Sulfur concrete
Sulfur concrete, sometimes named thioconcrete or sulfurcrete, is a composite construction material, composed mainly of sulfur and aggregate (generally a coarse aggregate made of gravel or crushed rocks and a fine aggregate such as sand). Cement and water, important compounds in normal concrete, are not part of sulfur concrete. The concrete is heated above the melting point of elemental sulfur (115.21 °C (239.38 °F)) at ca. 140 °C (284 °F) in a ratio of between 12% and 25% sulfur, the rest being aggregate.[1]
Low-volatility (i.e., with a high boiling point) organic admixtures (sulfur modifiers), such as dicyclopentadiene (DCPD), styrene, turpentine, or furfural, are also added to the molten sulfur to inhibit its crystallization and to stabilize its polymeric structure after solidification.[2]
In the absence of modifying agents, elemental sulfur crystallizes in its most stable
Sulfur concrete then achieves high
A sulfur concrete patent was already registered in 1900 by McKay.[4][5] Sulfur concrete was studied in the 1920s and 1930s and received renewed interest in the 1970s because of the accumulation of large quantities of sulfur as a by-product of the hydrodesulfurization process of oil and gas production and its low cost.[5][6][7]
Characteristics
Sulfur concrete has a low porosity and is a poorly permeable material. Its low hydraulic conductivity slows down water ingress in its low porosity matrix and so decreases the transport of harmful chemical species, such as chloride (pitting corrosion), towards the steel reinforcements (physical protection of steel as long as no microcracks develop in the sulfur concrete matrix). It is resistant to some compounds like acids which attack normal concrete.
Beside its
Uses
Sulfur concrete was developed and promoted as a building material to get rid of large amounts of stored sulfur produced by hydrodesulfurization of gas and oil (Claus process). As of 2011, sulfur concrete has only been used in small quantities when fast curing or acid resistance is necessary.[8][5]The material has been suggested by researchers as a potential building material on Mars, where water and limestone are not easily available, but sulfur is.[9][10][11]
Advantages and benefits
More recently,[
2-emission portland-cement-based materials. Due to improvements in fabrication techniques, it can be produced in high quality and large quantities.[citation needed] Recyclable sulfur concrete sleepers are used in Belgium for the railways infrastructure, and are mass-produced locally.[12]
Long-term scientific and technical challenges
The very long-term durability of sulfur concrete also depends on physicochemical factors such as those controlling, among other things, the diffusion of modifying agents (if not completely chemically fixed) out of the elemental sulfur matrix and their leaching by water. The resulting changes in the physical properties of the material will determine its long-term mechanical strength and chemical behavior. The biodegradability of the organic admixtures (sulfur modifiers), or their resistance to microbial activity, and their possible biocidal properties (which may protect the sulfur concrete from microbial attack) are important aspects in assessing the durability of the material. This could also depend on the progressive recrystallization of elemental sulfur over time, or on the rate of plastic deformation of its structure modified by the different types of organic admixtures.
Disadvantages and limitations
Swamy and Jurjees (1986) have pointed out the limitations of sulfur concrete.[21] 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.[21] They concluded that the stability of reinforced sulfur concrete beams can only be guaranteed when they are unmodified and kept dry.[21]
Being based on the use of elemental sulfur (S0, or S8) 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.[22][23][24]
In case of fire, this concrete is flammable and will generate toxic and corrosive fumes of sulfur dioxide (SO
2), and sulfur trioxide (SO
3), ultimately leading to the formation of sulfuric acid (H
2SO
4).
According to Maldonado-Zagal and Boden (1982),[23] the hydrolysis of elemental sulfur (octa-atomic sulphur, S8) in water is driven by its disproportionation into oxidised and reduced forms in the ratio H
2S/H
2SO
4 = 3/1. Hydrogen sulfide (H
2S) causes sulfide stress cracking (SSC) and in contact with air is also easily oxidized into thiosulfate (S
2O2−
3), responsible for pitting corrosion.
Like
2SO
4), sulfate (SO2−
4), and intermediate chemical species such as thiosulfates (S
2O2−
3), or tetrathionates (S
4O2−
6), which are also strongly corrosive substances (pitting corrosion), as all the reduced species of sulfur.[22][25][26] Therefore, long-term corrosion problems of steels and other metals (aluminium, copper
The formation of sulfuric acid could also attack and dissolve limestone (CaCO
3) and concrete structures while also producing expansive gypsum (CaSO
4·2H
2O), 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.[27]
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
See also
- Asphalt concrete, similar aggregate material using 'bitumen' as a binder
- Sulfur-based lunarcrete, a proposed lunar construction material
- Cenocell, a concrete material using fly ash cenospheres (hollow spheres) in place of cement
- Rubber disulfide bridges formed after the reaction of elemental sulfur with natural rubber terpenoids (polyisoprene) (process discovered by Charles Goodyear)
- ) heated at elevated temperature
Notes
- disulfide bonds). In sulfur concrete, the opposite is true: a low-volatility organic liquid (dicyclopentadiene (DCPD), styrene, turpentine, or furfural...) is added to the molten sulfur to inhibit its crystallization and maintain a certain plasticityduring its cooling/hardening. In both cases, cross-linking reactions take place between the sulfur and the organic molecules.
References
- ISBN 978-1-60427-005-1.
- ^ .
- ISSN 0065-2393.
- ^ McKay, G., U.S. Patent No. 643, February 13, 1900, p. 251.
- ^ ISSN 0887-9672. Archived from the original on 2012-03-22. Retrieved 2022-09-20.)
{{cite journal}}
: CS1 maint: bot: original URL status unknown (link - ISBN 978-0-8412-0391-4.
- ISBN 978-0-8412-0391-4.)
{{cite book}}
: CS1 maint: date and year (link - ISBN 978-0-419-19110-0.
- ^ Wan, Lin, Roman Wendner, and Gianluca Cusatis (2016). "A novel material for in situ construction on Mars: experiments and numerical simulations." Construction and Building Materials, 120: 222–231.
- ^ "To build settlements on Mars, we'll need materials chemistry". cen.acs.org. 2017-12-27. Retrieved 2022-04-14.
- ^ Nick Jones (2019). "Mixing it on Mars" (PDF). sustainableconcrete.org.uk. The Concrete Centre. pp. 18–19. Retrieved 19 September 2022.
Marscrete will be mission-critical to any future landing on the Red Planet, writes Nick Jones
- ^ Infrabel (8 March 2021). "First recyclable sulfur concrete sleepers placed in Belgium". RailTech.com. Retrieved 14 April 2022.
- S2CID 10227999.
- ISBN 978-94-007-5412-6, retrieved 2022-10-02
- )
- PMID 15870342. Okabe_2005.
- . Batchelor_1978.
- S2CID 23359931.
- ISSN 0273-1223.
- PMID 17684255.
- ^ S2CID 135888809. Retrieved 2023-03-25.
- ^ ISSN 0010-938X. Retrieved 2022-09-19.
- ^ ISSN 0007-0599. Retrieved 2022-09-19.
- ^ Smith, Liane; Craig, Bruce D. (2005-04-03). Practical corrosion control measures for elemental sulfur containing environments. Corrosion 2005. OnePetro. Retrieved 2022-09-19.
- ^ Fang, Haitao; Young, David; Nesic, Srdjan (2008). Corrosion of mild steel in the presence of elemental sulfur. Corrosion 2008. OnePetro.
- ^ Fang, Haitao; Brown, Bruce; Young, David; Nešic, Srdjan (2011-03-13). Investigation of elemental sulfur corrosion mechanisms. Corrosion 2011. OnePetro. Retrieved 2022-09-19.
- ISSN 0010-9312.
Further reading
- Husam A. Omar & Mohsen Issa (1994). "Production of Lunar Concrete Using Molten Sulfur" (PDF). In Rodney G. Galloway & Stanley Lokaj (eds.). Engineering, construction, and operations in space IV: Space '94; Proceedings of the 4th International Conference, Albuquerque, New Mexico, February 26–March 3, 1994. Vol. 2. New York: ISBN 0872629376.
- I. Casanova (1997). "Feasibility and Applications of Sulfur Concrete for Lunar Base Development: A Preliminary Study" (PDF). 28th Annual Lunar and Planetary Science Conference, March 17–21, 1997, Houston, TX. p. 209.
- T. D. Lin; Steven B. Skaar & Joseph J. O'Gallagher (April 1997). "Proposed remote control solar powered concrete production experiment on the Moon". Aerospace Engineering. 10 (2): 104–109. .
- Houssam Toutanji; Becca Glenn-Loper & Beth Schrayshuen (2005). "43rd AIAA Aerospace Sciences Meeting and Exhibit". 43rd AIAA Aerospace Sciences Meeting and Exhibit 10 – 13 January 2005, Reno, Nevada. American Institute of Aeronautics and Astronautics. ISBN 978-1-62410-064-2.
- R.N. Grugel & Houssam Toutanji (2006). "Viability of Sulfur "Concrete" on the Moon: Environmental Consideration". Proceedings: 43rd American Institute of Aeronautics and Astronautics (AIAA), Reno, NV, Jan. 9-12, 2006. — also:
- R. Grugel & Houssam Toutanji (2006). "Viability of Sulfur Concrete on the Moon: Environmental Considerations". Journal of Advances in Space Research.
- Richard N. Grugela & Houssam Toutanji (2008). "Sulfur "concrete" for lunar applications — Sublimation concerns". Advances in Space Research. 41 (1): 103–112. .
- Dugarte, Margareth; Martinez-Arguelles, Gilberto; Torres, Jaime (2019). "Experimental evaluation of modified sulfur concrete for achieving sustainability in industry applications". Sustainability. 11 (1): 70. ISSN 2071-1050.
External links
- Infrabel (8 March 2021). "First recyclable sulfur concrete sleepers placed in Belgium". RailTech.com. Retrieved 14 April 2022.