Concrete, sulfur applications

The inclusion of other aggregates which have been tested and added for various road systems includes sulfur, shredded discarded tires, limestone (<200 mesh), and crushed concrete. Other applications of bitumen are in roofing, flooring, and as an anticorrosion coating on surfaces exposed to corrosive atmosphere, aggressive soils, and chemicals. The main advantage of bitumen, in many of its applications, is that it is cheaper than alternative materials. The world production of bitumen in 1993 was about 17 Mt. 

Sulfur Impregnation (14). Stronger and more durable products such as Portland cement concrete, ceramic tile and even wood and paper products have been shown to be feasible. In addition, sulfur as an impregnant for fabric liner systems would have application in ponds, holding tanks, etc. 

Sulfur Coatings (1J>, 18). Molten sulfur, often mixed with fibers or modifiers can be used to spray coatings on unbonded block or brick buildings, linings for ponds, portland cement concrete, and other applications where a durable coating is required or useful. 

The improved performance of SC over PCC is of importance not only in the applications such as corrosive industrial situations, but also in certain regular construction applications. In some areas of the world, the mineral aggregates available locally do not produce a PCC capable of withstanding the climate conditions. However, those aggregates may be used in SC to give durable building materials. Examples of this aspect of the use of sulfur concretes are sulfur concrete block projects developed by Ortega... 

A wide range of applications for sulfur concrete such as SUDICRETE provide many advantages. Included are industrial flooring, electrolytic vats, sumps, catch basins, tanks, sewage and waste impoundment ponds, bridge decks, pipes, etc., all of which can benefit from its extreme corrosion resistance. Rapid... 

The process of infusing concrete with molten sulfur was recorded as early as 1924, when Kobbe (10) attempted to produce a strong, water-resistant material. The simple immersion method he used is effective if sufficient time is permitted to infiltrate precast units in controlled environments (II). However, mass production and field applications may demand that the procedure be accelerated, for example, by using modi-... 

Sulfur composite was evaluated for this use because less site preparation was required than for concrete linings, the application equipment was mobile, and the composite could be applied potentially in the winter months when the canals were not in service. Concrete canal lining work is normally halted when the temperature drops below freezing. 

Concrete Coatings. The durability, weatherability, and chemical resistance of composites match up well with the required properties of protective coatings for concrete and other rigid materials. A typical application is the protection of concrete structures from the acid solutions used in metal ore leaching plants (9). In one such application, sulfur composite was applied to two leaching vats of a new experimental copper ore leaching facility (Figure 8). 

These results demonstrate the high level of protection that sulfur composites can provide to concrete and to other rigid materials. Examples of other possible applications are sewage treatment tanks and ponds, marine structures, pipe, and masonry block structures. 

Construction applications for sulfur have also been tested. Interlocking bricks made predominantly of sulfur have been found to speed up construction, but have inherent fire hazards, which restrict their use. Concrete blocks impregnated with molten sulfur have shown a more than tenfold increase in compressive strength, from 5.9 to 83.9 MPa (megapascals 1 MPa = 10 N/m ), at the same time as an improvement in tensile strength from 1.3 MPa to 8.5 MPa, for a 13-15% sulfur content [7]. It also improves its chemical resistance. Sulfur-coated bamboo has been found to be an economical yet effective concrete reinforcing agent as a replacement for steel, in areas where bamboo occurs naturally. 

High Bearing Capacity Mixes. Conventional asphalt concrete mixes often deform under high loads over long loading periods. Thus conventional asphalt concrete is unsuitable for applications such as heavy duty industrial floors and container ports. The creep properties of such mixes may be improved considerably by adding sulfur to the mix. 

Base Layer Gravels (0/25). The binders have a pen. 40/50 asphalt base, with the sulfur/asphalt ratio of 30/70 by weight. The formulations studied corresponded to a bituminous, semi-crushed type, concrete for base layer applications for a traffic load of 3 tons. The crushed material in these formulae was replaced by round material, and the filler was... 

The sulfur based marking paints have shown outstanding wear characteristics on asphalt and concrete pavements 54), They performed better than standard paints in all climates and weather when tested in residential communities, rural areas, and in parking lots, as well as on busy highways and in major metropolitan areas. Some of the advantages of sulfur paints are summarized in Table V. Relatively sophisticated application equipment which automatically dispenses reflecting beads was developed and tested in North America and Europe. 

Hydrated supersulfated cement is highly resistant to snlfate attack, and may be used in applications in which the concrete is exposed to highly concentrated sulfate solutions. TTie high sulfate resistance is dne to the fact that most or all of the AI2O3 (except that in the residual, non-reacted slag) is present in the form of ettringite, or is bound within the formed C-S-H phase, and is not available for a reaction with sulfate ions. Such sulfate resistance is limited to alkah and calcium sulfate solutions, or to moderately acid solutions (down to abont pH=3.5), in which the sulfate ions are present in the form of ammoninm sulfate or even as free sulfuric add of low concentrations. 

Because of its flammability and the potential for oxides of sulfur, it is not normally used for most indoor applications. Table 10.2 provides the resistance of sulfur concrete to atmospheric corrosion. 

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