AS 1012.14:2018 pdf free download.Methods of testing concrete Method 14: Method for securing and testing cores from hardened concrete for compressive strength and mass per unit volume.
6 PROCEDURE
6.1 General
The procedure for securing, preparing and testing the cores is as follows:
(a) Secure the cores from the hardened concrete (see Clause 6.2).
(b) Prepare the cores for testing by trimming and conditioning (see Clause 6.3).
(c) Check the cores for rejection (see Clause 6.4).
(d) Test the cores for compressive strength and mass per unit volume (see Clause 6.5).
6.2 Securing the cores
6.2.1 General
The aim is to secure representative and undamaged cores free from embedded reinforcement and/or other objects with a ratio of length/diameter alter trimming of approximately 2:1 and surfaces that arc smooth, cylindrical and free from steps, ridges and grooves.
The diameter of cores shall be not less than the greater of 75 mm or three times the nominal size of coarse aggregate in the concrete as detailed in AS 2758.1.
Cores shall not be secured until the concrete is sufficiently strong to permit their removal without damage to the core that would render the cores unsuitable for testing (see Clause 6.4).
Wherever possible. cores shall be drilled perpendicular to the surface of the concrete. Cores should preferably be taken at points not near to formed joints, edges of a concrete clement or other areas which may reduce the representative nature of the core.
NOTE: Appendix B provides guidelines on securing cores.
6.2.2 Procedure
The procedure for securing the cores shall be as follows:
(a) Take the cores from a location and at a time as specified by the authority or designer where possible avoiding the reinforcement. Whenever possible locate the reinforcement with a calibrated cover meter, ground penetrating radar or other suitable device and where available referencing to as-built drawings.
(b) Secure the cores by carefully and slowly penetrating the core drill into the concrete so that the concrete will not be weakened by shock or by heating. Apply water to the cutting edge during the drilling process.
(c) Unless otherwise specified, drill further than the desired core length to ensure an adequate core length is secured for testing.
(d) Record the location and direction of coring for each core secured.
(e) Label each core, after extraction, with the location, top or outer surface end and unique identification.
(f) Handle and transport the cores carefully to avoid damage.
6.3 Preparation of cores
6.3. 1 Preparation
Cores shall be accepted for testing if they have been secured in accordance with Clause 6.2 and appear to be free from defects likely to affect their strength. The cores should be examined for—
(a) visible damage;
(b) presence of cracks;
(c) broken edges.AS 1012.14 pdf download.