Process for accelerating hardening of cement with fibre-reinforced and cement-bound plates

• US 4,746,481 A
• Filed: 01/22/1986
• Issued: 05/24/1988
• Est. Priority Date: 01/23/1985
• Status: Expired due to Fees

• Current Assignee: Nyugatmagyarorszagi Fagazdasagi Kombinat Szombathely
• Original Assignee: Nyugatmagyarorszagi Fagazdasagi Kombinat
• Inventors: Schmidt, Erno
• Primary Examiner(s): DERRINGTON, JAMES H
• Application Number:
  US06/821,263
• Time in Patent Office: 853 Days
• Field of Search: 264/82, 264/333, 264/DIG. 43
• US Class Current: 264/82
• CPC Class Codes: B28B 1/52 specially adapted for producing articles from mixtures containing fibres, e.g. asbestos cementby wrapping on to mandrels B28B1/42
• CPC Class Codes: B28B 3/00 Producing shaped articles from the material by using presses shaping on moving conveyors B28B5/00; Presses specially adapted therefor presses in general B30B
• CPC Class Codes: B28B 7/44 for treating with gases or degassing, e.g. for de-aerating treating with hot gases or vapour B28B7/42
• CPC Class Codes: C04B 20/0048 Fibrous materials
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 40/0231 Carbon dioxide hardening
• CPC Class Codes: Y10S 264/43 Processes of curing clay and concrete materials

Abstract

The invention relates to a process for accelerating hardening of cement in fibre-reinforced and cement-bond plates and solids respectively. The essence of the process lies in that a composition known in itself containing water, fibrous material and cement is placed between the pressure plates of a press, compressed, simultaneously with pressing a flange of increased density is formed on the profile to be produced; the medium between the gasproof or quasi gasproof boundary surface is carbonized wih CO₂ gas thereafter pressure is reduced.

Claims

1. A process for accelerating the hardening of cement in a composition containing water, cement and fibrous material, comprising the steps of:

(a) forming said composition into a predetermined shape having an outer perimeter portion extending about the outer perimeter of said predetermined shape and an internal portion within the confines of said outer portion,

(b) positioning said predetermined shape of said composition between the pressure plates of a press,

(c) utilizing said pressure plates to compress said internal portion of the formed shape of said composition to a first predetermined density,

(d) utilizing said pressure plates to compress said outer perimeter portion of the formed shaped of said composition to a second predetermined density, said second predetermined density being greater than said first predetermined density and being of sufficient density to compress said outer perimeter portion to a gas leak tight condition,

(e) applying CO₂ to said internal portion of the formed shape of said composition, whereby said CO₂ is confined to be within said internal portion by said pressure plates and said gas leak tight compressed outer perimeter portion.

2. The method according to claim 1, further characterized by increasing the compression of said outer perimeter portion by forming said outer perimeter portion to a thickness which is greater than the thickness of said internal portion.

3. The method according to claim 1, further characterized by increasing the compression of said outer perimeter portion by forming an area of increased compressive force produced by said pressure plates and applied to said outer perimeter portion.

4. The method according to claim 1, further characterized by applying overpressurized CO₂ to said internal portion to displace air therefrom.

5. The method according to claim 1, further characterized by after applying CO₂ reducing the compressive forces of said pressure plates.