EP0067183A1 - Cementitious article - Google Patents

Cementitious article

Info

Publication number
EP0067183A1
EP0067183A1 EP19820900082 EP82900082A EP0067183A1 EP 0067183 A1 EP0067183 A1 EP 0067183A1 EP 19820900082 EP19820900082 EP 19820900082 EP 82900082 A EP82900082 A EP 82900082A EP 0067183 A1 EP0067183 A1 EP 0067183A1
Authority
EP
European Patent Office
Prior art keywords
weight
parts
cement
mixture
building article
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19820900082
Other languages
German (de)
French (fr)
Inventor
Reginald Frank Grace
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0067183A1 publication Critical patent/EP0067183A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B24/00Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
    • C04B24/24Macromolecular compounds
    • C04B24/26Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B24/2641Polyacrylates; Polymethacrylates
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/10Compositions or ingredients thereof characterised by the absence or the very low content of a specific material
    • C04B2111/12Absence of mineral fibres, e.g. asbestos

Definitions

  • the present invention relates to building articles form from cementitious materials and more particularly to building articles in the form of sheets formed from such materials.
  • the invention further relates to a process for the formation of such building articles.
  • the present invention consists in a building article comprising from 50 to 200 parts by weight of cement, from 50 to 150 parts by weight of a filler, from 5 to 20 parts by weight of an acrylic modifier on a dry weight basis and from 27 to 30 percent by weight of the cement of water, including any water present in the modifier, which materials have been mixed, formed, into a desired shape, compressed at a pressure of at least 1200 p.s.i., and cured.
  • the present invention further consists in a process for forming a building article comprising mixing together from 50 to 200 parts by weight of cement, from 50 to 150 parts by weight of a filler, from 5 to 20 parts by weight of an acrylic modifier on a dry weight basis and from 27 to 30 percent by weight of the cement of water, including any water present in the modifier, forming the mixture into a desired shape, compressing the mixture at a pressure of at least 1200 p.s.i. and curing the compressed mixture.
  • the building articles according to the present invention may comprise sheets or panels, blocks or formed shapes for use as guttering, ducting or the like. It is however in the area of sheets and panels in which the present articles have particular applicability due to the high flexural strength exhibited by these articles when made by the process according to this invention. Sheets having a thickness of from 1/4" to 1 1/2" for use as flooring materials are paticularly advantageously made from the present materials.
  • the cement used in the present invention is preferably conventional Portland cement.
  • the cement should constitute from 50 to 200 parts by weight of the articles and preferably 80 to 120 parts by weight.
  • the cement content is most preferably 100 parts by weight.
  • the filler preferably comprises a crystalline or non crystalline silicate such as sand or crushed glass however other fine fillers such as fly ash, rice hull ash, crushed quartz and the like could equally well be used.
  • a preferred filler is a crushed naturally ocurring volcanic glass known as perlite.
  • the filler may all be fine grade material, however, it is preferable to use a mixture of fine filler and coarser material.
  • Advantageously 75 parts of fine material to 25 parts of 6/10 mesh material is used.
  • the filler should be present in an amount of from 50 to 150 parts by weight, preferably from 75 to 125 parts by weight. It is most preferable that the filler comprises 100 parts by weight.
  • the acrylic modifier is one of a range of commercially available cement additives which constitutes powders or emulsions of acrylic acid polymers and copolymers. These modifiers increase the impact and flexural strength of cement as well as improving its adhesion to a variety of substrates.
  • Preferred examples of acrylic modifiers are the products MC76 and B60A sold by Rohm and Haas.
  • the modifier is present in the article in an amount of 5 to 20 parts by weight of modifier solids. If the modifier is an emulsion the water content is included in the total water content in the articles. More preferably the modifier is present in an amount of 8 to 14 parts by weight and most preferably 11 part by weight.
  • the amount of water in the mixture used to form the articles according to this invention should be from 27 to 30 percent by weight of the cement, including any water present in the acrylic modifier.
  • the amount of water is sufficiently low that no water will be exuded when the mixture is compressed while being sufficient to bring about the appropriate hydration reaction involved in the setting of the cement content of the article.
  • the articles according to this invention may advantageously include a reinforcing material such as a metal or plastic mesh or fibrous material such as fibres of cellulose or glass. This reinforcing material is preferably applied as a layer between two layers of the ceme ntitious mixture prior to the formed article being compressed.
  • the process according to the invention is preferably carried out by mixing the filler with from 20 to 50% of the total water content and at least a proportion of the acrylic modifier and then adding the cement to form an almost "dry" granular mixture which is flowable.
  • Half of this flowable mixture is then put into a suitable mould and levelled.
  • a reinforcing mesh of steel wire is preferably laid on this layer of cementitious mixture and half of the remaining water sprayed in a fine spray evenly over the layer.
  • the remaining mixture is then placed over the reinforcing mesh and levelled.
  • the remaining water is then sprayed onto the top of the mixture and the whole mould passed into a press which compresses the formed mixture at a pressure of at least 1200 p.s.i.
  • the wire mesh may be supported in a suitable mould and all of the granular cementitious mixture added to the mould and vibrated down through the wire mesh into a uniform screeded condition. The remaining water is then added and the material pressed as described above. In tliis embodiment of the invention it is desirable to add a surfactant to the water to assist in wetting the cementitious material. After the article has been formed and compressed it must be cured. The article will generally have acquired sufficient green strength for the mould to be removed in a matter of hours, however, a period of from seven to twenty eight days is required for sheets formed by the present process to acquire sufficient strength to be freely handled.
  • Panels formed by the process according to this invention have been found to be flame resistant and non-flamable, to have a very low moisture absorbtion after initial curing and to have a high flexural strength.
  • a flooring sheet was formed from the following materials:
  • Fine sand - 75 parts by weight Fine sand - 75 parts by weight.
  • Acrylic modifier (MC-76 Rohm and Haas) (dry weight basis) 11 parts by weight.
  • the acrylic modifier was measured out and mixed with 20% of the total water requirement.
  • a reinforcing mesh of steel 4 ram. wires having a grid spacing of 200 mm. and a size of 1100 ⁇ 2300 mm was placed on the levelled layer of mixture. 7. 50% of the remaining water was sprayed on the mixture in the mould in a fine spray evenly applied over the whole layer.
  • the mould was introduced into an hydraulic press and the mixture in the mould compressed at a pressure of 2000 p.s.i. for one minute.
  • the sheets so formed showed a water absorption of only 5% by weight after 72 hours immersion in water.
  • the cured sheets had a density of 2.32 grams/c.c. and a mass of 32.5 kg per square metre.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

Variante a de haute resistance a la flexion des articles de fibrociment. La variante consiste en un article de ciment comprenant: 1) 50 a 200 parties en poids de ciment, 2) 50 a 150 parties en poids d'un materiau de remplissage; 3) 5 a 20 parties en poids d'un modificateur acrylique calcule sur une base ponderale a sec; 4) 27 a 30% en poids d'eau par rapport au ciment. Le materiau de remplissage peut etre du sable ou un autre silicate cristallin ou non cristallin, du verre, des cendres volantes, des cendres de cosses de riz ou du quartz concasse. Le modificateur acrylique est choisi parmi une gamme de poudres ou d'emulsions de copolymeres et de polymeres d'acide acrylique. Les articles sont formes en melangeant les ingredients, en leur donnant la forme desiree, en comprimant le melange a une pression d'au moins 1200 p.s.i et en les laissant durcir.Variant with high flexural strength of fiber cement articles. The variant consists of an article of cement comprising: 1) 50 to 200 parts by weight of cement, 2) 50 to 150 parts by weight of a filling material; 3) 5 to 20 parts by weight of an acrylic modifier calculated on a dry weight basis; 4) 27 to 30% by weight of water relative to the cement. The filling material may be sand or other crystalline or non-crystalline silicate, glass, fly ash, rice husk ash or crushed quartz. The acrylic modifier is chosen from a range of powders or emulsions of copolymers and polymers of acrylic acid. The articles are formed by mixing the ingredients, giving them the desired shape, compressing the mixture to a pressure of at least 1200 p.s.i and allowing them to harden.

Description

CEMENTITIOUS ARTICLE TECHNICAL FIELD The present invention relates to building articles form from cementitious materials and more particularly to building articles in the form of sheets formed from such materials. The invention further relates to a process for the formation of such building articles. BACKGROUND ART
It has been conventional to form building articles such as cladding sheets and the like from asbestos cement which is a cementitious composition reinforced with asbestos fibres. In recent years it has been recognised that the extraction an processing of asbestos constitutes a serious health hazard an it is thought that the handling of asbestos containing products, including asbestos cement articles, could also be deleterious to human health. For this reason efforts have been made to find materials which exhibit the desirable properties of asbestos cement compositions without the health hazard of those asbestos cement compositions. These desirable properties include cheapness, relative ease of working and high flexural strength. The present invention is designed to offer an alternative material for use in place of asbestos cement in at least some of its applications. DISCLOSURE OF INVENTION
The present invention consists in a building article comprising from 50 to 200 parts by weight of cement, from 50 to 150 parts by weight of a filler, from 5 to 20 parts by weight of an acrylic modifier on a dry weight basis and from 27 to 30 percent by weight of the cement of water, including any water present in the modifier, which materials have been mixed, formed, into a desired shape, compressed at a pressure of at least 1200 p.s.i., and cured.
The present invention further consists in a process for forming a building article comprising mixing together from 50 to 200 parts by weight of cement, from 50 to 150 parts by weight of a filler, from 5 to 20 parts by weight of an acrylic modifier on a dry weight basis and from 27 to 30 percent by weight of the cement of water, including any water present in the modifier, forming the mixture into a desired shape, compressing the mixture at a pressure of at least 1200 p.s.i. and curing the compressed mixture.
The building articles according to the present invention may comprise sheets or panels, blocks or formed shapes for use as guttering, ducting or the like. It is however in the area of sheets and panels in which the present articles have particular applicability due to the high flexural strength exhibited by these articles when made by the process according to this invention. Sheets having a thickness of from 1/4" to 1 1/2" for use as flooring materials are paticularly advantageously made from the present materials.
The cement used in the present invention is preferably conventional Portland cement. The cement should constitute from 50 to 200 parts by weight of the articles and preferably 80 to 120 parts by weight. For use in flooring sheets the cement content is most preferably 100 parts by weight.
The filler preferably comprises a crystalline or non crystalline silicate such as sand or crushed glass however other fine fillers such as fly ash, rice hull ash, crushed quartz and the like could equally well be used. A preferred filler is a crushed naturally ocurring volcanic glass known as perlite. The filler may all be fine grade material, however, it is preferable to use a mixture of fine filler and coarser material. Advantageously 75 parts of fine material to 25 parts of 6/10 mesh material is used. The filler should be present in an amount of from 50 to 150 parts by weight, preferably from 75 to 125 parts by weight. It is most preferable that the filler comprises 100 parts by weight.
The acrylic modifier is one of a range of commercially available cement additives which constitutes powders or emulsions of acrylic acid polymers and copolymers. These modifiers increase the impact and flexural strength of cement as well as improving its adhesion to a variety of substrates. Preferred examples of acrylic modifiers are the products MC76 and B60A sold by Rohm and Haas. The modifier is present in the article in an amount of 5 to 20 parts by weight of modifier solids. If the modifier is an emulsion the water content is included in the total water content in the articles. More preferably the modifier is present in an amount of 8 to 14 parts by weight and most preferably 11 part by weight.
The amount of water in the mixture used to form the articles according to this invention should be from 27 to 30 percent by weight of the cement, including any water present in the acrylic modifier. The amount of water is sufficiently low that no water will be exuded when the mixture is compressed while being sufficient to bring about the appropriate hydration reaction involved in the setting of the cement content of the article.
It is preferable that a surfactant should be added to th water to aid the wetting of the filler and the cement. The articles according to this invention may advantageously include a reinforcing material such as a metal or plastic mesh or fibrous material such as fibres of cellulose or glass. This reinforcing material is preferably applied as a layer between two layers of the ceme ntitious mixture prior to the formed article being compressed.
The process according to the invention is preferably carried out by mixing the filler with from 20 to 50% of the total water content and at least a proportion of the acrylic modifier and then adding the cement to form an esentially "dry" granular mixture which is flowable. Half of this flowable mixture is then put into a suitable mould and levelled. A reinforcing mesh of steel wire is preferably laid on this layer of cementitious mixture and half of the remaining water sprayed in a fine spray evenly over the layer. The remaining mixture is then placed over the reinforcing mesh and levelled. The remaining water is then sprayed onto the top of the mixture and the whole mould passed into a press which compresses the formed mixture at a pressure of at least 1200 p.s.i. preferably between 1200 and 4000 p.s.i., most preferably at or about 3000 p.s.i. If necessary a panel may be placed over the formed mixture prior to its being compressed to ensure that the pressure is applied evenly over the whole article. In another embodiment of the invention the wire mesh may be supported in a suitable mould and all of the granular cementitious mixture added to the mould and vibrated down through the wire mesh into a uniform screeded condition. The remaining water is then added and the material pressed as described above. In tliis embodiment of the invention it is desirable to add a surfactant to the water to assist in wetting the cementitious material. After the article has been formed and compressed it must be cured. The article will generally have acquired sufficient green strength for the mould to be removed in a matter of hours, however, a period of from seven to twenty eight days is required for sheets formed by the present process to acquire sufficient strength to be freely handled.
Panels formed by the process according to this invention have been found to be flame resistant and non-flamable, to have a very low moisture absorbtion after initial curing and to have a high flexural strength. BEST MODE OF CARRYING OUT THE INVENTION
Hereinafter given by way of example only is a preferred embodiment of the present invention.
A flooring sheet was formed from the following materials:
Cement (Goliath "A") - 100 parts by weight.
Fine sand - 75 parts by weight.
Coarse sand - 100 parts by weight.
Acrylic modifier (MC-76 Rohm and Haas) (dry weight basis) 11 parts by weight.
Water - 29.6 parts by weight. . Surfactant - 0.01 parts by weight in the water. The sheet was formed by the following process:-
1. The sand was measured and placed into a conventional concrete mixer.
2. The acrylic modifier was measured out and mixed with 20% of the total water requirement.
3. The water/acrylic modifier mixture was added to the sand in the mixer while the mixer was operating.
4. The cement was then measured and introduced into the operating mixer to produce a "dry" flowable granular moss.
5. Half of the mixture was then placed in a mould comprising a base board on which was placed a rectangular frame defining a space 1200 mm. × 2400 mm. × 13 mm. The mixture was levelled in the frame on the base board.
6. A reinforcing mesh of steel 4 ram. wires having a grid spacing of 200 mm. and a size of 1100 × 2300 mm was placed on the levelled layer of mixture. 7. 50% of the remaining water was sprayed on the mixture in the mould in a fine spray evenly applied over the whole layer.
8. The remaining cementitious mixture was placed in the mould and levelled to produce a void free screened surface.
9. The remaining water was sprayed onto the top surface of the mixture in the mould as in step 7.
10. A pressure levelling board 1200 mm. × 2400 mm. was place over the cementitious mixture in the mould.
11. The mould was introduced into an hydraulic press and the mixture in the mould compressed at a pressure of 2000 p.s.i. for one minute.
12. The mould was removed from the press and the pressure levelling board immediately removed.
13. After 2 hours the mould frame was removed from around the formed sheet leaving the sheet on the base board.
14. After 12 hours the formed cementitious sheet was removed from the base board and stacked horizontally with other similar sheets: a plastic sheet was placed between juxtapose cementitious sheets.
15. After seven days the cementitious sheets were found to be able to be freely handled, however, it was twenty eight days before the maximum strength was developed in the sheets.
It was found that the sheets so formed showed a water absorption of only 5% by weight after 72 hours immersion in water. The cured sheets had a density of 2.32 grams/c.c. and a mass of 32.5 kg per square metre.

Claims

The claims defining the invention are as follows:-
1. A building article comprising from 50 to 200 parts by weight of cement, from 50 to 150 parts by weight of a filler, from 5 to 20 parts by weight of an acrylic modifier on a dry weight basis and from 27 to 30 percent by weight of the cement of water, including any water present in the modifier, which materials have been mixed, formed into a desired shape, compressed at a pressure of at least 1200 p.s.i., and cured.
2. A building article as claimed in claim 1 in which the cement comprises from 80 to 120 parts by weight of the article.
3. A building article as claimed in claim 1 or claim 2 in which the filler comprises sand, crushed glass or another crystalline or non-crystalline silicate.
4. A building article as claimed in any one of claims 1 to
3 in which the filler is present in an amount of from 75 to 125 parts by weight.
5. A building article as claimed in any one of claims 1 to
4 in which the acrylic modifier is an aqueous emulsion.
6. A building article as claimed in any one of claims 1 to 4 in which the acrylic modifier is present in an amount of 8 to 14 parts by weight on a dry weight basis.
7. A building article as claimed in any one of claims 1 to
6 in which the building article additionally contains a reinforcing material.
8. A building article as claimed in any one of claims 1 to
7 in which the building article is compressed at a pressure between 1200 and 4000 p.s.i. prior to being cured.
9. A building article substantially as hereinbefore described with reference to the example given herein.
10. A process for forming a building article comprising mixing together from 50 to 200 parts by weight of cement, from 50 to 150 parts by weight of a filler, from 5 to 20 parts by weight of an acrylic modifier on a dry weight basis and from 27 to 30 percent by weight of the cement of water including any water present in the modifier, forming the mixture into a desired shape, compressing the mixture at a pressure of at least 1200 p.s.i. and curing the compressed mixture.
11. A process for forming a building article as claimed in claim 10 in which the filler is mixed with from 20 to 50% of the total water content and at lest a proportion of the acrylic modifier and the cement then added to form a flowable "dry" grannular mixture, the mixture is placed in a mould and the remaining water sprayed onto the mixture, and the mixture is compressed and cured.
12. A process for forming a building article substantially as hereinbefore described with reference to the example given herein.
EP19820900082 1980-12-22 1981-12-22 Cementitious article Withdrawn EP0067183A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPE703380 1980-12-22
AU7033/80 1980-12-22

Publications (1)

Publication Number Publication Date
EP0067183A1 true EP0067183A1 (en) 1982-12-22

Family

ID=3768894

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19820900082 Withdrawn EP0067183A1 (en) 1980-12-22 1981-12-22 Cementitious article

Country Status (3)

Country Link
EP (1) EP0067183A1 (en)
AU (1) AU7879481A (en)
WO (1) WO1982002195A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111848079A (en) * 2020-07-01 2020-10-30 江苏大丰新安德矿业有限公司 High-plasticity cement product doped with iron ore concentrate powder and preparation method thereof

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2075708A1 (en) * 1990-02-12 1991-08-13 Anthony B. Venn Method, apparatus and composition
CA2043094C (en) * 1990-06-06 1997-02-11 Robert L. Vecchio Cement based compositions having elastomeric properties, and method of manufacture
GB2255116A (en) * 1991-04-22 1992-10-28 Shimizu Construction Co Ltd Sound-insulating concrete wall.
ES2163349B1 (en) * 1999-01-15 2003-04-01 Gasteiz Desarrollo Ind E Ingen MANUFACTURING PROCEDURE FOR THE PRODUCTION OF ACOUSTIC PROTECTION PANELS AND OTHER SIMILAR CHARACTERISTICS FOR THE RESIDENTIAL AND PUBLIC WORKS SECTORS.

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1471481A1 (en) * 1963-04-12 1968-12-12 Toa Gosei Kagaku Kogyo Kabushi Method for rapid hardening of cement
US3196122A (en) * 1964-02-14 1965-07-20 Master Mechanics Company Cementitious compositions containing acrylic ester polymers
GB1159377A (en) * 1968-03-22 1969-07-23 Exxon Research Engineering Co Cementitious Compositions for Bituminous Substrates
GB1101204A (en) * 1965-08-12 1968-01-31 Ici Ltd Cementing compositions
CH481849A (en) * 1967-05-03 1969-11-30 Chemische Handels Cie Anstalt Process for improving the mechanical properties of concrete and mortar masses
US3538036A (en) * 1968-04-25 1970-11-03 Harry T Campbell Sons Corp Concrete composition containing polymeric acrylic resin
GB1346779A (en) * 1971-02-12 1974-02-13 Elkalite Ltd Cementitious articles

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8202195A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111848079A (en) * 2020-07-01 2020-10-30 江苏大丰新安德矿业有限公司 High-plasticity cement product doped with iron ore concentrate powder and preparation method thereof

Also Published As

Publication number Publication date
AU7879481A (en) 1982-07-01
WO1982002195A1 (en) 1982-07-08

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