Properties of Sulfur Concrete

Ehsani, C. S. ""Evaluation of Physical "Properties of Sulfur-Concrete Blocks", MSCE thesis, Univ. Wash., Seattle, 1979. 

In examining the strength properties of sulfur concrete modified with styrene, the compressive strength was insufficient and worse than in the case of unmodified sulfur concrete (Table VI). After 70 days storage, however, the compressive strength of the test samples modified with 10 wt % styrene increased to 432 kp/cm2, which is an average of 46%. The increase in the test samples modified with 5 wt % styrene was 4%, corresponding to a value of 526 kp/cm2. 

T or many years scientists and engineers have attempted to modify the properties of sulfur so that it might be of value as a construction material, but until recently these random efforts lacked direction. Frequently the objectives of work described in many published papers could not be reconciled with the experimental design. For example, authors cited availability, low cost, and low toxicity as reasons for evaluating sulfur as a construction material. The same authors would then proceed to modify sulfur with additives which were in short supply, expensive, and highly toxic. The aging characteristics of sulfur concretes beyond a 28-day period were never examined, and durability outside the laboratory environment was seldom considered. With these limitations, the data were of little value to the construction industry. 

Finally some important properties of cement concrete, polymer concrete, and sulfur concrete are compared with each other. For the polymer concrete the data of a commercial polyester concrete were used. 

These early studies along with more recent investigations [31-34] established some conclusions regarding the effect of sulfur on the properties of SEA binders and the hot-mix concretes in which they were used. 

SUDICRETE, the trade name of a new material developed by the Sulphur Development Institute of Canada (SUDIC) possesses two important properties that are not found in other sulfur concretes ... 

In the melted state elementary sulfur is an excellent binder for aggregates such as sand, gravel, crushed stone, and similar materials. When a hot sulfur aggregate mixture is left to set, a material of concretelike hardness is obtained. This property leads to the term sulfur concrete or sulfur mortar, which is wrong strictly speaking, since the word concrete is used to refer to a product in which aggregates are bound with hydraulic products such as cement or with limestone. However, since polymer-bound aggregates recently developed to industrial maturity have been called polymer or synthetic resin concrete, the term sulfur concrete is maintained in this chapter. 

Table VIII. Comparison of the Important Properties of Cement, Polymer, and Sulfur Concretes...

It has been known for many years that sulfur can modify the properties of asphalts (38). With the recent dramatic increases in oil prices and hence the price of asphalt, the use of sulfur in flexible paving materials is being examined with renewed interest (39-45), particularly in areas where sulfur is available and is less expensive than asphalt. In addition to the possible economic benefits, if asphalt can be partially or completely replaced by sulfur in flexible pavement concretes, other benefits in terms of improved material properties might also accrue. 

A test program to determine the feasibility of direct substitution of sulfur for asphalt in preparing sulfur-asphalt concretes was conducted. Properties of the resultant materials were compared with those of emulsified sulfur-asphalt binder materials and conventional materials. In addition, a test program was conducted to determine if direct-substituted binders could be used to upgrade marginal aggregates for use in paving materials. 

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). 

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. 

Gies, A., and Knofel, D., "Influence of Sulfur on the Composition of Belite-Rich Cement Clinkers and the Technological Properties of the Resulting Cements," Cement and Concrete Research, Vol. 17,1987, pp. 317-328. 

Gies, A., and Kndfel, D. (1987) Influence of sulfur on the composition of belite-rich cement clinkers and technological properties of resulting cements. Cement and Concrete Research 17,317-328. 

It has been reported that the strength properties of concrete made with microsilica may be improved even further by a surface treatment of microsilica with sulfuric acid prior to mixing with other concrete mix components (Li and Chung, 1998). 

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