T0591-2020Test method for water retention of cement mortar

1Purpose, scope of application, and reference standards

This method specifies the test method for the water retention of cement mortar

This method is applicable for determining cement mortar and other materials measured using this method.

Reference standards:

Chemical Analysis Filter Paper(GBT1914)

Method for Mixing and Consistency Testing of Cement Mortar(T0587)

2Instruments and materials

21Metal or hard plastic ring trial mold:inner diameter100mmInternal height25mm

22Sealed sampling container:Should be clean and dry.

232kgThe heavy object.

24Metal filter screen:grid size45um,rotundity,diameter100mm+1mm.

25Medical cotton yarn:Size is11m×10m,Cotton yarn with sparse yarn and thin thickness should be selected

26Ultra white filter paper:Should comply with the current "Chemical Analysis Filter Paper"(GBT1914)Requirements for Medium Speed Qualitative Filter Paper,straight

path110mm,density200gm2

27Two square or circular impermeable sheets of metal or glass,The side length or diameter should be greater than110mm

28balance:The range is200g,Sensitivity is0.1g;The range is2000g,Sensitivity is1ga

Oven.

3Experimental steps

Measurement steps for mortar moisture content test100g10gSample of mortar mixture,recorded asm,Placed in a dry and weighed dish,In105℃sDry in a constant weight oven at ℃,Weigh the quality asm2

32Test steps for water retention rate of mortar

(1)Weigh the bottom impermeable sheet and dry test mold massm2and15Quality of medium speed qualitative filter paperm4

(2)Load the mortar mixture into the test mold at once,And use a spatula to tamp it several times,When the filling mortar is slightly higher than the edge of the test mold,Use a spatula to45Scrape off excess mortar on the surface of the trial mold at once,Then use a spatula to scrape the mortar flat in the opposite direction on the surface of the test mold at a relatively flat angle

(3)Remove the mortar from the edge of the trial mold,Weigh the total mass of the trial mold, bottom impermeable sheet, and mortarm

(4)Cover the mortar surface with two pieces of medical cotton yarn,Place it on the surface of the cotton yarn again15Filter paper,Cover the surface of the filter paper with a bottom impermeable sheet,with2kgThe heavy object is pressing down on the impermeable sheet

(5)still2minRemove heavy objects and impermeable sheets afterwards,Remove the filter paper(Excluding cotton yarn,Quickly weigh the quality of filter paperm

4Result Calculation

5Test Report

The test report should include the following contents:

(1)Name and execution standards of the required testing items;

(2)Variety, specifications, and place of origin of raw materials

(3)Name, model and number of the instrument and equipment

(4)Environmental temperature and humidity:

(5)water retention rate

(6)Other content to be explained.

provisions explanation

This method refers to the "Standard Test Method for Basic Performance of Building Mortar"(GT70-200)preparation,The water retention of mortar is used to determine the mixing of mortar

The stability of the internal components of the complex during transportation and parking.