Agriculture Reference
In-Depth Information
liasing with the author and producing trial rubbing bricks on his family prop-
erty. Made completely in the traditional manner (i.e. the first batch of bricks
were made with clay treaded by foot), these hand-moulded bricks made out of
a local south eastern Virginia clay with a high sand content, are fired with hard-
wood fuel in a clamp style kiln for around 4 days. These low-fired bricks are
then sorted based on colour and hardness. This allows for matching of existing
work such as their use in repairing segmented arches at the 1780's President's
House of the College of William and Mary. Though only a few thousand have
been made so far with moderate success, efforts to refine clay mixing and kiln
firing practices should help to improve future rubbing bricks production.
Sussex Handmade Bricks
Jason Whitehead
1934 Chinchilla Dr.
Sandston
VA 23150
USA
Te l :
(001) 804-677-9610
e-mail: muddypups@earthlink.net
The Frost Resistance of Rubbing Bricks
Many observers today observing rubbing bricks being abraded and cut so eas-
ily wonder about their ability to perform in the weather, particularly their frost
resistance. The hardness (compressive strength) and water absorptivity of
bricks are two properties often linked to their frost resistance. In this respect,
one might expect harder bricks with low water absorptivity to show a greater
frost resistance than soft rubbing bricks with high water absorption. These
properties, however, have never produced a dependable indication of frost
resistance. In his
Notes On Frost Resistance Of Clay Bricks
(Hammett, 2004) sev-
eral important points are explored that aid clarity of this subject, such as:
The physical characteristics of a fired clay body that make a brick or tile frost
resistant are not easy to determine or measure. Nor are they consistent. Several
clay manufacturing industry and academic research projects have explored the
phenomenon since the mid-twentieth century, but no practical method of pre-
dicting frost resistance has been devised.
Many bricks of only modest strength (7-20 N/mm
2
) and high water absorptivity
(20%-30%) have excellent resistance to damage by frost action.
There is no dependable correlation between strength or water absorption and
frost resistance. It is generally felt that resistance can be produced by either of
two different characteristics.
