Essais sur les sols Laboratory Testing

Water content Test ( Moisture Content ) This test consists of determining the mass of the wet soil specimen and the dry soil specimen in an oven overnight ( 12 to 16 h ) at a temperature of 110 C 5 C

The mass of the soil specimen to use depends on the maximum particle sizeSpecific gravity test Dimensionless parameter that relates the density of the soil particles to the density of water Knowing the Ms we can determine Vs by using a pycnometer and add water and use a vaccum pump to pump air from the voids

Sieve Analysis ( Tamisage )

Key element in the classification system of a soil. The distribution of particles larger than 0.075 mm Sieve No 200 is determined by sieving while a sedimentation process (Hydrometer test) is used for the distribution of particles smaller than 0.075 mm.A sieve analysis is performed on dry soil particles that are larger than the No. 200 U.S. standard sieve (i.e., sand size, gravel size, and cobble size particles).The laboratory test procedures for performing a sieve analysis are presented in ASTM D 422-02(2004), Standard Test Method for Particle-Size Analysis of Soils.

No 200 Sieve is the separator between sand and silt

The basic steps are as follows: 1. Determining the initial dry mass of the soil (Ms).2. The soil is washed on the No. 200 sieve in orderTo remove all the fines (i.e., silt and clay size particles).3. Oven dry the soil retained on the No. 200 sieve4. Dry soil is poured into the sieves 5. Shaking can be whether manual or mechanical 6. After shaking, a balance is used to determine the mass of soil retained on each sieve 7. also known as the percent passing, is then calculated8. Plot the graph representing the percentage passing against the sieve size Semi-logarithmic scale

Hydrometer test ( Fine grained soils )

A sedimentation process is used to determine the particle distribution for fines (i.e., silt and clay sizeParticles finer than the No. 200 sieve.The hydrometer test is based on Stokes law, which relates the diameter of a single sphere to the time required for the sphere to fall a certain distance in a liquid of known viscosity

The basic steps are as follows:

1. 60 g of fine grained soil 2. Add 125 ml of sodium break down the cohesion between particles3. Calibrate the hydrometer 0 correction factor 4. Mix the solution 5. Add it to a jar 6. Add the hydrometer and take reading at: 1,2,5,15,30,60,250 and 1440 min7. Take the temperature reading

If the amount of fines is less than 5 percent (i.e., percent passing No. 200 sieve is less than 5 percent),Typically a hydrometer test is not performed, usually if the percent passing the No. 200 sieve isGreater than 15 percent, a hydrometer test could be performedAtterberg limit tests