Method for testing surface energy of aggregate based on static drop method

Patent metadata

Field	Value
Publication number	US-11982608-B2
Application number	US-202217826171-A
Country	US
Kind code	B2
Filing date	May 27, 2022
Priority date	Jul 15, 2021
Publication date	May 14, 2024
Grant date	May 14, 2024

Abstract

Disclosed is a method for measuring surface energy of aggregates based on static drop method, comprising (1) aggregates grinding and pretreatment; (2) obtaining the surface texture index; (3) calculating the surface energy based on static drop method experiment; (4) fitting to obtain a functional relationship between the surface texture index and surface energy; (5) calculating the surface energy of the original aggregate. The method considers the influence of the grinding process on the surface texture of the aggregates when measuring the surface energy of the aggregates, which significantly improves the accuracy of the static drop method test. The static drop method can be used to replace the vapor adsorption method to test the surface energy of aggregate, and the low-cost optical contact angle instrument can replace the expensive magnetic suspension weight balance system to test the surface energy of aggregate, which greatly reduces the test cost.

First claim

What is claimed is:

1. A method for testing surface energy of aggregate based on static drop method, comprising the following steps:
(1) aggregates grinding and pretreatment: dividing the original aggregates into two groups, one group is subjected to surface grinding and pretreatment and recorded as polished aggregate, and the other group is not treated and recorded as original aggregate;
(2) obtaining the surface texture index: testing the surface texture of the original aggregate and the polished aggregate to obtain the surface texture index of the original aggregate and the surface texture index of the polished aggregate, respectively;
wherein testing the surface texture of the original aggregate and the polished aggregate comprises:
fixing aggregate sample of the original aggregate on aggregate tray of AIMS system, using the AIMS system to test the surface texture of the aggregate sample of the original aggregate, and calculating the surface texture index of the original aggregate after averaging test results;
fixing aggregate samples of the polished aggregate on the aggregate tray, and photograph polished surfaces of the aggregate samples of the polished aggregate: after taking the average of shooting results, calculating the surface texture index of the polished aggregate:

(3) calculating the surface energy based on static drop method experiment: using static drop method to test contact angle of the polished aggregate, and calculating the surface energy of the polished aggregate;
wherein on a surface of the aggregate sample of the polished aggregate, an intersection of a droplet received by the surface and a projection of the received droplet is defined as a baseline, an angle between a tangent at the intersection of the droplet and the baseline is defined as the contact angle;
wherein calculating the surface energy of the polished aggregate comprises:
bringing the contact angle into the Young-Dupre equation; and
obtaining the surface energy parameters by using programming solution;

wherein the surface energy of the polished aggregate is calculated as:
2(√{square root over (γ S LW γ L LW )}+√{square root over (γ S + γ L − )}+√{square root over (γ S − γ L + )})=γ L (1+cosθ);

wherein the surface energy parameters include γ S LW , γ L LW , γ S + , γ S − , γ L + , γ L − , and γ L , among, γ S LW is the non-polar component of the surface energy of solid material, γ L LW is the non-polar component of the surface energy of liquid material, γ S + is the polar acid component of the surface energy of solid material, γ S − is the polar alkali component of the surface energy of solid material, γ L + is the polar acid component of the surface energy of liquid material, γ L − is the polar alkali component of the surface energy of the liquid material, γ L is the surface tension of the liquid with a unit of erg/cm 2 , θ is the contact angle between the solid-liquid-gas phase;
(4) fitting to obtain a functional relationship between the surface texture index and surface energy: performing fitting based on the surface texture index of the polished aggregate and the surface energy of the polished aggregate, and obtaining a functional relationship between the surface texture index of the polished aggregate and the surface energy of the polished aggregate;
(5) calculating the surface energy of the original aggregate: bringing the surface texture index of the original aggregate into the functional relationship between the surface texture index of the polished aggregate and the surface energy of the polished aggregate to obtain the surface energy of the original aggregate.

2. The method for testing surface energy of aggregate based on static drop method according to claim 1 , wherein the original aggregate and the polished aggregate both contain several aggregate samples with the same initial particle size;
the surface grinding method of the grinding aggregate is any one, two, or three of cutting saw grinding, grinding wheel grinding and sandpaper grinding, the grinding time of each surface grinding method is more than 30s, and the grinding degree of each aggregate sample in the polished aggregate is the same.

3. The method for testing surface energy of aggregate based on static drop method according to claim 2 , wherein the specific steps of the pretreatment are: after the surface of the polished aggregate is polished, rinsing it with distilled water until no sediment is attached to the surface, and drying the cleaned aggregate sample at 110-120° C.

4. The method for testing surface energy of aggregate based on static drop method according to claim 1 , wherein the specific steps of using static drop method to test contact angle of the polished aggregate are:
starting an optical contact angle meter and preheating, fixing the polished aggregate in the test chamber uniformly, and setting the grinding surface of each aggregate sample in the polished aggregate to face the camera of the optical contact angle meter;
adjusting the reagent needle to a preset position and releasing the droplets of different test reagents;
moving the test chamber so that each aggregate sample corresponds to receive one of the released droplets;
testing the contact angle between each aggregate sample and the received droplet for a preset test time.

5. The method for testing surface energy of aggregate based on static drop method according to claim 4 , wherein the specific steps for adjusting the reagent needle to the preset position are:
drawing the test reagent into a needle tube, moving the position of the reagent needle until a distance of a drop is maintained between the needle and the aggregate sample, and both the needle and the aggregate sample appear in the camera picture;
the specific steps of releasing droplets of different test reagents are:
controlling the pressure of the needle tube, so that different test reagents release droplets of the same volume, and the released droplets are attached to the tip of the needle, wherein the different test reagents included distilled water, formamide, and ethylene glycol, and each needle released a droplet of one test reagent.

6. The method for testing surface energy of aggregate based on static drop method according to claim 5 , wherein the specific steps for testing the contact angle between each aggregate sample and the received droplet within the preset test time are as follows:
on the surface of the aggregate sample, the intersection of the received droplet and its projection is set as the baseline, and using an optical contact angle meter to measure the angle between the tangent at the intersection of the droplet profile and the baseline, which is recorded as contact angle, obtaining the contact angles between the polished aggregate and different test reagents.

7. The method for testing surface energy of aggregate based on static drop method according to claim 6 , when using distilled water as the test reagent, the preset test time of the contact angle is 10-30s;
when using formamide or ethylene glycol as the test reagent, the preset test time of the contact angle is greater than 20s.

8. The method for testing surface energy of aggregate based on static drop method according to claim 1 , wherein the specific steps for obtaining the functional relationship between the surface texture index and the surface energy by fitting are:
fitting the surface energy of the polished aggregate and the surface texture index of the polished aggregate exponentially to obtain a functional relationship between the surface texture index and the surface energy, the specific functional relationship is:
γ= Ae Kx

where γ is aggregate surface energy considering the influence of surface textu

Assignees

• Univ Wuhan Tech

Inventors

• Luo Rong
• Luo Jing
• Tu Chongzhi
• Huang Tingting
• Wang Xiang
• Niu Longchang
• Miao Qiang

Classifications

• G01N13/02 Primary

  Investigating surface tension of liquids · CPC title

• G01N2013/0208

  by measuring contact angle · 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

• G01N33/42

  Road-making materials (G01N33/38 takes precedence) · CPC title