Thermally adaptive ductile concrete

Patent metadata

Field	Value
Publication number	US-9512344-B2
Application number	US-201414768049-A
Country	US
Kind code	B2
Filing date	Feb 14, 2014
Priority date	Feb 15, 2013
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

A Thermally Adaptive Ductile Concrete (PCM-ECC) having a tensile ductility ceramic with 5 times the thermal resistance, 2 times the specific heat capacity, and 400 times the tensile strain capacity of regular concrete.

First claim

What is claimed is:

1. A fiber-reinforced cementitious composite comprising:
a binder of cement, class F fly ash, and water;
a plurality of uniformly distributed oil-coated polyvinyl alcohol (PVA) or polyethylene (PE) fibers at 1.5% to 3% of the total volume;
a sand with average diameter of about 100 microns;
a microencapsulated paraffin wax that changes a state of matter at a temperature between 18 and 26 degrees Celsius; and
a water reducing admixture in sufficient quantity to obtain a mini-cone flow rate of a pre-cured fiberless matrix of the fiber-reinforced cementitious composite between 24 and 33 seconds,
wherein said composite having an ultimate tensile strength of at least 4 MPa and exhibiting a compressive strength of about 28 MPa.

2. The fiber-reinforced cementitious composite of claim 1 wherein said microencapsulated paraffin wax is not greater than about 10% of the total mass of the composite.

3. The fiber-reinforced cementitious composite of claim 1 wherein said plurality of fibers have an average diameter of 30-50 microns and an average length of 8-12mm.

4. The fiber-reinforced cementitious composite of claim 1 wherein said binder is a Portland cement.

5. The fiber-reinforced cementitious composite of claim 1 wherein said binder is a Type 1 Portland cement.

6. The fiber-reinforced cementitious composite of claim 1 wherein a weight ratio of water to binder is between 0.2 and 0.4.

7. The fiber-reinforced cementitious composite of claim 1 wherein a weight ratio of water to binder is 0.3.

8. The fiber-reinforced cementitious composite of claim 1 wherein a specific heat capacity is between 1000-2000 J/Kg.K when the composite is at temperatures below 20 or above 25 degrees Celsius and a peak specific heat capacity at 23 degrees Celsius is 20% higher than the specific heat capacity value average.

9. The fiber-reinforced cementitious composite of claim 1 wherein a thermal conductivity of the composite is 20% lower than that of a composite without said microencapsulated paraffin wax.

10. The fiber-reinforced cementitious composite of claim 1 wherein said composite has an average specific heat capacity of 1600 J/Kg.K and a peak specific heat capacity of 1900-2000 J/Kg.K at a phase change temperature of 23° C.

11. The fiber-reinforced cementitious composite of claim 1 wherein said composite having an average thermal conductivity between 0.30 and 0.50 W/m.K.

12. The fiber-reinforced cementitious composite of claim 1 wherein said composite having an ultimate tensile strength of about 4.3 MPa.

13. The fiber-reinforced cementitious composite of claim 1 wherein said composite exhibiting strain-hardening behavior resulting in a tensile strain capacity of at least 0.5%.

14. The fiber-reinforced cementitious composite of claim 1 wherein said composite exhibiting strain-hardening behavior resulting in a tensile strain capacity between 3% and 5%.

15. The fiber-reinforced cementitious composite of claim 1 wherein said composite exhibiting a density of about 1650 kg/m 3 .

Assignees

• Univ Michigan Regents

Inventors

• Li Victor C
• Desai Devki

Classifications

• C04B16/00

  Use of organic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of organic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone · CPC title

• C04B16/06

  fibrous · CPC title

• C04B2201/32

  for the thermal conductivity, e.g. K-factors · CPC title

• C04B14/062

  Microsilica, e.g. colloïdal silica (preparing microsilica slurries or suspensions C04B18/148) · CPC title

• C04B2103/32

  Superplasticisers · CPC title