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Unformatted text preview: ure shall be determined
method prescribed in Appendix Dof *IS: 456-1957.
In the case of coarse
of free water shall be determined
by weighing a
sample, then surface-drying
each particle individually
a clean towel and reweighing
sample to determine
amount of water removed.
total weight of water in the mixture including all free water in the aggregate but not including
any absorbed moisture,
shall be taken into consideration.
4.4 Workability - As far as possible the concrete shall be of uniform
and quality throughout
any pour and for similar parts of the
However, the consistency
and cQ_m.position shall be such
that the concrete can be worked into all corners arid angles of the forms
and that the concrete surrounds
and embedded metal without causing any segregation
of the ingredients
or collection of free water.
To this end, the mix may be adjusted slightly asprovided und$r 4.2, if necessary, to provide more workability
conditions, only if no change in the method of either placing or compacting
will accomplish the desired result.
* Swxnd revision in 1964.
10 IS : 457 - 1957
4.5 Si~lmp ‘.- The !-orltrr,l of concrete under thil; code is based on maintaining a fGrly unifrirn: k.i~:~!i;i ;;t the poirlt of pi:,cement and on holding
to the standard
the water-remen t ratlo :ib Closely
LJntlt*rIIOcor:ditions shall the slump
be greater than that rt*cirrirctf to pr.ovl~l~~prof~r pl~~~ernent and compaction
of the fresh concr’ctt~ ;viiilin the forms.
Tlw slump ~XtlnllIY n~cast~rc~d in :i(:cordClncc witi. the method prescribed
in Appendix G ot *is: 156 10.57. In the c.ise of wi y small or zero slump,
shall 1~: IIUCLWW~ 11y the use of Vce-Bee consistometer
slump or consistency
described in Appendix
by thus ,,!li:il,,,t,r-i:l-ctlar~t,~ and no cll;Lnge in consistency shall
be made \vitlr!,rrt his .ti?:~r,>~~~l. 4.4 Measurement of Mater ials 4.6.1 The method of measuring materials for concrete shall be such
that the proportions
are controlled and readily checked at any time during
Xnterials shall be measured as follows:
the progress of the irork.
Each size of aggregate shall be weighed separately,
if sly, shall he weighed in intli\5dunl
batches as approved by the en~irieer-in-cllargc.
4.6.2 WeiPh B&hers .- AI1 we+hine devices shall be subiect to anI
and weygh hatchers shall meet the following requirements:
The accuracy shall be of the order set for the purpose and shall be
such tllat the indicated weight of any hopprr full of material does
not vary more than one percent from the required weight.
The weighing equipment
shall be designed to permit ready and
of the proportions of th...
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This document was uploaded on 10/01/2013.
- Fall '13