PROJECTS IN CONCRETE CONSTRUCTION 151 



upon the top of the forms. Avoid using too dry a 

 mixture for floor construction. 



5) The concrete may be shoveled directly from the mix- 

 ing board into the form, or handled by means of a 

 wheelbarrow. 



6) Level the material off and tamp it enough to force the 

 coarse material in from the surface, and bring enough 

 cement-sand mortar to the surface to make a smooth 

 finish. Slight tamping is also done to remove any air 

 or water bubbles from the material. A spade or board 

 should be pushed in along the side of the form so that 

 all coarse material will be worked back from the edge 

 of the walk. 



7 If the walk is to be 50' or more in length, an expansion 

 joint should be placed approximately every 50'. This 

 expansion joint can be provided by putting in a board 

 1/2" thick at intervals of 50', which should be removed 

 after the concrete has properly set, and the groove 

 filled with heavy asphalt or Tarvia. To leave the 

 board in place is worse than no expansion joint. This 

 practice is sometimes followed. 



8) It the material has been mixed to the right consistency, 

 the surface can usually be given its final finish within 

 one-half hour after placing. The first part of the 

 finishing should be done with a wood float, merely to 

 level off the surface and make a smooth job. If it is 

 desired to make a very smooth surface, continue the 

 finishing by using a steel trowel. The troweling proc- 

 ess tends to bring an additional amount of cement and 



