The Slurry Seal Cohesion Tester is used to determine the cohesion strength and curing characteristics of slurry seal mixtures and emulsified asphalt mixtures. It is an essential laboratory instrument for evaluating mixture workability, early strength development, and construction performance in slurry surfacing and micro-surfacing applications.

Slurry Seal Cohesion Tester

Model:TD754-1

I. Product Introduction

The TD754-1 Slurry Seal Cohesion Tester is a specialized laboratory testing instrument developed by Hebei Tianqixingzi Inspection Equipment Co., Ltd. in accordance with JTG 3410-2025(T0754-2025 Slurry Mixture Cohesion Test).The instrument is primarily used to evaluate the cohesion strength between emulsified asphalt and aggregates in slurry seal mixtures. It is an important testing device for determining the curing characteristics and estimating the appropriate traffic opening time after slurry seal construction.

Reference or Applicable Standards:EN 12274-4, ISSA TB139, ASTM D3910, ASTM D6372, EN 12273.

II. Instrument and Material Technical Requirements:

1. Technical Parameters:

Pressure Head Size: Diameter: 28.6 mm ± 0.1 mm; Thickness: 28 mm ± 1.0 mm.

Rubber Gasket Diameter: 28.6 mm ± 0.1 mm.

Rubber Gasket Thickness: 64 mm ± 0.1 mm.

Rubber Hardness: HRC60 ± HRC20.

Pressure Head Height and Falling Speed: 50–70 mm; Falling speed ≤ 8 cm/s.

Indenter Head Pressure: 128.5N±1.0N

Air Pressure Gauge Range: 0–700 kPa, Graduation value: 10 kPa.

2. Special Torque Wrench for Testing

Technical Parameters:

Torque gauge range: ≤ 3.5 N·m

3. Test Mold

Dimensions:

Φ60 mm × 6 mm

4. Test Mold

Dimensions:

Φ60 mm × 10 mm

5. TDMB-1 Stopwatch

6. Other Testing Accessories

No. 220 sandpaper, Oil felt pad: 150 mm × 150 mm, Mixing cup, Mixing spatula, Other related testing accessories

III.Test Procedure

1. Calibration of the Cohesion Tester

Use No. 220 coarse sandpaper to conduct the “cohesion test.”For 10 consecutive tests, the difference between the maximum and minimum torque wrench readings shall be less than 0.3 N·m, and the standard deviation of the measured results shall not exceed 0.2 N·m.

2. Specimen Preparation

2.1Prepare materials according to the mixture proportion determined by the mixing test. Normally, the test is based on 300 g of dry aggregate.

2.2Pour the aggregate and filler into the mixing cup and mix thoroughly. Then add water and additives into the cup and mix evenly. After that, add emulsified asphalt or modified emulsified asphalt and mix for no more than 30 s ± 2 s.

2.3Pour the slurry mixture into the pre-wetted test mold with an oil felt pad placed underneath. Strike off the surface evenly, remove the mold, and start timing immediately. The specimen shall be cured in an environment at 25°C ± 2°C.

3. Test Procedure

3.1 Test Procedure After 30 Minutes of Curing

Place the specimen on the testing platform of the cohesion tester.

Press the pneumatic pressure head onto the specimen. At this time, the reading of the air pressure gauge shall be maintained at 200 kPa.

Keep the pressure constant, reset the torque wrench dial to zero, and attach it to the upper end of the cylinder rod. Rotate it smoothly, firmly, and horizontally through an angle of 90°–120° within 0.7–1.0 s, then record the torque wrench reading.

Evaluate the specimen failure condition according to the following four categories:

Fully Cohesive:

The specimen shows no cracks or damage, and no aggregate loss occurs. The pressure head slips on the specimen surface, and the asphalt film on the surface may be worn off, leaving a circular mark.

(Equivalent cohesion value: 2.6 N·m)

Moderately Cohesive:

No visible cracks appear on the specimen surface, but aggregates under the pressure head may be displaced or pulled out.

(Equivalent cohesion value: 2.3 N·m)

Initially Cohesive:

One crack appears on the specimen surface.

(Equivalent cohesion value: 2.0 N·m)

Not Cohesive:

Multiple cracks appear, or the entire specimen is severely damaged or disintegrated.

(Cohesion value lower than 1.2 N·m)

After the test, raise the pressure head and clean it before the next test.

3.2 The testing procedure for specimens cured for 60 minutes shall be the same as described in Section 3.1.

4. Test Report

1.Two parallel tests shall be conducted on the same specimen. When the difference between the two measured values meets the allowable error requirements for repeatability tests, the average value shall be taken as the test result, accurate to 0.1 N·m.

2.The test report shall include:

Mixture proportion of the slurry mixture;

Test temperature, humidity, and other environmental conditions;

Cohesion values of the mixture after 30 minutes and 60 minutes of curing;

Description of the failure condition of the 60-minute cohesion test specimen after testing.