Lightweight aggregate ultra-high performance concrete (UHPC) and preparation method thereof

Patent metadata

Field	Value
Publication number	US-11447419-B2
Application number	US-201917053424-A
Country	US
Kind code	B2
Filing date	Dec 30, 2019
Priority date	Dec 30, 2019
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

The disclosure relates to the technical field of building materials, and in particular, to lightweight aggregate ultra-high performance concrete (UHPC) and a preparation method thereof. The lightweight aggregate UHPC provided in the disclosure is prepared from the following components in parts by weight: cement 220-260 parts; silica fume 100-120 parts; expanded perlite powder 120-160 parts; expanded perlite 230-260 parts; polycarboxylate superplasticizer 15-20 parts; steel fiber 76-93 parts; and water 140-160 parts, where a maximum particle size of the expanded perlite powder is 0.075 mm; and a particle size range of the expanded perlite is 0.075-0.6 mm. The lightweight UHPC prepared according to the design of the disclosure has excellent density performance, and can satisfy requirements of concrete components, etc. in service in super-long-span bridges, super high-rise buildings, and complex marine environments for lightweight, ultra-high strength, and ultra-high durability of cement-based materials, and has a relatively high promotion value.

First claim

What is claimed is:

1. Lightweight aggregate ultra-high performance concrete (UHPC), prepared from the following components in parts by weight:

cement
220-400
parts;

silica fume
100-120
parts;

expanded perlite powder
5-150
parts;

expanded perlite
230-260
parts;

water
140-160
parts;

water-reducing agent
15-20
parts; and

steel fiber
76-93
parts; wherein

a particle size of the expanded perlite powder is less than 0.075 mm; and
a particle size range of the expanded perlite is 0.075-0.6 mm.

2. The lightweight aggregate UHPC according to claim 1 , wherein the cement is Portland cement, pozzolana cement, flyash cement, or slag cement, and an average particle size of the cement is 10.6 μm.

3. The lightweight aggregate UHPC according to claim 1 , wherein the water-reducing agent is polycarboxylate superplasticizer, and a water-reducing rate of the water-reducing agent exceeds 35%.

4. The lightweight aggregate UHPC according to claim 1 , wherein the steel fiber is a long-straight steel fiber, a diameter of the steel fiber is 0.1-0.3 mm, a length of the steel fiber is 6-15 mm, and tensile strength of the steel fiber is higher than 1600 MPa.

5. The lightweight aggregate UHPC according to claim 1 , wherein a design method for determining a formula of the lightweight aggregate UHPC comprises the following steps:
(1) designing a first mix proportion of base groups with a dense structure based on a close packing theory by using a Modified Andreasen and Andersen model;
(2) establishing functional relationships between amounts of the expanded perlite powder and the expanded perlite for replacement and ultra-high performance, namely, density and strength, according to a response surface methodology, and determining mixing amounts of the expanded perlite powder and the expanded perlite according to a performance requirement; and
(3) testing and verifying a second mix proportion designed according to the response surface methodology of (2), to obtain a mix proportion of the lightweight aggregate UHPC.

6. The lightweight aggregate UHPC according to claim 5 , wherein the expanded perlite powder is used to replace a part of the cement, and the expanded perlite is used to replace a part or all of quartz sand.

7. The lightweight aggregate UHPC according to claim 5 , wherein the formula of the lightweight aggregate UHPC in step (3) is as follows:
the lightweight aggregate UHPC is prepared from the following components in parts by weight: 244 parts of the cement, 112 parts of the silica fume, 147 parts of the expanded perlite powder, and 244 parts of the expanded perlite, 146 parts of the water, 18 parts of the water-reducing agent, and 93 parts of the steel fiber; or
the lightweight aggregate UHPC is prepared from the following components in parts by weight: 388 parts of the cement, 102 parts of the silica fume, 47 parts of the expanded perlite powder, and 223 parts of the expanded perlite, 137 parts of the water, 16 parts of the water-reducing agent, and 85 parts of the steel fiber.

8. A preparation method of the lightweight aggregate ultra-high performance concrete (UHPC) according to claim 1 , comprising the following steps:
(1) conducting first mixing on the cement, the silica fume, the expanded perlite powder, and the expanded perlite to obtain a mixture;
(2) conducting second mixing on the mixture, the water-reducing agent, and the water to obtain mixed slurry;
(3) conducting third mixing on the mixed slurry and the steel fiber to obtain a blank; and
(4) conducting heat curing on the blank to obtain the lightweight UHPC.

9. The preparation method according to claim 8 , wherein the heat curing comprises first-stage hot water curing and second-stage high-temperature dry curing that are conducted in sequence.

10. The preparation method according to claim 9 , wherein the first-stage hot water curing comprises pre-curing, a heating stage, a constant-temperature stage, and a cooling stage that are conducted in sequence, wherein
a pre-curing temperature is 20-40° C. and a pre-curing time is 12-36 h in the first-stage hot water curing;
a heating rate in the heating stage of the first-stage hot water curing is 0.1-1° C./min;
a constant-temperature stage temperature is 90-100° C. and a constant-temperature stage time is 6-8 h in the constant-temperature stage of the first-stage hot water curing; and
a cooling rate in the cooling stage of the first-stage hot water curing is 0.23-0.3° C./min; and
the second-stage high-temperature dry curing comprises a heating stage, a constant-temperature stage, and a cooling stage that are conducted in sequence, wherein
a heating rate in the heating stage of the second-stage high-temperature dry curing is 5-10° C./min;
a constant-temperature time in the constant-temperature stage of the second-stage high-temperature dry curing is 2-3 h; and
a cooling rate in the cooling stage of the second-stage high-temperature dry curing is 0.1-0.5° C./min.

11. The lightweight aggregate UHPC according to claim 2 , wherein a design method for determining a formula of the lightweight aggregate UHPC comprises the following steps:
(1) designing a first mix proportion of base groups with a dense structure based on a close packing theory by using a Modified Andreasen and Andersen model;
(2) establishing functional relationships between amounts of the expanded perlite powder and the expanded perlite for replacement and ultra-high performance, namely, density and strength, according to a response surface methodology, and determining mixing amounts of the expanded perlite powder and the expanded perlite according to a performance requirement; and
(3) testing and verifying a second mix proportion designed according to the response surface methodology of (2), to obtain a mix proportion of the lightweight aggregate UHPC.

12. The lightweight aggregate UHPC according to claim 3 , wherein a design method for determining a formula of the lightweight aggregate UHPC comprises the following steps:
(1) designing a first mix proportion of base groups with a dense structure based on a close packing theory by using a Modified Andreasen and Andersen model;
(2) establishing functional relationships between amounts of the expanded perlite powder and the expanded perlite for replacement and ultra-high performance, namely, density and strength, according to a response surface methodology, and determining mixing amounts of the expanded perlite powder and the expanded perlite according to a performance req

Assignees

• Univ Qingdao Technology

Inventors

• Hou Dongshuai
• Wang Xinpeng
• Li Mengmeng
• Geng Qihui
• Wang Pan
• Yin Bing
• Zhang Yue

Classifications

• C04B2111/40

  Porous or lightweight materials · CPC title

• C04B24/2641

  Polyacrylates; Polymethacrylates · CPC title

• C04B14/185

  expanded · CPC title

• C04B14/48

  Metal · CPC title

• C04B40/0263

  Hardening promoted by a rise in temperature (C04B40/024 takes precedence) · CPC title