GB2168692A - Treatment of cementitious products - Google Patents

Treatment of cementitious products Download PDF

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Publication number
GB2168692A
GB2168692A GB08431741A GB8431741A GB2168692A GB 2168692 A GB2168692 A GB 2168692A GB 08431741 A GB08431741 A GB 08431741A GB 8431741 A GB8431741 A GB 8431741A GB 2168692 A GB2168692 A GB 2168692A
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GB
United Kingdom
Prior art keywords
water
products
flexural strength
cement
polymeric material
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.)
Granted
Application number
GB08431741A
Other versions
GB8431741D0 (en
GB2168692B (en
Inventor
Alan William Atkinson
Anthony Thomas Walsh
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.)
T&N Materials Research Ltd
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T&N Materials Research Ltd
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 T&N Materials Research Ltd filed Critical T&N Materials Research Ltd
Priority to GB08431741A priority Critical patent/GB2168692B/en
Publication of GB8431741D0 publication Critical patent/GB8431741D0/en
Publication of GB2168692A publication Critical patent/GB2168692A/en
Application granted granted Critical
Publication of GB2168692B publication Critical patent/GB2168692B/en
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/60—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only artificial stone
    • C04B41/61—Coating or impregnation
    • C04B41/65—Coating or impregnation with inorganic materials
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00241—Physical properties of the materials not provided for elsewhere in C04B2111/00
    • C04B2111/00301—Non-porous materials, e.g. macro-defect free [MDF] products

Abstract

Shaped products (e.g. sheets) comprising a matrix of water-insolubilised organic polymeric material (e.g. a hydrolysed vinyl acetate polymer) filled with water-insoluble inorganic material (for example, a set hydraulic cement), as described for example in European Patent Publication 55 035 (ICI), have an unusually high flexural strength, above 40 MPa, but this falls considerably when the products remain in prolonged contact with water. By the invention, the extent to which flexural strength of such products is lost on contact with water is reduced by treatment with an aqueous solution of boric acid or a borate.

Description

SPECIFICATION Shaped products comprising a matrix of water-insolubilised organic polymeric material filled with water-insoluble inorganic material This invention relates to shaped products comprising a matrix of water-insolubilised organic polymeric material filled with water-insoluble inorganic material.
In European Patent Publication 55035 of Imperial Chemical Industries Plc there are described shaped cementitious products of flexural strength above 40MPa produced by the setting of a cementitious composition comprising hydraulic cement, water in an amount not more than 25% by weight of the composition, and a water-soluble or -dispersible organic polymer or copolymer in an amount of 1 to 15% by weight of the hydraulic cement.The cement and the organic polymer material are selected so that a test composition comprising 100 parts by weight of cement, 5 parts by weight of the organic polymeric material and 16 parts by weight of water when extruded in a capillary rheometer undergoes an increase of at least 25% in shear stress when a ten-fold increase in the shear rate of the test composition is effected when the shear rates are measured are within the range of 0.1 to 5 second~'.
The organic polymeric material, which serves as a processing acid during preparation of the cementitious composition by high-shear mixing, is preferably a hydrolysed vinyl acetate polymer or copolymer, particularly hydrolysed poly(vinyl acetate), the degree of hydrolysis being preferably at least 50%: ie 50% of the vinyl acetate units in the polymer or copolymer are hydrolysed to the alcohol form.
The flexural strength of the shaped products is improved by ensuring that only a very small proportion, preferably not more than 2%, of the total volume of the set product, includes pores having a maximum dimension exceeding 100 microns as measured by quantitative microscopy, as described for example in an earlier European Patent Pulbication (21682) of Imperial Chemical Industries Plc. The maintenance of high flexural strength in the shaped product is assisted by including a high-boiling polyol for example, glycerol, an alkylene glycol or a polyalkylene glycol, in the composition before setting.
In experimenting with the products just considered we have found that their flexural strength, although remarkably high, falls considerably when they are allowed to remain in prolonged contact with water. For example, as illustrated later in this specification, a product of initial flexural strength 120 MPa may, on immersion in water at ambient temperature, deteriorate to only half that strength in three days.
The present invention is concerned with reducing the extent to which the flexural strength of such products, and others like them, is lost on contact with water.
In arriving at the invention, we have to some extent been helped by recasting the terms in which we have thought about the products concerned. We have now come to regard them as essentially comprising a matrix of water-insolubilised organic polymeric material filled with waterinsoluble inorganic material, rather than as a matrix of set hydraulic cement in which the organic polymeric material that is present contributes little once it has served its purpose during processing. The organic polymeric material employed in making the cementitious composition loses its water-insolubility or -dispersibility as a result of the action upon it of the water-soluble metallic compounds that are present in the hydraulic cement or are released from the cement during setting.However, it has occurred to us that in that insolubilised state the organic polymeric material may not be free from the possibility of degradation by adsorption of water, with consequent softening, swelling and loss of strength in the shaped product itself.
According to the invention the extent to which the flexural strength of such shaped products decreases on contact with water is reduced by treatment with an aqueous solution of boric acid or a borate.
We have also observed that such treatment may also have the effect of reducing the tendency of the shaped products to form an unattractive soft, crumbly surface on contact with water.
The invention is applicable to the treatment not only of products comprising set hydraulic cement, such as a calcium silicate cement or an aluminous cement, but also of those products in which the water-insoluble inorganic material filling the matrix of water-insolubilised organic polymer material is non-cementitious, for example aluminium oxide or silica. Such shaped products are described in European Patent Publication 96 522 of Imperial Chemical Industries Plc, and are made by shaping a mouldable composition comprising a homogeneous mixture of (a) a particulate material insoluble in and substantially unreactive with water, (b) a water-soluble or water-dispersible organic polymeric material and (c) water.
The composition comprises also an additive capable of reacting with the polymeric material to render it insoluble in water; and ingredients (a), (b) and (c) are present in the composition in the volume proportions 40-90%, 2-25% and not more than 60% respectively. As aiready indicated, alumina and silica are examples of ingredients (a); and aluminium hydroxy chloride is an example of the additive.
The invention is further illustrated by the foilowing Example: Example Following generally Example 1 in Imperial Chemical Industries Plc European Patent publication 55035, a mixture was prepared of the following ingredients: Parts by weight Cement Fondu Lafarge 100 (a calcium aluminate cement of 40% Awl203 content) Hydrolysed poly(vinyl) acetate) 7 (GOHSENOL KH 17S; about 80% hydrolysed) Glycerol 0.7 Water 11.5 The ingredients were first blended in a planetary mixer to a damp-crumb consistency. The material was then transferred to a twin-roll mill, and within 1 minute had become formed into a sheet with the consistency of a rubbery dough. This cement sheet was then faced with thin polyethylene sheet and placed in a pre-warmed mould (250 mmX250 mm).
A pressure of 3.5 MPa was then applied for 10 minutes while the mould was kept at a temperature of 80"C. This was sufficient to harden the composition, and the sheet was removed and stored at ambient temperature and 100% relative humidity for seven days, to allow hydration of the cement.
Once hardened, the cement sheet was cut into 100 mmX 15 mmX3 mm specimens suitable for flexural strength testing. One-third of the specimens were allowed to air-dry, one-third were immersed in water (at 20"C) for 3 days and the remaining third was immersed in 3% aqueoous boric acid (H3BO3; at 10 ) for 3 days and then rinsed in water. Strengths were then measured by 3-point bending.
The results were as follows.
Appearance and surface texture Flexural Strength (MPa) samples tested dry \ smooth and hard 1 120 samples tested wet swollen patches, saft and 61 crumbly surface samples treated with boric acid and . tested wet Thus, besides reducing loss of strength in the product when wet, boric acid also improved the appearance and texture of the surface of the product.

Claims (5)

1. A method of treating a shaped product comprising a matrix of water-insolubilised organic polymer material filled with water-insoluble inorganic material, to reduce the extent in which flexural strength decreases on contact with water, in which the shaped product is treated with an aqueous solution of boric acid or a borate.
2. A method according to claim 1, in which the water-insoluble inorganic material is a set hydraulic cement.
3. A method according to claim 2, in which the hydraulic cement is an aluminous cement.
4. A method according to claim 1, 2 or 3, in which the organic polymeric material is a hydrolysed vinyl acetate polymer or copolymer.
5. A method according to claim 1, substantially as illustrated with reference to the Example herein.
GB08431741A 1984-12-15 1984-12-15 Treatment of cementitious products Expired GB2168692B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08431741A GB2168692B (en) 1984-12-15 1984-12-15 Treatment of cementitious products

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08431741A GB2168692B (en) 1984-12-15 1984-12-15 Treatment of cementitious products

Publications (3)

Publication Number Publication Date
GB8431741D0 GB8431741D0 (en) 1985-01-30
GB2168692A true GB2168692A (en) 1986-06-25
GB2168692B GB2168692B (en) 1988-05-25

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Family Applications (1)

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GB08431741A Expired GB2168692B (en) 1984-12-15 1984-12-15 Treatment of cementitious products

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0332388A1 (en) * 1988-03-08 1989-09-13 Marley Tile AG Cementitious product

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2049719A (en) * 1979-05-21 1980-12-31 Vernier Ciment Portland Compositions for Coating Concrete, Mortar or Plaster Substrates
EP0055035A1 (en) * 1980-12-22 1982-06-30 Imperial Chemical Industries Plc Cementitious composition and cementitious product of high flexural strength

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2049719A (en) * 1979-05-21 1980-12-31 Vernier Ciment Portland Compositions for Coating Concrete, Mortar or Plaster Substrates
EP0055035A1 (en) * 1980-12-22 1982-06-30 Imperial Chemical Industries Plc Cementitious composition and cementitious product of high flexural strength

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0332388A1 (en) * 1988-03-08 1989-09-13 Marley Tile AG Cementitious product
WO1989008627A1 (en) * 1988-03-08 1989-09-21 Marley Tile A.G. Cementitious products
US5147459A (en) * 1988-03-08 1992-09-15 Marley Tile Ag Cementitious products

Also Published As

Publication number Publication date
GB8431741D0 (en) 1985-01-30
GB2168692B (en) 1988-05-25

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