AS/NZS 4456.11:2003 pdf.Masonry units and segmental pavers and flags – Methods of test   Part11:Determining coefficients of expansion.
This Standard sets out the methods for determining the coefficients of expansion of masonry units, segmental payers and flags. The coefficients of expansion estimated by these tests represent the total 15 year expansion of either kiln-fresh or non-kiln-fresh fired clay units. Provision is also included for the estimation of past expansion and of residual expansion to 15 years. of units of any age.
2 REFERENCED DOCUMENTS
The following document is referred to in this Standard:
AS/NZS
4456 Masonry units, segmental payers and flags—Methods of test
4456.0 Part 0: General introduction and list of methods
4456.1 Method 1: Sampling for testing
4456.2 Method 2: Assessment of mean and standard deviation
3 DEFINITIONS
For the purpose of this Standard. the definitions given in AS/NZS 4456.0 apply.
5 COEFFICIENT OF EXPANSION OF FRESH UNITS
5.1 Principle
A sample of 5 units is used. (For burnt clay building bricks, they represent the range of’ the firing treatments of the product. They are taken either from the kiln or from the packaging line and their temperature allowed to equilibrate).
Ref’erence points are established in the ends of the units and the distances between the points are measured between 24 h and 32 h alter the units are drawn from the kiln (see Note 1). The units are then exposed to saturated steam at 100°C (see Note 2) for 4 h. after which they are cooled and re-measured when their temperature is within 2°C of’ the temperature at which they were lirst measured and within 1 00 h of the taking of that trst measurement. The difference in length multiplied by an appropriate factor gives the coefficient of expansion — the em’ value.
NOTES:
I Because at least one day will have elapsed between the end of tiring and the first possible occasion when they can be sampled, fired bricks from batch kilns should have their first measurement taken as soon as temperature equilibration has occurred.
2 See Clause 5.8 for corrections for locations where water boils at temperatures less than
100°C.
5.2 Apparatus
The following is required:
(a) Temperature-controlled space in which the temperature does not differ by more than 2°C between the taking of the initial and final gauge readings of the units.
(b) Measuring frame, of a suitable type, fitted with a micrometer or dial gauge that is capable of being read to the nearest 0.002 mm or better (see Figure 1).
(c) Flat-ended reference bar of invar steel rod fitted with an insulated grip and approximately equal in length to the test specimens.
(d) Two steel balls of 6.5 mm diameter.
(e) Two steel-ball adaptors that can be attached to the reference bar (see Figure 2).
(f) Calliper capable of being read to 0.5 mm over the length of the units being tested.
(g) Well-insulated, loosely covered boiler capable of holding at least 5 units without them touching each other. It shall be complete with a grid to support units clear of the boiling water and he large enough to hold sufficient water to last for the duration of the test. A thermometer shall be fitted to measure the temperature close to and at the top of the units.