arrangement enables the sulfur content of the binder to be varied from 20% to 50%. 

Sulfur-asphalt binders can be prepared by various mechanical means. One conventional method is to combine liquid sulfur and asphalt at 285°-300°F in a Gifford Wood colloid mill. A rotor stator gap setting of 0.02 in. at 7000 rpm for 8 min will prepare satisfactory emulsions. This emulsion is immediately mixed with preheated aggregate. The laboratory binder was prepared by TTI (Texas Transportation Institute) scientists in cooperation with SNPA (Societe Nationale des Petroles d Aquitaine) scientists and is believed to be comparable with the binders prepared by the turbine in the field trials. The need for dispersing sulfur in the asphalt is discussed by Garrigues (9) and by Kennepohl et al., Deme, and McBee et al. elsewhere in this volume. 

Various types of sulfur-asphalt pavement field test sections have been placed in the U.S., Canada, and Europe. Shell Canada Ltd. has conducted field trials in Canada (1,18,19,20). Gulf Oil Canada has also placed test sections of sulfur-asphalt pavement in which the sulfur and asphalt cement were incorporated into the mixture as an emulsion (4). Societe Nationale des Petroles D Aquitaine (SNPA) placed field test sections in France using the emulsion process (5). 

The U.S. Bureau of Mines participated in a field trial of sulfur-asphalt concrete pavement on U.S. Highway 93 near Boulder City, Nev. in January 1977. This test section is 2100 ft long. The aggregate-asphalt-sulfur (AAS) system was used to mix the ingredients. The sulfur and AC 40 asphalt cement were introduced into the pugmill as individual components. The sulfur comprised 27 w/o of the total binder. The aggregate used in the mixture was a crushed volcanic rock which conformed to the Asphalt Institute type IVb gradation. This test section is now in post-construction evaluation. 

The performance of the above pavements is being evaluated, and although the results are promising, a longer test period is necessary before conclusive results are obtained. A further field trial will be conducted at McLean, Saskatchwan during 1974. This trial will compare the performance of various sulfur-asphalt compositions and structures with conventional asphalt structures under low temperature conditions. The test road will include appropriate instrumentation. 

Mix Handling Trials. The general objective in conducting field trials was to use, with minimum modification, conventional asphalt equipment for processing, transporting, and placing sand-asphalt-sulfur mixes. To date, the mixes have been processed in batch-type hot-mix asphalt plants. Details of the processing steps were published in a previous report (4). In 1975, we intend to evaluate a continuous-type hot-mix... 

The idea of artificial fertilizers had long been known, but Liebig had placed this study on a firm scientific basis. Work in this field had been carried out by James Murray (1788 - 1881), who as early as 1817 had carried out field trials of bones dissolved in sulfuric acid. In 1842, his son John Fischer Murray filed a patent to manufacture a fertilizer fi-om calcium phosphate and sulfuric acid. 

Number of patents has been issued for MEOR. Zobell (1946) has described in his patent, use of the bacterium Desulfovibtio hydrocarbonoclasticus for MEOR method. In this study, he inoculated D. hydrocarbonoclasticus along with oxidized sulfur compounds and carbon source as lactose, but no field trials were performed. In his next patent, he introduced addition of oxygen free hydrogen produced by the action of a Clostridium species on a carbohydrate (Zobell, 1953). 

Paving Trials. A number of sand-asphalt-sulfur test pavements were constructed in Canada without rolling the mixes. The pavements were designed so that mix durability and field performance variables could be evaluated under actual in-service conditions. 

Sulfur mustard (SM) is unique among chemical warfare agents because of the large number of reports of its effects in man. The majority of these reports are of its effects after release on the battle field, and give a description of the types of effect and their time course from exposure to resolution of the injury. However, SM is also one of the few chemicals that have been the subject of tests on humans to determine how toxic they are in terms of the doses or dosages that produce toxic effects. Unlike reports of accidental or battlefield exposures, these trials were carried out in chambers under controlled, or at least carefully recorded, conditions, usually with analytical confirmation of chamber concentrations. Many of the reports of these trials, which were elassified at the time they were produced, have now been released into the public record and are available for scientific review. This chapter reviews those reports that are now available to the general public in addition to the work already published. Volunteer trials were carried out in the USA, UK, India and Australia. The reports of these trials that have been released to the public record are held by the Defense Technical Information Service... 

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