PROJECTS IN CONCRETE CONSTRUCTION 141 



quantity of material needed for certain jobs. Make a 

 written report on results obtained. 



Tools Needed : Rule for taking dimensions. 



Preliminary Instruction: Carefully read the preceding para- 

 graphs. Keep in mind the general principles of con- 

 crete construction. Remember the requirements for 



FlG. 146-a. An attractive walk. 



well-made concrete, good aggregate, proper propor- 

 tions, careful mixing and placing, and correctreinf orcing. 

 Working Instructions: 



a) Examine at least one of each of the different types of 

 concrete work listed under requirements and report on the 

 following: 



1) General condition of the job. 



2) If cracks are forming, to what are they due? 



3) Where cracks have formed, note if there is a clear 



fracture, or, if the aggregate is pulled out of the 

 mortar. 



4) Was the coarse aggregate worked back from the 



form when placed? 



5) Was a dry, quaky or a wet mixture used? 



