AS 1012.8.4:2015 pdf free download – Methods of testing concrete Method 8.4: Method for making and curing concrete-Drying shrinkage specimens prepared in the field or in the laboratory

AS 1012.8.4:2015 pdf free download – Methods of testing concrete Method 8.4: Method for making and curing concrete-Drying shrinkage specimens prepared in the field or in the laboratory.
4.6 Mallet
The mallet used in the moulding of specimens shall comply with the relevant requirements of AS 1012.4.1.
4.7 Wooden float
A wooden float is the flat surfaced tool that is used for smoothing the surface of the moulded specimens.
5 SAMPLING ANP TEST SPECIMENS
5.1 General
Specimens may be prepared either in the laboratory or in the field. Particular care should be taken to ensure sampling and preparation are strictly in accordance with this Clause (5) as these activities are crucial to the accuracy and repeatability of the test. Full records shall also he kept for inclusion in the report (see Clauses 7 and 8).
5.2 Sampling
5.2.1 Field sampling
For concrete sampled in the field, the concrete sample shall be obtained in accordance with
AS 1012.1.
5.2.2 Laboratory sampling
For concrete made in the laboratory, the concrete sample shall he prepared in accordance with AS 1012.2.
5.3 Preparation of test specimens
5.3.1 General
At least three specimens shall be prepared for each sample of concrete. The nominal size of’ the aggregate in the concrete, in accordance with AS 2758.1, shall not exceed 40mm.
5.3.2 Sire and shape of standard lest specimens
The test specimen shall be a prism 75 mm x 75 mm and approximately 280 mm long. A stainless steel gauge stud shall he cast into each end of the specimen. The gauge studs shall be cast so that their principal axis coincides with the principal axis of the test specimen, and shall extend into the specimen approximately 1 5 mm.
In the field, store specimens for a period of not less than I 8 h from moulding, nor more than 24 h as follows:
(a) In a covered location adjacent to the moulding site, preferably indoors and protected from wind and extremes of temperature.
(b) Undisturbed in their moulds on a rigid horizontal surface, with lids fitted so as to prevent the loss of moisture from the specimen.
NOTE: The aim is to provide conditions for test specimens which give a maximum of protection
from extremes of temperatures and loss of moisture during their storage in the field. 6.3. 1.4 Non-compliance with initial curing conditions
When standard moist-curing does not commence within 27 Ii of moulding, the test results shall be liable to rejection. Under these circumstances the following data shall be recorded:
(a) The reason for the delay.
(b) The length o time between moulding and commencement of standard moist-curing.
(c) The ambient maximum and minimum temperatures in the locality of the curing.
NOTE: Unless otherwise specified, the temperatures from the nearest Bureau of Meteorology weather station are adequate.
6.3.1.5 Initial curing tinder non—siandard condnions
As soon as is practicable after a period of I 8 h from moulding, ransport specimens stored under non-standard conditions shall be transported to the laboratory for demoulding, such that they are placed under standard moist curing conditions within 24 h of moulding.
6.3.2 Dernoulding of specimens
6.3.2.1 General
Dernould specimens within 24 ±3 h from the time of moulding. Where variations to this time period are necessary, standard moist curing conditions shall be maintained during any additional curing period and full details shall he noted in the report.
Minor damage to the gauge studs may be repaired: however, the extent of this damage and details of any repairs carried out shall be noted and reported.
Take extreme care to ensure that the gauge stud is not disturbed while the gauge stud holder is being unscrewed from the stud.
NOTES:
I Some grades of concrete with specified compressive strength less than 10 MPa at 28 days will need at least 48 h after moulding before demoulding to avoid damage to the specimens.
2 If ihe damage to the gauge studs is restricted to dislodgment of one or both gauge studs, the studs may be carefully cemented in place by means of a suitable fast-setting cement. e.g. a catalyzed epoxy or polyester. It is. however, essential that the cement he allowed at least 24 h to harden before initial measurerment.