CCIL Concrete Testing Technician Certification - A23.2-3C questions and answers

A23.2-3C
1. Scope - This Test Method specifies the procedure for making and curing compression test cylinders and flexural test beams from samples of plastic concrete. Procedures for both field and laboratory work are included.

ACI - American Concrete Institute

A23.2-3C
3. Summary - This Test Method is used to cast compressive or flexural strength test specimens and cure them on site prior to timely transportation to the laboratory for subsequent curing and strength testing.

A23.2-3C
4. Significance and use - This Test Method specifies the standard procedure for making, curing, protecting, and transporting concrete specimens.

4. Significance and use
If the specimens are made and standard cured as specified in this Test Method, the resulting strength data, when the specimens are tested in accordance with the relevant test method, may be used for the following purposes: - 1. acceptance testing for specified strength;
2. checking adequacy of mixture proportions for strength; and
3. quality control

4. Significance and use
If the specimens are made and field-cured as specified in this Test Method, the resulting strength data, when the specimens are tested in accordance with the relevant Test Method, may be used for the following purposes: - 1. consideration of whether the structure is able to be put into service;
2. comparison with test results of standard cured specimens or with test results from various in place test methods;
3. adequacy of curing and protection of concrete in the concrete structure; and
4. formwork or shoring removal time requirements.

5. Apparatus
5.1 Moulds for compression test specimens: - Use cylindrical moulds, meeting the requirements of CSA A23.2-1D, having nonabsorbent surfaces and sufficiently rigid to hold their shape during the moulding of the test specimens.
Do not use cardboard moulds for specified concrete strengths greater than 35 MPa.
Lightly coat reusable moulds with mineral oil or other suitable non-reactive form release material before use.

5.3 Tamping rod
For 100 mm x 200 mm cylinders, - se a round straight steel tamping rod 10 - 1 mm in diameter and between 450 mm and 600 mm in length, having at least one end rounded to a hemispherical tip.

5.3 Tamping rod
For cylinders 150 mm in diameter or greater and for rectangular moulds, - use a round straight steel tamping rod 16 - 1 mm in diameter and not less than 450 mm nor more than 600 mm in length, having at least one end rounded to a hemispherical tip.

5.4.1 Internal Vibrators
Internal vibrators shall have...
The frequency of vibration shall be... - ... rigid or flexible shafts and preferably powered by electric motors.
... 120 Hz or greater.

5.4.1 Internal Vibrators
The outside diameter of the vibrating element shall be...
The minimum length of the vibrating element shall be... - ... 20 to 40 mm.
... 50 mm less than the height of the mould being consolidated.

5.4.1 Internal Vibrators
For the vibration of cylinders, the ratio of the diameter of the cylinder to the diameter of the vibrating element shall be... - 4.0 or higher.

5.4.1 Internal Vibrators
For the vibration of beams, the diameter of the vibrating element, or thickness of a square vibrating element, - shall not exceed one third of the width of the mould.

5.4.2 External vibrators
If required.. - shall be of the table or plank type, having a minimum frequency of 60 Hz. A means of clamping the moulds securely to the apparatus shall be provided.
(A tachometer should be used to check frequency of vibration)

5.5 Small tools - Tools and items, such as shovels, pails, trowels, wood floats, blunted trowels, straightedges, scoops, rubber gloves, rulers, and a rubber or rawhide head mallet weighing approximately 0.6 - 0.3 kg, shall be provided.