Aggregate Strength Tester

Product Introduction

thickAggregate Strength Testeran instruction manual:

1 Aggregate Strength TesterPurpose and Scope of Application

This method is to determine the performance of crushed stone or gravel that can withstand the crystallization pressure of sodium sulfate without significant damage or strength reduction after multiple soaking and drying cycles in a saturated sodium sulfate solution. It is a method for determining the strength (also known as stability) of stone materials.

2 Instruments and materials

2.1 Oven: capable of controlling the temperature at 105 ℃± 5 ℃.

2.2 Balance: Weigh 5kg with a sensitivity not exceeding 1g.

2.3 Standard sieve: Select according to Table T0314-1 based on the particle size of the sample.

Table 1 Quality of Samples for Each Particle Size Required for Robustness Test

Nominal particle size (mm)

2.36~4.75

4.75~9.5

9.5~19

19~37.5

37.5~63

63~75

Sample mass (g)

500

500

1000

1500

3000

5000

Note: The sample with a particle size range of 9.5mm to 19mm should contain 40% particles in the 9.5mm to 16mm particle size range and 60% particles in the 16mm to 19mm particle size range.

② In the sample with a particle size range of 19mm to 37.5mm, there should be 40% particles in the 19mm to 31.5mm particle size range and 60% particles in the 31.5mm to 37.5mm particle size range.

2.4 Container: Enamel basin or porcelain jar, with a capacity of not less than 50L.

2.5 Three legged mesh basket: The outer diameter of the mesh basket is 100mm, the height is 150mm, and it is made of copper mesh or stainless steel wire with a hole diameter not exceeding 2.36mm; When inspecting particles between 37.5mm and 75mm, a mesh basket with an outer diameter and height of 250mm should be used.

2.6 Reagents: Anhydrous sodium sulfate and 10 water crystalline sodium sulfate (for industrial use).

Instructions for using the coarse aggregate solidity test device:

3.1 Preparation of Sodium Sulfate Solution

Take a certain amount of distilled water (depending on the sample and container size), heat it to 30 ℃~50 ℃, add 300g~350g of anhydrous sodium sulfate (Na2SO4) or 700g~1000g of 10 water sodium sulfate (Na2SO4.10H2O) per 1000mL of distilled water, stir with a glass rod to dissolve and saturate, and then cool it to 20 ℃~25 ℃; At this temperature, let it stand for 48 hours, and its relative density should be maintained within the range of 1.151-1.174 (with a Baume degree of 18.9-21.4). During the experiment, there should be no crystals present at the bottom of the container.

3.2 Preparation of Samples

Classify the samples according to the specifications in Table T0314-1, wash them, dry them in an oven at 105 ℃± 5 ℃ for 4 hours, take them out and cool them to room temperature, and then weigh the mass mi of each particle size sample according to the specifications in Table T0314-1.

4 Experimental steps

4.1 Place the samples of different particle sizes into a three legged mesh basket and immerse them in a container containing sodium sulfate solution. The volume of the solution should not be less than 5 times the total volume of the sample, and the temperature should be maintained within the range of 20 ℃ to 25 ℃. When immersing the three legged mesh basket in the solution, it should be lifted up and down 25 times to eliminate bubbles in the sample, and then placed in the container; At this time, the bottom of the mesh screen should be about 30mm away from the bottom of the container (controlled by the height of the mesh basket feet), and the distance between the mesh baskets should not be less than 30mm. The surface of the sample should be at least 30mm below the liquid level.

After soaking for 20 hours, remove the mesh basket from the solution and bake it in an oven at 105 ℃± 5 ℃ for 4 hours, completing * test cycles. After the sample cools to 20 ℃~25 ℃, the second cycle begins. From the second cycle onwards, the soaking and baking time can both be 4 hours.

After completing five cycles, place the sample in clean water at 25 ° C to 30 ° C to wash the sodium sulfate, then dry it in an oven at 105 ° C ± 5 ° C until constant weight is reached. After cooling to room temperature, sieve the sample using the lower limit sieve hole of the sample size, and weigh the sieve residue m ′ i of each particle size after testing.

Note: Whether the sodium sulfate in the sample has been washed can be tested according to the following method:; Take a few milliliters of water for washing the sample and add a small amount of barium chloride (BaCl2) solution dropwise. If there is no white precipitate, it indicates that the sodium sulfate has been washed away.

4.4 For samples with a particle size greater than 19mm, the number of particles should be recorded before and after the test, and a visual inspection should be conducted to describe the cracks, peeling, edge and corner drops of the particles, as well as the number of particles they occupy, as a supplementary basis for analyzing their strength.

5. Calculation of experimental results:

Calculate the percentage of mass loss of each particle size in the sample according to equation (T0314-1).

Q i= mi－m′i/ mi

In the formula: Qi - the percentage of mass loss of each particle size fraction,%;

Mi - drying quality of each particle size sample before testing, g;

M ′ i - the drying quality of the residual particles in each particle size after being tested by the sodium sulfate solution method, g。

Calculate the percentage of total mass loss of the sample according to equation (T0314-2), accurate to 1%

Q=ΣαiQi/Σmi×100

In the formula: Q - percentage of total mass loss of the sample,%;

Mi - the mass percentage of each particle size in the sample,%;

Qi - Percentage of mass loss in each particle size fraction,%. Technical Specifications:

(1) Container: Double layer stainless steel heated constant temperature container.

(2) Coarse aggregate three legged mesh basket: The outer diameter of the mesh basket is 100mm, the height is 100mm, and the aperture is 2.36mm

The outer diameter of the mesh basket is 250mm, the height is 250mm, the aperture is 2.36mm, and it is made of stainless steel.

(3) Fine aggregate three legged mesh basket: The outer diameter of the mesh basket is 70mm, the height is 70mm, the aperture is 0.15mm, and it is made of stainless steel

(4) Power supply voltage: 220V

(5) Temperature should be maintained within the range of 20 ℃ to 25 ℃

(6) Number of lifts: 25 times

(7) This instrument can perform automatic heating, constant temperature, cycle times, and insulation time control for the above experiments, with full digital display function.