Method for predicting and calculating of surface energy of aggregates

Patent metadata

Field	Value
Publication number	US-2023026109-A1
Application number	US-202217864139-A
Country	US
Kind code	A1
Filing date	Jul 13, 2022
Priority date	Jul 15, 2021
Publication date	Jan 26, 2023
Grant date	—

Abstract

A method for predicting and calculating aggregate surface energy is provided and includes steps: (1) raw aggregate screening and treatment; (2) surface texture index acquirement of a polished aggregate and an untreated raw aggregate; (3) powdered aggregate testing by a capillary rise method; (4) polished aggregate testing by a sessile drop method; (5) function relationship formula fitting; and (6) surface energy calculation of raw aggregate. The method not only considers the influence of aggregate's own composition on the surface energy, but also considers the influence of the polishing treatment on the aggregate surface texture, analyzes actual surface texture conditions of the aggregate, and significantly improves the test accuracy by combining the sessile drop method and the capillary rise method. Moreover, it can replace vapor adsorption method to test the surface energy of aggregate, which greatly reduces the test cost and operation difficulty.

First claim

What is claimed is:

1 . A method for predicting and calculating aggregate surface energy, comprising:
step (1), raw aggregate screening and treatment, comprising: screening a raw aggregate and dividing the screened raw aggregate into a polished aggregate been sequentially surface polished and pretreated, an untreated raw aggregate, and a powdered aggregate been ground in form of powder; step (2), surface texture index acquirement of the polished aggregate and the untreated raw aggregate, comprising: measuring surface textures of the untreated raw aggregate and the polished aggregate to obtain a surface texture index of the untreated raw aggregate and a surface texture index of the polished aggregate respectively; step (3), powdered aggregate testing by a capillary rise method, comprising: testing the powdered aggregate by the capillary rise method to obtain surface energy of the powdered aggregate without influence of surface texture; step (4), polished aggregate testing by a sessile drop method, comprising: testing a contact angle of the polished aggregate by the sessile drop method, and calculating surface energy of the polished aggregate; step (5), function relationship formula fitting, comprising: fitting based on the surface texture index of the polished aggregate, the surface energy of the powdered aggregate and the surface energy of the polished aggregate to obtain a function relationship formula of surface texture index and surface energy; and step (6), surface energy calculation of raw aggregate, comprising: substituting the surface texture index of the untreated raw aggregate into the function relationship formula of surface texture index and surface energy to thereby obtain surface energy of the raw aggregate considering influence of surface texture.

2 . The method according to claim 1 , wherein each of the untreated raw aggregate and the polished aggregate comprises aggregate samples with a particle size of 13.2˜16 millimeters (mm) after the screening;
wherein the polished aggregate has been surface polished by one or more selected from a group consisting of three surface polishing methods of cutting saw polishing, grinding wheel polishing and sandpaper polishing, a polishing time of each of the surface polishing methods is more than 30 seconds; and for each of the surface polishing methods, polishing degrees of the aggregate samples of the polished aggregate are the same.

3 . The method according to claim 1 , wherein a preparation of the powdered aggregate comprises:
weighing the screened raw aggregate with a particle size in a range of 2.36˜4.75 mm and then grinding the weighed raw aggregate, sieving the ground raw aggregate to obtain powders with particle sizes less than 0.075 mm to thereby obtain the powdered aggregate.

4 . The method according to claim 2 , wherein the measuring surface textures of the untreated raw aggregate and the polished aggregate to obtain a surface texture index of the untreated raw aggregate and a surface texture index of the polished aggregate respectively comprises:
fixing the aggregate samples of the untreated raw aggregate on an aggregate tray, collecting surface texture images of the aggregate samples of the untreated raw aggregate with an instrument of aggregate image measurement system (AIMS), and calculating the surface texture index of the untreated raw aggregate after averaging collection results; and fixing the aggregate samples of the polished aggregate on the aggregate tray, collecting surface texture images of polished surfaces of the aggregate samples of each of the surface polishing methods with the instrument of AIMS, and calculating the surface texture index of the polished aggregate of each of the surface polishing methods after averaging collection results.

5 . The method according to claim 4 , wherein the testing the powdered aggregate by the capillary rise method comprises:
saturating and curing the powdered aggregate with toluene, and calculating effective radii of capillary synthesis through the capillary rise method with 2-pentanone, formamide and n-hexane as first test reagents; testing by using a surface tension instrument under the first test reagents individually based on the capillary rise method, calculating a diffusion pressure under each of the first test reagents combined with the effective radius of capillary synthesis, and then calculating the surface energy of the powdered aggregate without the influence of surface texture according to Young-Dupre equation.

6 . The method according to claim 5 , wherein a calculation formula of the diffusion pressure is:

π

e
⁡
(

M
⁢
L

)

=

2
⁢
η

π
2

⁢

R
e
5

⁢

ρ
L
2

·

m
2

t

;

where π e(ML) represents the diffusion pressure, m represents a mass variation of the powdered aggregate, t represents time, ρL represents a density of the first test reagent, R e represents the effective radius of capillary synthesis, and η represents a diffusion pressure coefficient.

7 . The method according to claim 5 , wherein the testing a contact angle of the polished aggregate by using the sessile drop method comprises:
starting an optical contact angle measuring instrument and preheating, placing the polished aggregate in a test chamber of the optical contact angle measuring instrument, and making the polishing surface of each of the aggregate samples of the polished aggregate be horizontal and face towards a camera of the optical contact angle measuring instrument; adjusting reagent needles to preset positions, and releasing droplets of different second test reagents respectively; moving the test chamber to make each of the aggregate samples correspondingly receive the released droplet; and testing the contact angle between each of the aggregate samples and the received droplet within a preset test time.

8 . The method according to claim 7 , wherein the adjusting reagent needles to preset positions specifically comprises: pumping the different second test reagents into syringes respectively, moving positions of the reagent needles until a distance between each of the reagent needles and corresponding one of the aggregate samples is one droplet, and making the reagent needles and the aggregate samples appear in a capture image of the camera;
wherein the releasing droplets of different second test reagents respectively comprises: controlling pressures of the respective syringes to release the droplets with a same volume of the different second test reagents, and each of the released droplets is attac

Assignees

• Univ Wuhan Tech

Inventors

• Luo Rong
• Niu Longchang
• Liu Angang
• Chen Xuanjie
• Luo Jing
• Tu Chongzhi
• Wang Xiang
• Miao Qiang

Classifications

• G01N2013/0283

  methods of calculating surface tension · CPC title

• G01N13/02 Primary

  Investigating surface tension of liquids · CPC title

• G01N2013/0208

  by measuring contact angle · CPC title

• Y02W30/91

  Use of waste materials as fillers for mortars or concrete · CPC title

• G01N13/00 Primary

  Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects (scanning-probe techniques or apparatus G01Q) · CPC title