AS 1012.9:2014 Methods of testing concrete
7 TESTING MACHINES
The testing machine shall comply with the following requirements:
(a) The machine shall meet the requirements for Grade A machines defined in AS 2193 for the relevant range of compressive forces.
(b) The machine shall be power operated and capable of applying compressive forces increasing continuously at the rate of loading and in the manner specified in Clause 8.
(c) The machine shall be fitted with a load pacer which can operate at a rate of loading specified in Clause 8.
(d) The machine shall be fitted with two steel compression platens with hardened faces (see Note 1). The upper platen shall incorporate a spherical seat and the lower platen shall be movable along a vertical line only. The size of each platen shall be such that at least 10 mm clearance is provided between the edge of the specimen and the edge of the platen.
(e) The bearing surface of each platen that is in contact with the specimen or cap shall not depart from a plane by more than 0.02 mm at any time during service. It shall not depart from a plane by more than 0.01 mm when new or after re-machining (see Note 2).
(f) The centre of curvature of the spherical seat shall be on the vertical axis of the upper platen and shall be within 6 mm of the platen face. The upper platen shall be capable of limited movement and tilting by at least 3° in any direction. The spherical seat shall be free from grit and other foreign matter and shall be lubricated at all times (see Note 3).After the initial tilting of the upper platen to take up the end condition of the specimens, the upper platen shall lock in place during subsequent loading.
(g) The lower platen shall be provided with means for the accurate centring of specimens.Finely scribed markings shall be provided for the centring of specimens. These markings shall be disregarded when a platen is examined for planeness. Auxiliary steel platens of thickness not less than 15 mm, which meet the requirements of normal platens in respect to hardness, planeness and lateral dimensions, may be interposed between the specimen and the platen.