Both the rate and the sequence of pouring shall be

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ure shall be determined in accordance with the method prescribed in Appendix Dof *IS: 456-1957. In the case of coarse aggregates, percentage of free water shall be determined by weighing a representative sample, then surface-drying each particle individually with a clean towel and reweighing the surface-dry sample to determine the amount of water removed. In calculating the water-cement ratio, the 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 consistency and quality throughout any pour and for similar parts of the However, the consistency and cQ_m.position shall be such same structure. that the concrete can be worked into all corners arid angles of the forms and that the concrete surrounds completely the reinforcement 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 under specific 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 practicable to the standard ratio the water-remen t ratlo :ib Closely U ii&Ymirled ds sy~c~Cifi~:ii i:ilci~br 4.2.1. 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, the consistency shall 1~: IIUCLWW~ 11y the use of Vce-Bee consistometer !-ire allouable slump or consistency shall be described in Appendix .\. determined 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, the cement or multipic and admistures, 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 b) proper adjustment of the proportions of th...
View Full Document

This document was uploaded on 10/01/2013.

Ask a homework question - tutors are online