Building Materials, Third Edition

PT f2w—

—

PII „iƒ„sxq2yp2f‚sguƒ

About fifty pieces of bricks are taken at random from different parts of the stack to perform
various tests. For the purpose of sampling, a lot should contain maximum of 50,000 bricks. The
number of bricks selected for forming a sample are as per Table 2.3, (IS: 5454). The scale of
sampling for physical characteristics is given in Table 2.4.

„—˜2PQ ƒ™—22ƒ—2—2€˜2x/˜22h™22†/—2—

h—2g——™™

x022˜

™ p2™——™



™2™



2 p2

—



22 



#

—2˜

™ ™——™™2™2

x022˜

™2 €



˜2x02  22PH2˜™"#x

˜2™ ™

#2

22— 2˜™"22˜2™

PHHI22IHHHH PH I RH

IHHHI22QSHHH QP P TH

QSHHI22SHHHH SH Q VH

x

X2s 2™—
2 
2 2™ — 2PHHH22
2˜™D2 
2— 2—2˜
2˜:
™ 2 2—


2˜
"


2™—
2— 2


„—˜2PR ƒ™—22ƒ—22€+™—2g——™™

v2

) ƒ—

2

)22™

# €



˜ ‡——   

D2˜—

2—D2—# x02 ƒ—

 €

˜2x 0

D2˜2

D2$— ™

#2 & 2™

—˜

2—2™™ ™™

PHHI22IHHHH S H IH H

IHHHI22QSHHH IH H PH I

QSHHI22SHHHH IS I QH P

xXs 2™—
2 
2 2™ — 2PHHH22
2˜™D2 
2— 2—2˜
2˜:
™ 2 2—


2˜
"


2™—
2— 2


h „2@sƒX2IHUUAX 20 pieces out of selected
pieces (Table 2.3) are taken and are laid flat as shown
in Fig. 2.14. The cumulative dimensions of the bricks
should be as discussed in Sec. 2.5.
The tolerances (Section 2.5) on the sizes of bricks
are fixed by giving maximum and minimum
dimensions, not on individual bricks but on batches
of 20 bricks chosen at random.
It follows from this method of measurement that
batches are likely to contain, bricks outside the
prescribed limit of tolerance. Such lots should be
rejected to avoid complaints about the variation of
perpends.
p2PIR w—/ 22„ —™2
g2f/2f ™