83 



The removal of the forms and false work will reveal 

 any weak points that may exist. 



The approval of the engineer or of the architect 

 must be obtained before the removal of the false work 

 is commenced. Test cubes must be consulted in order 

 to determine the condition of the concrete prior to the 

 removal of the forms. 



Warm, dry weather is the most favorable for the 

 rapid setting of concrete. Cool, damp weather retards 

 iting of concrete, and in very hot weather it 

 must be wetted to prevent rapid setting. In cold 

 weather the greatest amount of care should be used. 

 More time will be saved by being careful than by 

 rushing matters and having an accident. 



Frozen Concrete. Concrete will not set while froz- 

 en and it is difficult, if not impossible, to judge the 

 condition of frozen concrete. False-work must never 

 be removed while the concrete is frozen. Frozen con- 

 crete can be thawed out by artificial heat, if necessary, 

 and its c et and hardness can then be determined. Great 

 care is necessary in order to be absolutely certain that 

 the concrete is thoroughly thawed out. 



It is impossible to give any certain rule in regard to 

 the kngth of time which must be permitted to elapse 

 before the removal of the false work and forms is 

 commenced. The removal of the forms should not be 

 begun until the concrete is thoroughly set. The in- 

 spector must personally satisfy himself in regard to the 

 condition of the concrete, which must be hard and 

 should ring when struck with a hammer. 



Column f :ld be left in position for at least 



seven clays, r.n.kr favorable conditions Upon their 

 al the column should be carefully inspected and 

 its soundness approved. 



The of the surface to the air facilitates 



the setting of concrete. It is not good for the sur- 

 faces, how 



The wedges under the posts supporting the slab 



