AS 1289.4.3.1 pdf download

AS 1289.4.3.1 pdf download.Methods of testing soils for engineering purposes
4 Apparatus
The following apparatus are required: (a) pH meter, covering at least the range pH 3.0 to pH 13.0, fitted with a scale that is readable and accurate to 0.05 pH units. NOTE 1 Soils with high pH values, such as stabilized soils and naturally occurring soils with a pH in excess of 10, should use an electrode reading to pH 13.0 as other electrodes would be adversely affected. NOTE2 The pH meter manufacturer’s instructions should be followed. . (b) Balance of at least 100 g capacity, with a limit of performance not greater than士0.05 g. [c] 100 mL glass beakers, with cover glasses and stirring rods. [d) Wash-bottle, preferably plastic, containing distilled water. [e) 2.36 mm sieve, conforming to ISO 3310-2. [f) Thermometer, readable and accurate to 1 °C NOTE3 This thermometer may be incorporated into the pH meter.
5 Reagents
The following reagents of analytical reagent (AR) grade are required: a Buffer solutions一pH 4.0, pH 9.2 and other pH levels within 2 pH units of the soil being measured as required. (b) Potassium chloride – Saturated solution, for maintenance of calomel electrode. [c) Distilled water一pH of between 6.75 and 7.25, stored in a sealed container.
6 Procedure
Tests shall be performed within the temperature range of 15 °C to 25 °C. The procedure shall be as follows: (a) Obtain a sample which has been prepared in accordance with the procedure for the preparation of disturbed samples for testing specified in AS 1289.1.1. Remove all particles by sieving over the 2.36 mm sieve. Do not oven dry the sample. By riffling or quartering, obtain a sample of about 35 g from the material passing the sieve. NOTE 1 The soil should be sufficiently dry so that it will pass the sieve. NOTE2 The preparation the sample from either an air-dried or natural state will produce different results. Therefore, it is recommended that samples are tested in the natural state. (b) Transfer 30土0.01g of the sample into a 100 mL beaker and add 75土0.05 g of distilled water. The temperature of the water shall be in equilibrium with the testing environment before commencing the test. . Stir the suspension regularly in the first 30 min, then cover the beaker with a cover glass and allow it to stand for at least 60 min. NOTE3 Highly plastic clays can require longer saturation to break up the clay particles. NOTE 4 For stabilized soils, the standing time should be not more than 2h, otherwise irreversible changes can take place in the stabilizers. [c) Calibrate the pH meter using . standard buffer solutions，in accordance with the manufacturer’s procedures. NOTE 5 A buffer solution that has a pH within 2 pH units the soil being measured should also be used. [d) Determine the pH of the distilled water. (e) Determine the temperature of the soil-suspension. [f) Wash the pH electrodes with distilled water and immerse them in the soil-suspension. Insert the electrode, ensuring it does not touch the sides of the beaker, such that it is suspended in the top of the soil suspension and not the super natant liquid. Take two or three readings of the pH of the soil-suspension. These readings shall not differ by more than 0.05 pH. Calculate the mean of the readings. NOTE 6 The pH readings the soil-suspension should reach a constant value in about 1 min. No readings should be taken until the pH meter has reached equilibrium. (g) Remove the electrodes from the suspension and wash with distilled water.