Information on the most widely used ASTM standards within the materials testing industry
Model: UTR1072-SD1, ASTM D4644
Rock Slake Durability Index Tester designed base standard ASTM D4644, mainly simulates the working conditions of rocks undergoing repeated wetting and drying cycles, water erosion, and weathering in a natural environment, quantitatively measures the rock disintegration resistance index, and evaluates the rock's water stability, weathering resistance, and long-term durability. It is a specialized indoor testing device in the field of geotechnical engineering.
General Introduction
Rock Slake Durability Index Tester (also known as the Rock Disintegration Test Instrument) is a specialized indoor testing device in the field of geotechnical engineering. It mainly simulates the working conditions of rocks undergoing repeated wetting and drying cycles, water erosion, and weathering in a natural environment, quantitatively measures the rock disintegration resistance index, and evaluates the rock's water stability, weathering resistance, and long-term durability.
The equipment is overall composed of four core parts: a drive system, a standard cylindrical sieve drum, a constant temperature water tank, and a control unit. The machine has a stable structure, precise rotation speed, and easy operation. It comes in single-drum, double-drum, and multi-drum models, capable of conducting multiple sample parallel tests simultaneously. This instrument is a necessary device for testing collapsible rocks such as argillaceous rocks, shale, weathered rock, and soft rock. It is widely used in engineering surveys, transportation, water conservancy, mining, geological testing, and scientific research and teaching, providing core test data for rock mass classification, engineering stability assessment, and building material selection. It is also a standardized instrument in major testing laboratories.
Key Features
Place rock test blocks of specified quality and size into a standard sieve cylinder, immerse the cylinder in constant-temperature water, and have the equipment rotate the cylinder at a constant speed; the test blocks continuously tumble, rub, and become water-saturated in the water, causing weak particles to gradually fall off and disintegrate, thereby simulating the weathering process of natural wetting-drying cycles and water flow erosion. After completing the standard wet-dry cycle, dry and weigh the remaining samples. By calculating the mass ratio of the sample before and after the cycle, the secondary cycle disintegration resistance index Id2 is obtained. The higher the index value, the better the rock's resistance to disintegration, weathering, and water stability; the lower the index, the more easily the rock softens and disintegrates upon contact with water, indicating higher engineering risk and the need for targeted reinforcement and protection measures.
Many types of rocks, especially those with high clay content, are prone to disintegration and exfoliation under repeated short-term wetting and drying. This experiment simulates the natural wetting and drying processes of rocks by artificial mechanical means. After two standard cycles (for harder rocks, three or more standard cycles may be applied), the ability of the rock specimens to resist softening and disintegration is referred to as the rock's slake durability.
Determination of Rock Disintegration Resistance Index
For rocks that easily disintegrate upon contact with water, such as mudstone, shale, siltstone, weathered rock, and soft coal series rocks, determine the disintegration resistance index under standard wet-dry cycles. This quantifies the rock's resistance to water erosion and disintegration and is a core indicator for evaluating rock water stability.
Determination of Rock Weathering Degree
Differentiate between fresh rock, weakly weathered, strongly weathered, and fully weathered rock masses, providing quantitative evidence for the classification of engineering rock mass weathering levels, and guiding the risk assessment of slopes, foundation pits, and surrounding rock.
Engineering Rock Mass Quality Classification
In coordination with rock mass evaluation systems such as RMR and Q-system, perform rock mass quality classification based on the disintegration resistance index to provide parameters for the site selection and design of tunnels, roadbeds, dam foundations, and other engineering projects.
Water-Related Engineering Risk Assessment
Predict the deterioration patterns of rocks under alternating wet and dry conditions caused by long-term rainfall, groundwater soaking, and water level fluctuations, and assess the geological disaster risks such as slope landslides, surrounding rock collapses, and foundation instability.
ASTM D4644 Standard Test Method for Slake Durability of Shales and Other Similar Weak Rocks
Main parameters
| Main motor power | 90W |
| Rotation speed | 20 rpm |
| Sieve drum | φ140*100mm |
| Standard sieve aperture | 2mm |
| Water tank capacity | 150*150*120mm |
| Sample specifications | 40–60g each, total 10 pieces |
| Specimen shape | roughly spherical, without edge |
| Dimensions | 1070*500*1200mm |
| Weight | 100kg |
Frequently Asked Questions
Standard Test Operating Procedure
1 Pre-test Preparation
1.1 Sample Preparation
Select representative rock samples and process them into rounded rock blocks of 40~60g each, with no fewer than 10 blocks per group. Remove loose debris and sharp edges from the surface, and record information such as lithology, origin, and degree of weathering.
1.2 Equipment and Instrument Inspection
Check that the sieve cylinder mesh is free of damage and that the shaft rotates smoothly; ensure the water tank is clean and free of debris, connect the power supply, and adjust the temperature control system to (20±2℃); preheat the oven to 105~110℃, and prepare a desiccator and a high-precision balance.
1.3 Initial Drying and Weighing
Place 10 samples into a clean sieve cylinder and put it into the oven. Dry continuously for 24 hours until constant weight is achieved; after removing, cool in the desiccator to room temperature, then weigh the total mass of the cylinder and specimens (A), and at the same time weigh the empty cylinder (D), with readings accurate to 0.01g.
2. First Dry-Wet Cycle Test
Fill the water tank with tertiary distilled water, keeping the water level 20mm below the rotation axis of the sieve cylinder, and ensure the water temperature meets the standard.
Mount the sieve cylinder containing the samples steadily on the shaft, making sure it rotates without sticking or collision.
Start the equipment; the sieve cylinder rotates at 20 r/min for 10 minutes to complete the first immersion, flushing, and disintegration process, after which the equipment stops automatically.
Remove the sieve cylinder, drain surface water, then place it in the 105~110℃ oven to dry for 24 hours. After cooling to room temperature, weigh the total mass of the remaining specimens in the cylinder (B) and record.
3. Second Dry-Wet Cycle Test
Repeat the above immersion, rotation, drying, and weighing procedure for the second cycle, and measure and record the total mass of the remaining specimens in the sieve cylinder (C) (the core of the national standard is the second cycle test).
4. Test Conclusion and Data Processing
Pour out the remaining specimens from the sieve cylinder, clean the disintegrated debris from the sieve cylinder and water tank, wash the equipment, and turn off the power.
Calculate the secondary cycle disintegration resistance index Id2 according to the formula, and describe the morphology of the remaining specimens, water turbidity, and sediment characteristics.
Organize the test data, sample information, and environmental parameters, and fill in the test report according to the standard format.
If in-depth research is needed, continue with the 3rd to 5th cycles to compare the disintegration patterns of the rock under multiple cycles.
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