CN109696472B

CN109696472B - Method for measuring building gypsum setting time

Info

Publication number: CN109696472B
Application number: CN201710995130.7A
Authority: CN
Inventors: 王丽
Original assignee: Beijing New Building Material Group Co Ltd
Current assignee: Beijing New Building Material Group Co Ltd
Priority date: 2017-10-23
Filing date: 2017-10-23
Publication date: 2020-12-22
Anticipated expiration: 2037-10-23
Also published as: CN109696472A

Abstract

A method of determining a set time of building gypsum, the method comprising: adding a gypsum sample into water, and stirring to obtain uniform slurry; pouring the slurry into a testing barrel of an ultrasonic tester, and respectively contacting an ultrasonic transmitting probe and an ultrasonic receiving probe of the ultrasonic tester with the slurry on two sides of the testing barrel; starting an ultrasonic transmitter and a receiver of the ultrasonic tester, detecting the change condition of the speed or the energy of ultrasonic waves along with time in the gypsum setting process and drawing a curve; and reading the initial setting time and the final setting time of the gypsum according to a time variation curve of the velocity or the energy of the ultrasonic wave, wherein the time corresponding to the first inflection point on the time variation curve of the velocity or the energy of the ultrasonic wave is the initial setting time, and the time corresponding to the last inflection point is the final setting time. By adopting the method, the setting time of the building gypsum can be rapidly measured, errors caused by manual operation are avoided, and the test result is more accurate.

Description

Method for measuring building gypsum setting time

Technical Field

The present application relates to, but is not limited to, a method of determining the setting time of building gypsum.

Background

At present, the method for measuring the setting time of the building gypsum is mainly a Vicat instrument method, and reference is made to GB/T17669.4-1999 determination of physical properties of building gypsum powder. The testing steps are as follows:

1. water was weighed at standard consistency with water and poured into a mixing bowl. A200 g sample of gypsum was weighed and poured into water over 5 s. Stirring with a stirring rod for 30s to obtain uniform slurry, and pouring into a ring mold. The glass base plate was then raised approximately l0mm, shaken up and down 5 times, and the overflow was scraped off with a spatula and the slurry was made flush with the upper end of the ring mold. The ring mold filled with the slip was placed under the steel needle of the instrument with the glass base plate so that the tip of the needle was in contact with the surface of the slip and was spaced from the edge of the ring mold by more than l0 mm. The fixing screw on the rod is quickly loosened, and the needle is freely inserted into the slurry. Repeating every 30s, changing the insertion point every time, and wiping and straightening the needle.

2. And recording the time from the contact of the gypsum sample with water to the first contact of the steel needle with the glass bottom plate, namely the initial setting time of the gypsum sample. The time elapsed from the time the gypsum sample was contacted with water to the time the steel needle was first inserted into the slurry to a depth of no more than 1mm was recorded as the final set time of the gypsum sample. The average of the two measurements was taken as the initial set time and final set time of the gypsum sample to 1 min.

There are several problems with this current test method: 1. the testing process is complicated, and the operation steps are more and complicated; 2. the test result is greatly influenced by manual operation factors, and the test precision needs to be improved.

Disclosure of Invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

The application provides a new method for measuring the setting time of building gypsum by adopting ultrasonic waves.

Specifically, the present application provides a method of determining the setting time of building gypsum, the method comprising:

adding a gypsum sample into water, and stirring to obtain uniform slurry;

pouring the slurry into a testing barrel of an ultrasonic tester, and respectively contacting an ultrasonic transmitting probe and an ultrasonic receiving probe of the ultrasonic tester with the slurry on two sides of the testing barrel;

starting an ultrasonic transmitter and a receiver of the ultrasonic tester, detecting the change condition of the speed or the energy of ultrasonic waves along with time in the gypsum setting process and drawing a curve;

and reading the initial setting time and the final setting time of the gypsum according to a time variation curve of the velocity or the energy of the ultrasonic wave, wherein the time corresponding to the first inflection point on the time variation curve of the velocity or the energy of the ultrasonic wave is the initial setting time, and the time corresponding to the last inflection point is the final setting time.

In some embodiments, the time interval of the abscissa of the time-dependent rate or energy profile of the ultrasonic wave may be 2 to 60 seconds.

Optionally, the time interval of the abscissa of the velocity or energy profile of the ultrasonic wave with time is 2 seconds.

In some embodiments, the method of determining the setting time of building gypsum can further comprise placing the test bucket in an enclosed insulated box such that the test procedure is performed in an enclosed insulated environment. When the test is carried out in a closed and insulated environment, the energy curve of the ultrasonic wave measured with time is more accurate due to no heat loss, and the final coagulation time is more accurate.

In some embodiments, after pouring the slurry into the test tub of the ultrasonic tester, the method for determining the setting time of the building gypsum may further comprise lifting the test tub by about 10mm, shaking up and down 5 times, and scraping off the overflowed slurry.

In some embodiments, after the slurry is poured into the test bucket of an ultrasonic tester, the surface of the slurry may be flush with the upper end of the test bucket.

In some embodiments, the test may be performed at 0-40 ℃.

Alternatively, the test is performed at 20 ℃.

In some embodiments, the step of adding the gypsum sample to water and agitating to obtain a uniform slurry may comprise: weighing water according to the water quantity of the standard consistency, adding a certain quantity of the gypsum sample into the water within a certain time, and stirring to obtain uniform slurry.

In some embodiments, the amount of the gypsum sample may be such that the slurry is able to fill the test bucket, alternatively 300 g.

In some embodiments, the certain time may be 1 to 10 seconds.

Optionally, the certain time is 5 seconds.

In some embodiments, the time of stirring may be 10 to 40 seconds.

Optionally, the time of stirring is 30 seconds.

The application provides a method and steps for testing the setting time of building gypsum by utilizing ultrasonic waves, and solves the problems that the traditional test process for testing the setting time of building gypsum is complicated, and the test result is greatly influenced by manual operation. By adopting the method for measuring the setting time of the building gypsum, the setting time of the building gypsum can be quickly measured, and the test result is accurate.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the claimed subject matter and are incorporated in and constitute a part of this specification, illustrate embodiments of the subject matter and together with the description serve to explain the principles of the subject matter and not to limit the subject matter.

FIG. 1 is a graph showing the change of the velocity of ultrasonic waves with time measured in example 1.

Detailed Description

To make the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

Example 1

1) Water was weighed at standard consistency with water and poured into a mixing bowl. Weighing 300g desulfurized gypsum clinker sample (desulfurized gypsum comes from iron ridge power plant, clinker is calcined by iron ridge division company of North New group building materials Co., Ltd.), pouring into water within 5s, and stirring with a mixing rod for 30s to obtain uniform slurry.

2) The slurry was poured into a test bucket of an ultrasonic tester (produced by UltraTest GmbH, germany, IP-8 ultrasonic measurement system), the test bucket was lifted by about l0mm, shaken up and down 5 times, and the overflowed slurry was scraped off with a scraper so that the surface of the slurry was flush with the upper end of the test bucket.

3) An ultrasonic transmitting probe and a receiving probe of the ultrasonic tester are respectively contacted with the slurry on two opposite sides of the testing barrel, an ultrasonic transmitter and a receiver of the ultrasonic tester are started, the change condition of the speed of ultrasonic waves along with time in the gypsum setting process is detected and drawn into a curve, and see figure 1.

4) And reading the initial setting time and the final setting time of the gypsum according to the time variation curve of the velocity of the ultrasonic wave, wherein the time corresponding to the first inflection point on the time variation curve of the velocity or the energy of the ultrasonic wave is the initial setting time, and the time corresponding to the last inflection point is the final setting time.

The denser the material, the faster the ultrasonic wave will propagate within it. The bubbles in the gypsum slurry caused a difference in the initial wave velocity during the first few seconds of the test (the longitudinal wave was air, which was decisive for the ultrasonic wave propagation velocity when it propagated in a bubble-containing slurry, and water, which was decisive when it propagated in a bubble-free cement slurry). Further, since the formation of crystal nuclei occurs at the initial stage of setting of the slurry, the state of the slurry is unstable, and a pseudo-set state may occur, the measured curve fluctuates greatly from the beginning, and the curve should be ignored when the setting time of the gypsum is read.

As can be seen from FIG. 1, the time corresponding to the first inflection point and the time corresponding to the last inflection point on the time-dependent change curve of the velocity of the ultrasonic waves is 1.93min, so that the initial setting time and the final setting time of the gypsum are 1.93min and 3.13min, respectively.

Although the embodiments disclosed in the present application are described above, the descriptions are only for the convenience of understanding the present application, and are not intended to limit the present application. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.

Claims

1. A method of determining a set time of building gypsum, the method comprising:

adding a gypsum sample into water, and stirring to obtain uniform slurry;

starting an ultrasonic transmitter and a receiver of an ultrasonic tester, detecting the change condition of the speed of ultrasonic waves along with time in the gypsum setting process and drawing a curve;

and reading the initial setting time and the final setting time of the gypsum according to a time variation curve of the velocity of the ultrasonic wave, wherein the time corresponding to the first inflection point on the time variation curve of the velocity of the ultrasonic wave is the initial setting time, and the time corresponding to the last inflection point is the final setting time.

2. The method according to claim 1, wherein the time interval of the abscissa of the time-dependent velocity profile of the ultrasonic wave is 2 to 60 seconds.

3. The method according to claim 2, wherein the time interval of the abscissa of the time-dependent velocity profile of the ultrasonic waves is 2 seconds.

4. The method of claim 1, further comprising placing the test bucket in an enclosed insulated box such that the testing process is performed in an enclosed insulated environment.

5. The method of claim 1, after pouring the slurry into a test barrel of an ultrasonic tester, further comprising lifting the test barrel by about 10mm, shaking up and down 5 times, and scraping off overflow slurry.

6. The method of claim 1, wherein the surface of the slurry is flush with the upper end of a test bucket of an ultrasonic tester after the slurry is poured into the test bucket.

7. The method of any one of claims 1-6, wherein the testing is performed at 0-40 ℃.

8. The method of claim 7, wherein the testing is performed at 20 ℃.

9. The method of any of claims 1-6, wherein the step of adding the gypsum sample to water and stirring to obtain a uniform slurry comprises: weighing water according to the water quantity of the standard consistency, adding a certain quantity of the gypsum sample into the water within a certain time, and stirring to obtain uniform slurry.

10. The method of claim 9, wherein the amount of the gypsum sample is such that the slurry can fill the test bucket.

11. The method of claim 9, wherein the certain time is 1-10 seconds.

12. The method of claim 11, wherein the certain time is 5 seconds.

13. The method of claim 9, wherein the stirring time is 10-40 seconds.

14. The method of claim 13, wherein the stirring time is 30 seconds.