Methods of test for stabilized soils, Part 4: Wetting and drying, and freezing and thawing tests for compacted soil-cement mixtures
1968 Edition

The preparation involves promptly compacting the freshly mixed soil-cement into the mould with the collar attached, typically in two layers. After compacting the initial layer, the surface should be scarified by creating grooves 3 mm wide and deep, spaced 6 mm apart at right angles to promote bonding with the subsequent layer. At least four specimens are prepared: two for routine testing and two for research or special soil analyses. Additionally, a representative soil-cement sample of no less than 100 grams is collected during compaction to determine moisture content. After compaction, specimens are trimmed according to specified dimensions to ensure uniformity.

Both wetting-drying and freezing-thawing tests require the specimens to undergo 12 complete cycles. Each cycle spans 48 hours, combining the respective wetting and drying or freezing and thawing phases. Weight measurements are generally taken after each cycle during research activities. Testing may be discontinued earlier if specimen degradation results in unreliable measurements. If testing interruptions occur, specimens should be stored in an oven to prevent moisture loss.

Key equipment includes a freezing cabinet capable of maintaining temperatures at or below -23°C for 24 hours, a moist chamber or covered container maintained at 25 to 30°C with 100% relative humidity for 23 hours, and absorbent pads approximately 5 mm thick placed between specimens and their carriers to facilitate capillary water absorption during thawing. Additionally, a supply of potable water is required to keep the absorbent pads moist. A sharp pointed tool is recommended for carefully removing scale formation from specimen surfaces after multiple cycles.

Measurements focus on specimens numbered 1 and 2 for volume and moisture changes. After a curing period of seven days and after each wetting-drying cycle, the height and diameter of specimens are measured at consistent points with an accuracy of ±0.2 mm. The specimen volume is calculated assuming a cylindrical shape using the formula V = π × (d/2)^2 × h. Moisture content is determined gravimetrically by weighing specimens to find the difference between wet and dry weights, expressed as a percentage. These systematic measurements enable precise monitoring of specimen degradation throughout the testing cycles.

Durability is evaluated by monitoring soil-cement loss through weight or volume changes after repeated wetting-drying or freezing-thawing cycles. Specimens numbered 1 and 2 are observed for volume and moisture variations, and testing may cease prematurely if loss impairs measurement accuracy. Specimens 3 and 4 are specifically used to determine moisture content and dry density to quantify soil-cement loss. Key indicators of durability include the extent of soil-cement material loss, moisture content fluctuations, and volumetric changes such as swelling or shrinkage.