Lightweight structural concrete provided with various wood properties

• US 7,736,431 B2
• Filed: 12/04/2006
• Issued: 06/15/2010
• Est. Priority Date: 12/02/2005
• Status: Expired due to Fees

• Current Assignee: Thuan H. Bui
• Original Assignee: Thuan H. Bui
• Inventors: Bui, Thuan H.
• Primary Examiner(s): MARCANTONI, PAUL D
• Application Number:
  US11/607,885
• Publication Number:
  US 20070125275A1
• Time in Patent Office: 1,289 Days
• Field of Search: 106/713, 106/644, 106/705, 106/737, 106/DIG.1, 106/DIG.2
• US Class Current: 106/713
• CPC Class Codes: C04B 14/06 Quartz; Sand
• CPC Class Codes: C04B 14/185 expanded
• CPC Class Codes: C04B 16/0641 Polyvinylalcohols; Polyvinylacetates
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 20/0076 characterised by the grain distribution
• CPC Class Codes: C04B 2103/304 Air-entrainers
• CPC Class Codes: C04B 2103/32 Superplasticisers
• CPC Class Codes: C04B 2111/30 Nailable or sawable materials
• CPC Class Codes: C04B 28/04 Portland cements
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y10S 106/01 Fly ash
• CPC Class Codes: Y10S 106/02 Perlite

Abstract

A lightweight structural concrete with screw-ability and nail-ability similar to wood is composed of non-structural and ultra lightweight aggregate such as expanded perlite of a particular size distribution and amount, entrained air cells of another specific size distribution and amount, and dense cementitious composition of a cement binder, a fine grade structural filler no larger than masonry sand grade, a pozzolan, and optional micro-fibers for reinforcement. This structural concrete matrix is optimized to hold 13 gauge T-nails and bugle head wood screws with thread ranging from 8 to 11 threads per inch and diameter of 0.10″ to 0.137″. The resulting concrete will have consistent screw-ability and nail-ability similar that of wood.

Claims

1. A lightweight concrete having compression strength greater than 2500 psi, the lightweight concrete comprising:

(a) 1.05 to 1.75 parts by volume of Portland cement;

(b) 0.75 to 1.25 parts by volume of Class F or Class C fly ash;

(c) 1.15 to 1.85 parts by volume of masonry sand as defined in ASTM C144 or a fine structural filler of size no larger than masonry sand;

(d) an amount of expanded perlite effective to achieve between 17% to 25% volume of the concrete, the expanded perlite having a size distribution mean between 1 mm to 2.5 mm and with at least 75% of the amount of particles falling within +/−

0.6 mm from the center of the size distribution mean;

(e) 0.65 to 1.20 parts by volume of water effective to achieve a water to cement (W/C) ratio in the range of 0.4 to 0.67;

(f) an amount of super-plasticizer effective to produce a target slump; and

(g) an amount of air entrainment admixture effective to produce 3% to 20% entrained air with a size distribution mean no larger than 70% of the size distribution mean of the expanded perlite in the concrete.

2. The lightweight concrete according to claim 1, further comprising a fibrillated polyvinyl alcohol fiber.

3. The lightweight concrete according to claim 1, wherein said 1.15 to 1.85 parts by volume of expanded volume is comprised of a specific distribution in sizes of the expanded perlite, including:

(a) 45-65% its volume is made up of a perlite size from 1 mm to 1.5 mm; and

(b) 35-55% its volume is made up of a perlite size from 150 um to 850 um.

4. The lightweight concrete according to claim 2, wherein said fibrillated polyvinyl alcohol fiber is provided in the amounts of 0.08 to 0.12 parts by volume.

5. A lightweight concrete having a compression strength greater than 2500 psi, the lightweight concrete comprising:

(a) 1.05 to 1.75 parts by volume of Portland cement;

(b) 0.75 to 1.25 parts by volume of Class F or Class C fly ash;

(c) 1.15 to 1.85 parts by volume of masonry sand as defined in ASTM C144 or a fine structural filler of size no larger than masonry sand;

(d) an amount of expanded perlite effective to achieve between 17% to 25% volume of the concrete, the expanded perlite having a size distribution mean between 1 mm to 2.5 mm and with at least 75% of the amount of particles within a 0.6 mm from a center of the size distribution mean;

(e) 0.65 to 1.20 parts by volume of water effective to achieve a water to cement (W/C) ratio in the range of 0.4 to 0.67;

(f) an amount of super-plasticizer effective to produce a target slump; and

(g) an amount of air entrainment admixture effective to produce entrained air with a size distribution mean no larger than 70% of the size distribution mean of the expanded perlite in the concrete.

6. The lightweight concrete according to claim 5, further comprising a fibrillated polyvinyl alcohol fiber.

7. The lightweight concrete according to claim 6, wherein the fibrillated polyvinyl alcohol fiber is provided in the amounts of 0.08 to 0.12 parts by volume.