Sulfur concrete

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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]

Contents

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 allotropic (polymorphic) crystal phase at room temperature. With the addition of some modifying agents, elemental sulfur forms a copolymer (linear chains with styrene, cross-linking structure with DCPD [3] ) and remains plastic. [2] [lower-alpha 1]

Sulfur concrete then achieves high mechanical strength within ~ 24 hours of cooling. It does not require a prolonged curing period like conventional cement concrete, which after setting (a few hours) must still harden to reach its expected nominal strength at 28 days. The rate of hardening of sulfur concrete depends on its cooling rate and also on the nature and concentration of modifying agents (cross-linking process). [2] Its hardening is governed by the fairly rapid liquid/solid state change and associated phase transition processes (the added modifiers maintaining the plastic state while avoiding its recrystallization). It is a thermoplastic material whose physical state depends on temperature. It can be recycled and reshaped in a reversible way, simply by remelting it at high temperature.

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 impermeability, Loov et al. (1974) also consider amongst the beneficial characteristics of sulfur concrete its low thermal and electrical conductivities. Sulfur concrete does not cause adverse reaction with glass (no alkali–silica reaction), does not produce efflorescences, and also presents a smooth surface finish. They also mention amongst its main limitations, its high coefficient of thermal expansion, the possible formation of acid under the action of water and sunlight. It also reacts with copper and produces a smell when melted.

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,[ when? ] it has been proposed as a near-carbon-neutral construction material. Its waterless and less energy-intensive production (in comparison with ordinary cement and regular concrete) makes it a potential alternative for high- CO
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] THIOTUBE is the brand name for certified acid-resistant DWF (dry weather flow) discharge pipes used in Belgium.

Long-term scientific and technical challenges

Sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) produce hydrogen sulfide (H2S) and sulfuric acid (H2SO4) respectively. When the sulfur cycle is active in sewers and H2S emanations from the effluent waters are oxidized in H2SO4 by atmospheric oxygen at the moist surface of tunnel walls, sulfuric acid can attack the hydrated Portland cement paste of cementitious materials, especially in the non-totally immersed sections of sewers (non-completely water-filled vadose zone). [13] It causes extensive damages to masonry mortar and concrete in older sewage infrastructures. [14] [15] Sulfur concrete, if proven resistant to long-term chemical and bacterial attacks, could provide an effective and long-lasting solution to this problem. However, since elemental sulfur itself participates in redox reactions used by some autotrophic bacteria to produce the energy they need from the sulfur cycle, elemental sulfur could contribute directly fueling the bacterial activity. [16] Biofilms adhering to the surface of sewer walls could harbor autotrophic microbial colonies that can degrade sulfur concrete if they are able to use elemental sulfur directly as an electron donor to reduce nitrate (autotrophic denitrification process), [17] [18] [19] [20] or sulfate, present in wastewater. Studies and real life tests have shown that only bio sulfur is accessible to these bacteria.

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
2
SO
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
2
S
/H
2
SO
4
= 3/1. Hydrogen sulfide (H
2
S
) causes sulfide stress cracking (SSC) and in contact with air is also easily oxidized into thiosulfate ( S
2
O2−
3
), responsible for pitting corrosion.

Like pyrite ( FeS
2
, iron(II) disulfide), in the presence of moisture, sulfur is also sensitive to oxidation by atmospheric oxygen and could ultimately produce sulfuric acid ( H
2
SO
4
), sulfate ( SO2−
4
), and intermediate chemical species such as thiosulfates ( S
2
O2−
3
), or tetrathionates ( S
4
O2−
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...) 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 ( CaCO
3
) and concrete structures while also producing expansive gypsum ( CaSO
4
·2H
2
O
), 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 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 ( Ca(OH)
2
), 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.

See also

Notes

  1. In the natural rubber vulcanization process developed by Charles Goodyear, elemental sulfur is added to the material (extracted from rubber tree latex) heated to high temperatures to cross-link it (cross-linking with formation of 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 plasticity during its cooling/hardening. In both cases, cross-linking reactions take place between the sulfur and the organic molecules.

Related Research Articles

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Sulfur (also spelled sulphur in British English) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature.

The term chloride refers to a compound or molecule that contains either a chlorine ion, which is a negatively charged chlorine atom, or a non-charged chlorine atom covalently bonded to the rest of the molecule by a single bond. Many inorganic chlorides are salts. Many organic compounds are chlorides. The pronunciation of the word "chloride" is.

<span class="mw-page-title-main">Corrosion</span> Gradual destruction of materials by chemical reaction with its environment

Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials by chemical or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion.

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<i>Acidithiobacillus</i> Genus of bacteria

Acidithiobacillus is a genus of the Acidithiobacillia in the phylum "Pseudomonadota". This genus includes ten species of acidophilic microorganisms capable of sulfur and/or iron oxidation: Acidithiobacillus albertensis, Acidithiobacillus caldus, Acidithiobacillus cuprithermicus, Acidithiobacillus ferrianus, Acidithiobacillus ferridurans, Acidithiobacillus ferriphilus, Acidithiobacillus ferrivorans, Acidithiobacillus ferrooxidans, Acidithiobacillus sulfuriphilus, and Acidithiobacillus thiooxidans.A. ferooxidans is the most widely studied of the genus, but A. caldus and A. thiooxidans are also significant in research. Like all "Pseudomonadota", Acidithiobacillus spp. are Gram-negative and non-spore forming. They also play a significant role in the generation of acid mine drainage; a major global environmental challenge within the mining industry. Some species of Acidithiobacillus are utilized in bioleaching and biomining. A portion of the genes that support the survival of these bacteria in acidic environments are presumed to have been obtained by horizontal gene transfer.

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<span class="mw-page-title-main">Microbiologically induced calcite precipitation</span> Bio-geochemical process

Microbiologically induced calcium carbonate precipitation (MICP) is a bio-geochemical process that induces calcium carbonate precipitation within the soil matrix. Biomineralization in the form of calcium carbonate precipitation can be traced back to the Precambrian period. Calcium carbonate can be precipitated in three polymorphic forms, which in the order of their usual stabilities are calcite, aragonite and vaterite. The main groups of microorganisms that can induce the carbonate precipitation are photosynthetic microorganisms such as cyanobacteria and microalgae; sulfate-reducing bacteria; and some species of microorganisms involved in nitrogen cycle. Several mechanisms have been identified by which bacteria can induce the calcium carbonate precipitation, including urea hydrolysis, denitrification, sulfate production, and iron reduction. Two different pathways, or autotrophic and heterotrophic pathways, through which calcium carbonate is produced have been identified. There are three autotrophic pathways, which all result in depletion of carbon dioxide and favouring calcium carbonate precipitation. In heterotrophic pathway, two metabolic cycles can be involved: the nitrogen cycle and the sulfur cycle. Several applications of this process have been proposed, such as remediation of cracks and corrosion prevention in concrete, biogrout, sequestration of radionuclides and heavy metals.

<i>Acidithiobacillus thiooxidans</i> Species of bacterium

Acidithiobacillus thiooxidans, formerly known as Thiobacillus thiooxidans until its reclassification into the newly designated genus Acidithiobacillus of the Acidithiobacillia subclass of Pseudomonadota, is a Gram-negative, rod-shaped bacterium that uses sulfur as its primary energy source. It is mesophilic, with a temperature optimum of 28 °C. This bacterium is commonly found in soil, sewer pipes, and cave biofilms called snottites. A. thiooxidans is used in the mining technique known as bioleaching, where metals are extracted from their ores through the action of microbes.

<span class="mw-page-title-main">Flowers of sulfur</span> Very fine, bright yellow sulfur powder that is produced by sublimation and deposition

Flowers of sulfur is a very fine, bright yellow sulfur powder that is produced by sublimation and deposition. It can contain up to 30% of the amorphous allotrope of sulfur, which is the noncrystalline structure of sulfur. It is known as flores sulphuris by apothecaries and in older scientific works. Natural sulfur was also known as brimstone, hence the alternative name flowers of brimstone.

The genus Annwoodia was named in 2017 to circumscribe an organism previously described as a member of the genus Thiobacillus, Thiobacillus aquaesulis - the type and only species is Annwoodia aquaesulis, which was isolated from the geothermal waters of the Roman Baths in the city of Bath in the United Kingdom by Ann P. Wood and Donovan P. Kelly of the University of Warwick - the genus was subsequently named to honour Wood's contribution to microbiology. The genus falls within the family Thiobacillaceae along with Thiobacillus and Sulfuritortus, both of which comprise autotrophic organisms dependent on thiosulfate, other sulfur oxyanions and sulfide as electron donors for chemolithoheterotrophic growth. Whilst Annwoodia spp. and Sulfuritortus spp. are thermophilic, Thiobacillus spp. are mesophilic.

<span class="mw-page-title-main">Microbial oxidation of sulfur</span>

Microbial oxidation of sulfur is the oxidation of sulfur by microorganisms to build their structural components. The oxidation of inorganic compounds is the strategy primarily used by chemolithotrophic microorganisms to obtain energy to survive, grow and reproduce. Some inorganic forms of reduced sulfur, mainly sulfide (H2S/HS) and elemental sulfur (S0), can be oxidized by chemolithotrophic sulfur-oxidizing prokaryotes, usually coupled to the reduction of oxygen (O2) or nitrate (NO3). Anaerobic sulfur oxidizers include photolithoautotrophs that obtain their energy from sunlight, hydrogen from sulfide, and carbon from carbon dioxide (CO2).

References

  1. Abdel-Mohsen Onsy Mohamed; Maisa El-Gamal (15 July 2010). Sulfur Concrete for the Construction Industry: A Sustainable Development Approach. J. Ross Publishing. p. 109. ISBN   978-1-60427-005-1.
  2. 1 2 3 Lewandowski, Michał; Kotynia, Renata (2018). "Assessment of sulfur concrete properties for use in civil engineering". MATEC Web of Conferences. 219: 03006. doi: 10.1051/matecconf/201821903006 .
  3. Bordoloi, Binoy K.; Pearce, Eli M. (1 March 1978). "Plastic sulfur stabilization by copolymerization of sulfur with dicyclopentadiene". In: New uses of sulfur — II. Advances in Chemistry. Vol. 165. American Chemical Society. pp. 31–53. doi:10.1021/ba-1978-0165.ch003. ISBN   9780841203914. ISSN   0065-2393.
  4. McKay, G., U.S. Patent No. 643, February 13, 1900, p. 251.
  5. 1 2 3 Loov, Robert E.; Vroom, Alan H.; Ward, Michael A. (1974). "Sulfur concrete – A new construction material" (PDF). PCI Journal. 19 (1). Prestressed Concrete Institute: 86–95. doi: 10.15554/pcij.01011974.86.95 . 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)
  6. Bourne, Douglas J., ed. (1978). "A New Approach to Sulfur Concrete". New uses of sulfur — II. Advances in Chemistry. Vol. 165. Washington, D.C.: American Chemical Society. pp. 54–78. doi:10.1021/ba-1978-0165.ch004. ISBN   978-0-8412-0391-4.
  7. Gregor, R.; Hackl, A. (March 1, 1978). "Chapter 4: A new approach to sulfur concrete". In Bourne, Douglas J. (ed.). New uses of sulfur — II. Advances in Chemistry. Vol. 165. Washington, D.C.: American Chemical Society. pp. 54–78. doi:10.1021/ba-1978-0165.ch004. ISBN   978-0-8412-0391-4.{{cite book}}: CS1 maint: date and year (link)
  8. Brandt, Andrzej Marek (1995). Cement-based composites: Materials, mechanical properties and performance. CRC Press. p. 52. ISBN   978-0-419-19110-0.
  9. 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.
  10. "To build settlements on Mars, we'll need materials chemistry". cen.acs.org. 2017-12-27. Retrieved 2022-04-14.
  11. 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
  12. Infrabel (8 March 2021). "First recyclable sulfur concrete sleepers placed in Belgium". RailTech.com. Retrieved 14 April 2022.
  13. Satoh, Hisashi; Odagiri, Mitsunori; Ito, Tsukasa; Okabe, Satoshi (2009). "Microbial community structures and in situ sulfate-reducing and sulfur-oxidizing activities in biofilms developed on mortar specimens in a corroded sewer system". Water Research. 43 (18): 4729–4739. Bibcode:2009WatRe..43.4729S. doi:10.1016/j.watres.2009.07.035. hdl: 2115/45290 . PMID   19709714. S2CID   10227999.
  14. Scrivener, Karen; De Belie, Nele (2013), Alexander, Mark; Bertron, Alexandra; De Belie, Nele (eds.), "Bacteriogenic Sulfuric Acid Attack of Cementitious Materials in Sewage Systems", Performance of Cement-Based Materials in Aggressive Aqueous Environments, RILEM State-of-the-Art Reports, vol. 10, Dordrecht: Springer Netherlands, pp. 305–318, doi:10.1007/978-94-007-5413-3_12, ISBN   978-94-007-5412-6 , retrieved 2022-10-02
  15. Alexander, Mark G.; Bertron, Alexandra; Nele, De Belie (2013). Performance of cement-based materials in aggressive aqueous environments. Dordrecht: Springer. ISBN   978-94-007-5413-3. OCLC   823643788.{{cite book}}: |work= ignored (help)CS1 maint: date and year (link)
  16. Okabe, Satoshi; Ito, Tsukasa; Sugita, Kenichi; Satoh, Hisashi (2005). "Succession of internal sulfur cycles and sulfur-oxidizing bacterial communities in microaerophilic wastewater biofilms". Applied and Environmental Microbiology. 71 (5): 2520–2529. Bibcode:2005ApEnM..71.2520O. doi:10.1128/AEM.71.5.2520-2529.2005. ISSN   0099-2240. PMC   1087539 . PMID   15870342. Okabe_2005.
  17. Batchelor, B (1978). "A kinetic model for autotrophic denitrification using elemental sulfur". Water Research. 12 (12): 1075–1084. Bibcode:1978WatRe..12.1075B. doi:10.1016/0043-1354(78)90053-2. Batchelor_1978.
  18. Claus, Günter; Kutzner, Hans Jürgen (1985). "Autotrophic denitrification by Thiobacillus denitrificans in a packed bed reactor". Applied Microbiology and Biotechnology. 22 (4). doi:10.1007/BF00252032. ISSN   0175-7598. S2CID   23359931.
  19. Koenig, A.; Liu, L. H. (1996). "Autotrophic denitrification of landfill leachate using elemental sulphur". Water Science and Technology. 34 (5–6): 469–476. doi:10.2166/wst.1996.0584. ISSN   0273-1223.
  20. Lee, Chang Soo; Kim, Kwang Kyu; Aslam, Zubair; Lee, Sung-Taik (2007). "Rhodanobacter thiooxydans sp. nov., isolated from a biofilm on sulfur particles used in an autotrophic denitrification process". International Journal of Systematic and Evolutionary Microbiology. 57 (8): 1775–1779. doi: 10.1099/ijs.0.65086-0 . ISSN   1466-5026. PMID   17684255.
  21. 1 2 3 Swamy, R. N.; Jurjees, T. A. R. (1986-09-01). "Stability of sulphur concrete beams with steel reinforcement". Materials and Structures. 19 (5): 351–360. doi:10.1007/BF02472125. ISSN   1871-6873. S2CID   135888809 . Retrieved 2023-03-25.
  22. 1 2 MacDonald, Digby D.; Roberts, Bruce; Hyne, James B. (1978). "The corrosion of carbon steel by wet elemental sulphur". Corrosion Science. 18 (5): 411–425. doi:10.1016/S0010-938X(78)80037-7. ISSN   0010-938X . Retrieved 2022-09-19.
  23. 1 2 Maldonado-Zagal, S. B.; Boden, P. J. (1982). "Hydrolysis of elemental sulphur in water and its effect on the corrosion of mild steel". British Corrosion Journal. 17 (3): 116–120. doi:10.1179/000705982798274336. ISSN   0007-0599 . Retrieved 2022-09-19.
  24. Smith, Liane; Craig, Bruce D. (2005-04-03). Practical corrosion control measures for elemental sulfur containing environments. Corrosion 2005. OnePetro. Retrieved 2022-09-19.
  25. Fang, Haitao; Young, David; Nesic, Srdjan (2008). Corrosion of mild steel in the presence of elemental sulfur. Corrosion 2008. OnePetro.
  26. Fang, Haitao; Brown, Bruce; Young, David; Nešic, Srdjan (2011-03-13). Investigation of elemental sulfur corrosion mechanisms. Corrosion 2011. OnePetro. Retrieved 2022-09-19.
  27. Little, B.J.; Ray, R.I.; Pope, R.K. (2000-04-01). "Relationship between corrosion and the biological sulfur cycle: A review". Corrosion. 56 (4): 433–443. doi:10.5006/1.3280548. ISSN   0010-9312.

Further reading