CORRUGATED BAR COMPANY, INC. 



Conveying and Placing. After the mixing of the concrete has been completed, 

 it shall be conveyed as rapidly as possible to the place of deposit. No concrete shall 

 be placed which has partly set. Where concrete is conveyed by spouting, the plant 

 shall be of such size and design as to insure a practically continuous flow in the spout. 

 The angle of the spout shall be such as to allow the concrete to flow without a separa- 

 tion of the ingredients. The spout shall be thoroughly cleaned by flushing before and 

 after each run. Where it is impossible to deliver the concrete at the place of deposit 

 without separation of the ingredients, the concrete shall be discharged upon a mixing 

 board where it shall be mixed by turning until of uniform consistency before placing 

 in the forms. 



The concrete shall be deposited in the forms in such a manner as will permit the 

 most thorough compacting obtained by working with a straight shovel or slicing 

 tool kept moving up and down until all the ingredients are in their proper place. 



Light horizontal reinforcement shall be raised from the bottom forms to allow the 

 flow of the concrete under it. Where chairs are used, or where heavy reinforcement 

 is definitely wired in place, the mass shall be thoroughly worked to insure contact of 

 the mortar with the lower face of the reinforcing material. 



Before concrete is placed upon previously poured concrete, care shall be taken to 

 remove all debris from the concrete surface. All laitance shall be removed and the 

 surface shall be thoroughly wetted and slushed with mortar consisting of one part 

 Portland cement and two parts fine aggregate. 



When it is necessary to stop pouring at a place where pouring will be resumed at a 

 later date, all necessary grooves for joining future work shall be made before the con- 

 crete has set. 



Construction Joints. Construction joints in colimms shall be located at the base 

 of the bell or flare occurring immediately below the floor slab in flat slab construction. 

 In beam and girder construction the joint in the columns shall be located at the base 

 of the lowest intersecting member at each floor. 



Vertical joints formed by bulkheads which it may be necessary to construct in slab 

 or beams shall be made at the center of the span of such slab or beam. In girders into 

 which intersecting members are framed at the center of the span, the bulkhead shall 

 be located within the middle third of the length of the span of such girder. On large 

 beams or girders these bulkheads shall be placed inclined upward toward the nearest 

 column. 



Horizontal joints in large girders or other massive units shall be properly keyed by 

 notching. 



Lintel beams, whether above or below the slab, shall be poured monolithically with 

 the slab. 



No construction joints shall be allowed in footings, the pouring to be continued until 

 the whole footing is completed to the base of the column. 



All other joints in pouring shall be made only upon the approval of the Engineer. 



Placing Concrete in Freezing Weather. No concrete shall be mixed or placed 

 at a freezing temperature unless special precautions are taken to prevent the use of 

 materials covered with ice crystals or containing frost, and to prevent the concrete 

 from freezing before it has set and sufficiently hardened. 



The material used shall be warmed well above the freezing point and the space of 



192 



