Concrete. Determination of starting and finish setting times by the measure of penetration resistance.
The method is used to determine the setting times of concrete by measuring the progressive penetration resistance (over time) by means of a suitable penetrometer. The penetration resistance is measured on the mortar obtained by previously sieving the concrete under test, according to the procedures specified below. This method is valid in those cases where the mortar separated from the concrete can be representative of the behaviour of the whole concrete. This method can therefore be used to determine the influence that certain variables, such as temperature, cement quality, dosage, presence of admixtures, etc., may have on the setting and early hardening of concrete. The initial setting time of concrete is defined as the time interval elapsing from the addition of water to the mix until the mortar sieved from the concrete offers a penetration resistance of 35 kgf/cm2 (343 N/cm2). The final setting time of concrete is defined as the time interval elapsing from the addition of water to the mix until the mortar sieved from the concrete offers a penetration resistance of 280 kgf/cm2 (2746 N/cm2). Apparatus. Preparation of the mortar sample. Procedure. Expression of results.
