Asbestos Use in Bricks or Mortar

Do some bricks or mortar contain asbestos?

Research on Asbestos Use in Brick Products - Or Not

• ASBESTOS HISTORY & PROPERTIES [Book online] D.V. Rosato, engineering consultant, Newton MA, Reinhold Publishing Co., NY, 1959, Library of Congress Catalog No. 59-12535. We have re-published this text as an online book at InspectApedia.
  
  Excerpts & adaptations are also found in InspectApedia.com articles on asbestos history, production & visual identification in and on buildings.

Above: Pyro Products Fire Brick advertised in Building Supply News in 1925. Note that this advertisement does not mention use of asbestos.

• Asbestos ceramic bricks:
  
  Leonelli et als. refer to the disposition of asbestos by microwave treatment of asbestos waste into ceramic bricks - another possible source of association of the words "ceramic" and "asbestos" in web searches that does not extend to ceramic tiles. National Center for Biotechnology Information, NIH, USA[24]
• Asbestos in clay products - sources:
  
  Asbestos has been reported in art clay (such as Fibro-Clay)[37] used in schools and in pottery clay where it occurred in the form of talc added as a flux to lower the firing temperature.
  
  Talc and clay from at least one U.S. mine contained anthophyllite asbestos. It was unclear whether or not this material fell under the aegis of asbestos regulation.[36] The asbestos content of talc depended on where it was mined, and some talcs were asbestos-free[40].
  
  Depending on the quarry source there may be deliberate or accidental inclusion of asbestos in terra cotta tiles such as roofing tiles.
  
  Other clay products that may have had asbestos added in the form of talc or vermiculite (some vermiculite contains asbestos) in addition to art clays, may include clays used as pipe joint seals or insulation, and in the production of firebricks used to line the combustion chambers of heating equipment such as boilers or furnaces, and other school art projects such as paper maches.[38][39]
• [24] Microwave thermal inertisation of asbestos containing waste and its recycling in traditional ceramics. Leonelli C, Veronesi P, Boccaccini DN, Rivasi MR, Barbieri L, Andreola F, Lancellotti I, Rabitti D, Pellacani GC. Dipartimento di Ingegneria dei Materiali e dell'Ambiente, Università di Modena e Reggio Emilia, Via Vignolese 905, 41100 Modena, Italy. leonelli@unimore.it Journal of Hazardous Materials 135 (1–3): 149–155 - Citation: J Hazard Mater. 2006 Jul 31;135(1-3):149-55. Epub 2006 Jan 10., web search 3/6/2012, original source: http://www.ncbi.nlm.nih.gov/pubmed/16406335
  
  Abstract: Asbestos was widely used as a building material prior to the 1970's. It is well known that asbestos is a health hazard and its progressive elimination is a priority for pollution prevention.
  
  Asbestos can be transformed to non-hazardous silicate phases by microwave thermal treatment.
  
  The aim of this investigation is to describe the microwave inertization process of asbestos containing waste (ACW) and its recycling in porcelain stoneware tiles, porous single-fired wall tiles and ceramic bricks following industrial manufacture procedure. Inertised asbestos powder was added in the percentages of 1, 3, and 5 wt.% to commercially available compositions and then fired following industrial thermal cycles.
  
  Water absorption and linear shrinkage of the obtained industrial products do not present significant variations with additions up to 5 wt.% of microwave inertised ACW.
• US DoC AMERICAN BUILDING CODE REQUIREMENTS for BRICK [PDF] (1954) US DOC [ American Standard Building Code Requirements For Masonry, U.S. Department of Commerce, National Bureau of Standards, Miscellaneous Publication 211, - retrieved 2023/12/02, original source: govinfo.gov/content/pkg/GOVPUB-C13-064843daf1d708f7529366e16129ee32/pdf/GOVPUB-C13-064843daf1d708f7529366e16129ee32.pdf
  
  Note: the word "asbestos" does not appear in this document.
  
  
• US EPA, ASBESTOS TESTING NOT NEEDED for COMMON MASONRY [PDF] - retrieved 2023/12/02, original source: cfpub.epa.gov/adi/pdf/adi-asbestos-a960020.pdf
  
  Excerpt:
  
  The asbestos NESHAP does not direct an owner or operator to inspect specific materials nor does it list specific suspect materials.
  
  The presence of asbestos and the amount of asbestos in materials may be different from one situation to the next.
  
  Materials such as cinder blocks, mortar, brick, and/or the cement foundation do not typically contain asbestos and would not normally be sampled.
  
  However, if any of the materials are suspected of containing asbestos, they should be sampled and analyzed.
• U.S. EPA, BRICK MANUFACTURING INGREDIENTS / PROCESS - EPA [PDF] U.S. Environmental Protection Agency, original source: epa.gov/ttnchie1/ap42/ch11/final/c11s03.pdf this document describes the ingredients and manufacturing process for common bricks.
  
  Note: the word "asbestos" does not appear in this document.
• Williams, Pamela RD, Amanda D. Phelka, and Dennis J. Paustenbach. "A review of historical exposures to asbestos among skilled craftsmen (1940–2006)." Journal of Toxicology and Environmental Health, Part B 10, no. 5 (2007): 319-377.
  
  Note: this document exemplifies where significant asbestos hazards were found and which sorts of workers were expexted to have higher exposure.
  
  Abstract:
  This article provides a review and synthesis of the published and selected unpublished literature on historical asbestos exposures among skilled craftsmen in various nonshipyard and shipyard settings. The specific crafts evaluated were insulators, pipefitters, boilermakers, masons, welders, sheet-metal workers, millwrights, electricians, carpenters, painters, laborers, maintenance workers, and abatement workers.
  
  Over 50 documents were identified and summarized. Sufficient information was available to quantitatively characterize historical asbestos exposures for the most highly exposed workers (insulators), even though data were lacking for some job tasks or time periods.
  
  Average airborne fiber concentrations collected for the duration of the task and/or the entire work shift were found to range from about 2 to 10 fibers per cubic centimeter (cm3 or cc) during activities performed by insulators in various nonshipyard settings from the late 1960s and early 1970s.
  
  Higher exposure levels were observed for this craft during the 1940s to 1950s, when dust counts were converted from millions of particles per cubic foot (mppcf) to units of fibers per cubic centimeter (fibers/cc) using a 1:6 conversion factor.
  
  Similar tasks performed in U.S. shipyards yielded average fiber concentrations about two-fold greater, likely due to inadequate ventilation and confined work environments; however, excessively high exposure levels were reported in some British Naval shipyards due to the spraying of asbestos.
  
  Improved industrial hygiene practices initiated in the early to mid-1970s were found to reduce average fiber concentrations for insulator tasks approximately two- to five-fold. For most other crafts, average fiber concentrations were found to typically range from <0.01 to 1 fibers/cc ...
  
  

Asbestos in Building Blocks Using Industrial Waste

• Kusiorowski, R., T. Zaremba, and J. Piotrowski. "The potential use of cement–asbestos waste in the ceramic masses destined for sintered wall clay brick manufacture." Ceramics International 40, no. 8 (2014): 11995-12002.
  
  Abstract:
  Asbestos fibers are considered to be carcinogenic and to cause cancer, thus elimination of asbestos-containing materials from the environment is necessary. Currently, asbestos materials are stored in special landfills designed for hazardous wastes. However, this procedure is not a final solution to the problem and an alternative might be thermal recycling.
  
  This paper reports the results of a study on using asbestos-cement slates as an additive to ceramic masses that are typical in the manufacture of sintered clinker wall bricks. Green compacts containing various amounts (0–10 wt%) of asbestos–cement wastes were sintered at temperatures of 1100–1200 °C.
  
  Subsequently, ceramic product properties such as water absorption, open porosity, apparent density, compressive strength and freeze resistance were determined.
  
  The preliminary results of the study indicate that asbestos-containing materials can be used as one of the raw materials in the manufacture of clinker ceramic material, and that the origin of the asbestos–cement used does not have a significant influence on the basic properties of sintered clinker wall bricks.
  
  Main ceramic properties, such as water absorption, compressive strength and freeze resistance, comply with national standards and requirements for construction and road clinker ceramic.
• Obiakor, E. K. "Bricks and ‘asbscrete’ building blocks from asbestos-cement factory wastes." Conservation & Recycling 4, no. 3 (1981): 123-128.
  
  Abstract
  
  Batches of waste material from an asbestos-cement factory were reclaimed and reconstituted into a homogeneous slurry such that the asbestos fibres could be separated from the granular solids by wet sieving. After drying both the fibres and the solids to 3% moisture content it was found that the waste material contained about 12% recoverable asbestos fibres.
  
  The proximate analysis of specimens of both fractions suggested possible utilization as bricks for thermal insulation. Subsequently, it was possible to compact wet mixes of the solids, with small amounts of cement as binder, to bricks of various sizes and shapes which could be used as linings for ovens or low temperature furnaces.
  
  With some admixtures of river sand and a binder, it was also possible to compact the in situ wastes into ‘hollow’ and ‘solid’ building blocks of 225 x 225 x 450 mm which were termed ‘Asbescrete’ Building Blocks.
  
  

Asbestos in Other Clay Products

Asbestos has been reported in art clay (such as Fibro-Clay)[ 37] used in schools and in pottery clay where it occurred in the form of talc added as a flux to lower the firing temperature.

Talc and clay from at least one U.S. mine contained anthophyllite asbestos. It was unclear whether or not this material fell under the aegis of asbestos regulation.[36] The asbestos content of talc depended on where it was mined, and some talcs were asbestos-free[40].

Depending on the quarry source there may be deliberate or accidental inclusion of asbestos in terra cotta tiles such as roofing tiles.

Other clay products that may have had asbestos added in the form of talc or vermiculite (some vermiculite contains asbestos) in addition to art clays, may include clays used as pipe joint seals or insulation, and in the production of firebricks used to line the combustion chambers of heating equipment such as boilers or furnaces, and other school art projects such as paper maches.[38][39]

Asbestos Used in Mortar

Asbestos fibers and possibly asbestos shorts were used as an additive in mortar for use in brick, stone, or other masonry construction as a fiber-strengthener, to improve water resistance, and to improve fire resistance in specialized construction work.

Such fiber reinforced mortar may also have been used for repairing of damage to existing structural coatings such as plastered or stuccoed building exteriors.

At least three manufacturers of asbestos-containing mortar have been identified:

• H.K. Porter Bonding Morter No. 20, produced between 1958 and 1974
• National Gypsum Gold Bond Mortar Mix, produced between 1954 and 1978
• U.S. Gypsum Pyrobar Mortar Mix produced between 1969 and 1972 - for use in fire-resistant coatings

We found other references to use of asbestos in some specialty brick products such as

• Dresser Industries - Metalkase Firebrick and Nuycon firebrick
• GAF - Hearthglow™ or Hearth Glow™ brick boards
• Harbison Walker Refractories Co. ( HW Refractories) Metalkase™ fire brick
• H.K. Porter Corporation - Asbestos firebrick
• Sherwin Williams Paint Co., - Brick & Stucco coating including Brick & Stucco Buff

These are cited at ASBESTOS PRODUCING COMPANIES & TRUSTS

Special uses of asbestos in mortar:

• American Society for Metals, 1965 - Metal-work, p. 53, H.K. Porter Bonding Mortar No. 20. cites
  
  Twenty-five different types of mortars and coating for specialized high temperature applications are detailed in booklet which gives instructions for application.
  
  Mortars include wet and dry type, air setting, and heat setting products made from fireclay, high alumina, silica, or basic refractory materials.
  
  A similar reference is given by Steel Processing and Conversion, Vol. 30-31, Steel Publications, 1944 - Metal Work. on p. 747.
• Bouharoun, Samir, Nordine Leklou, and Pierre Mounanga. "Use of asbestos-free fiber-cement waste as a partial substitute of Portland cement in mortar." Materials and structures 48, no. 6 (2015): 1679-1687.
  
  Abstract excerpts:
  This work aims to study the possibility to use asbestos-free fiber-cement waste in substitution of ordinary Portland cement for the production of mortars. ... This decrease was greater than that observed on mortars containing limestone filler with the same substitution rate of cement. However, the strengths obtained were acceptable for structural applications.
  
  Conclusion excerpt:
  
  The results obtained here indicate that materials containing asbestos can be used as Sorel cement (magnesium oxychloride cement, MOC) fillers. However, thermal pre-treatment is necessary in order to destroy the fibrous, carcinogenic structure of asbestos minerals, such as chrysotile and crocidolite, in the case of this study.
• Castro, Jose, and Antoine E. Naaman. CEMENT MORTAR REINFORCED WITH NATURAL FIBERS [PDF] Journal of Ferrocement 11, no. 4 (1981): 285-301.
• Franzblau, Alfred, Avery H. Demond, Stephanie K. Sayler, Hannah D'Arcy, and Richard L. Neitzel. ASBESTOS-CONTAINING MATERIALS IN ABANDONED RESIDENTIAL DWELLINGS IN DETROIT [PDF] Science of the Total Environment 714 (2020): 136580.
  
  Results
  
  Asbestos was present in about 95% of the sampled ARDs. The most common types of ACMs were flooring, roofing, siding, and duct insulation.
  
  The material containing the greatest fraction of asbestos was duct insulation.
  
  The type of asbestos generally present was chrysotile. Only eight (1%) ARDs contained commercial amphibole asbestos; another 36 contained vermiculite.
  
  The total cost of demolition averaged $13,645 per home, of which 20.1% was asbestos abatement.
• Harbison Walker Refractories Co. ( HW Refractories) Firebrick Micracrete™ refractory cement
• Kusiorowski, Robert, and Teresa Zaremba. THE USE OF ASBESTOS WASTES AS A FILLERS ON SOREL CEMENT [PDF] Ceram. Silik 62 (2018): 31-40.
  
  Abstract: The paper presents the results of research on the usefulness of asbestos wastes as Sorel cement fillers. Chrysotile asbestos and cement-asbestos boards were previously pretreated by heat treatment to destroy the fibrous structure of asbestos.
  
  The raw materials component used in the study contained from 0 to 40 mass % of calcined asbestos wastes. The setting time, compressive strength at 3, 7 and 28 days of ripening, phase composition and microstructure of Sorel cements were examined.
  
  The results of the preliminary studies indicate that calcined asbestos wastes may be used as Sorel cement fillers. Favourable results were obtained with the use of calcined chrysotile asbestos as compared to cement-asbestos.
• Kwon, Jiwoon. IMPACT OF NATURALLY OCCURRING ASBESTOS ON ASBESTOS BAN: REGULATIONS AND EXPERIENCE OF THE REPUBLIC OF KOREA [PDF] International Journal of Environmental Research and Public Health 19, no. 2 (2022): 742.
  
  Excerpts:
  
  Tremolite asbestos was detected in mortar available in the market on 21 September 2020,...
  Regarding the use of asbestos-contaminated dolomite in 2020, less than 1% of asbestos was detected in most mortar samples. ...
  
  The MOEL changed its standard for asbestos content from 0.1% to 1% in April 2015 because it intended to seek legal harmony with the OSH Act, the upper provision that bans substances containing more than 1% asbestos, and it intended to exclude rocks containing less than 1% NOA from the ban.
• Mai, Y. W. "Strength and fracture properties of asbestos-cement mortar composites." Journal of Materials Science 14, no. 9 (1979): 2091-2102.
  
  Abstract: The strength and fracture properties of random asbestos fibre-reinforced cement mortar composites are reported in this paper. The fibre content varies between 5% and 20% by weight. Both the ultimate tensile strength (σt) and the modulus of rupture (σb) increase with increasing fibre-volume fraction.
  
  These results are shown to agree satisfactorily with the law of mixtures modified for randomly oriented short fibre-reinforced composites. The critical stress intensity factor (Kc) and the specific work of fracture (R) have been determined using three-point bend edge-notched beams and grooved double-cantilever-beam (DCB) specimens.
  
  There is generally good agreement between these two physical quantities estimated from the two testpiece geometries.
  
  It is shown that the fibre pull-out mechanism is dominant in the fracture of asbestos cements and that the specific work of fracture can be reasonably well predicted by considering the energies absorbed in both the pull-out and the fibre/matrix interfacial debonding processes.
• Marrocchino, Elena, Virginia Lattao, Negar Eftekhari, Aida Maria Conte, Stefano Franceschini, Salvatore Pepi, Marzia Rizzo, and Carmela Vaccaro. Rationalist architecture in rural villages: petro-morphological CHARACTERIZATION OF NATURAL ASBESTOS FIBERS IN DECORATIVE PLASTERS USED FOR ARTIFICIAL STONES [PDF] Episodes Journal of International Geoscience 43, no. 3 (2020): 893-908.
  
  Abstract excerpt:
  
  The main purpose of this work was to characterize the building materials used in a historical building in Codigoro, a small town near Ferrara, northeastern Italy.
  
  This building was constructed according to the Italian rationalist rules for monumental architecture and is an example of the rationalist architecture found in rural villages, which uses innovative materials and decorations including artificial stone.
  
  The samples analyzed in this work were imitation natural stone, such as “fake travertine” and “fake Ceppo di Grè”, composed of reinforced concrete slabs coated with white mortar. Asbestos minerals have been observed in the fillers in these materials.
  
  Conclusion excerpt:
  
  SEM-EDS and XRD analyses confirmed the presence of asbestos mineral phases, particularly lizardite, both in the concrete used for restoring operations and in samples enriched in ultramafic aggregate. The observed lizardite fibers did not appear to be present at dangerous levels, but potential risks during restoration or collection should be taken into consideration.
• Monfore, G. E. "A review of fiber reinforcement of Portland cement paste, mortar, and concrete." Journal Pca Res & Dev Laboratories (1968).
• Weidner, RB. (1972). Results of U.S.P.H.S. Survey at H.K. Porter Company, Charlotte, North Carolina. (NIOSH/00105830). Weidner, RB.