text: Swamy and Jurjees (1986) have pointed out the limitations of sulfur concrete. They questioned the stability and the long-term durability of sulfur concrete beams with steel reinforcement, especially for sulfur concrete modified with dicyclopentadiene and dipentene. Even when dry, modified concrete beams show strength loss with ageing. Ageing in a wet environment leads to softening of sulfur concrete and loss of strength. It causes structural damages in sulfur concrete beams leading to shear failures and cracking. Swamy and Jurjees (1986) also observed severe corrosion of steel reinforcements. They concluded that the stability of reinforced sulfur concrete beams can only be guaranteed when they are unmodified and kept dry.
  Being based on the use of elemental sulfur (S, or S) as a binder, sulfur concrete applications are expected to suffer the same limitations as those of elemental sulfur which is not a really inert material, can burn, and is also known to be a potent corrosive agent. 
  In case of fire, this concrete is flammable and will generate toxic and corrosive fumes of sulfur dioxide (), and  sulfur trioxide (), ultimately leading to the formation of sulfuric acid (). 
  According to Maldonado-Zagal and Boden (1982), the hydrolysis of elemental sulfur (octa-atomic sulphur, S) in water is driven by its disproportionation into oxidised and reduced forms in the ratio / = 3/1. Hydrogen sulfide () causes sulfide stress cracking (SSC) and in contact with air is also easily oxidized into thiosulfate (), responsible for pitting corrosion. 
  Like pyrite (, iron(II) disulfide), in the presence of moisture, sulfur is also sensitive to oxidation by atmospheric oxygen and could ultimately produce sulfuric acid (), sulfate (), and intermediate chemical species such as thiosulfates (), or tetrathionates (),  which are also strongly corrosive substances (pitting corrosion), as all the reduced species of sulfur. Therefore, long-term corrosion problems of steels and other metals (aluminium, copper...) need to be anticipated, and correctly addressed, before selecting sulfur concrete for specific applications.
  The formation of sulfuric acid could also attack and dissolve limestone () and concrete structures while also producing expansive gypsum (), aggravating the formation of cracks and fissures in these materials.
  If the local physico-chemical conditions are conducive (sufficient space and water available for their growth), sulfur-oxidizing bacteria (microbial oxidation of sulfur) could also thrive at the expense of concrete sulfur and contribute to aggravate potential corrosion problems.
  The degradation rate of elemental sulfur depends on its specific surface area. The degradation reactions are the fastest with sulfur dust, or crushed powder of sulfur, while intact compact blocks of sulfur concrete are expected to react more slowly. The service life of components made of sulfur concrete depends thus on the degradation kinetics of elemental sulfur exposed to atmospheric oxygen, moisture and microorganisms, on the density/concentration of microcracks in the material, and on the accessibility of the carbon-steel surface to the corrosive degradation products present in aqueous solution in case of macrocracks or technical voids exposed to water ingress. All these factors need to be taken into account when designing structures, systems and components (SSC) based on sulfur concrete, certainly if they are reinforced, or pre-stressed, with steel elements (rebar or tensioning cables respectively).
  While the process of elemental sulfur oxidation will also lower the pH value, aggravating carbon steel corrosion, in contrast to ordinary Portland cement and classical concrete, fresh sulfur concrete does not contain alkali hydroxides (KOH, NaOH), nor calcium hydroxide (), and therefore does not provide any buffering capacity to maintain a high pH passivating the steel surface. In other words, intact sulfur concrete does not chemically protect steel reinforcement bars (rebar) against corrosion. The corrosion of steel elements embedded into sulfur concrete will thus depends on water ingress through cracks and to their exposure to aggressive chemical species of sulfur dissolved in the seeping water. The presence of microorganisms fuelled by elemental sulfur could also play a role and accelerate the corrosion rate.