238 



FAEM BUILDINGS IN SOUTH AFRICA 



way we can be absolutely sure that every particle has been turned 

 the required number of times ; and we must bear in mind that reinforced 

 concrete work requires careful supervision to see that instructions such 

 as the above are carried out to the letter. 



As concrete sets quietly, we must mix it up in small quantities 

 as required, and deposit in position at once. 



Construction. — The hard core having been deposited, put down a 

 layer of concrete 2£ inches thick on the bottom of the swim, and ram 

 it well. On top of this layer the iron reinforcement is laid. First 

 the V-shaped rods are put in position ; these are \ inch in diameter, 

 and the rods which form them should be bent so that the centre line 

 of each leg is exactly 2 inches from the outer face of each wall. It may 

 be mentioned that in all reinforced concrete work the reinforcement 

 should be placed exactly as specified and as shown on the drawings. 

 Here again careful supervision is required. 



On top of the bottom portion of the above rods the five |-inch rods 

 which run parallel to the length of the dip are placed, being equally 



spaced and tied with soft wire 

 where they cross the £-inch rods. 

 These five rods are carried up 

 the outslope, and also up the 

 vertical wall at the in-end of 

 the tank. All joints in the 

 length of the rods should be 

 made as shown in Fig. 188, 

 having a 12-inch lap tied with 

 soft wire, the ends being bent 

 over at least 1 inch as shown, 

 so as to anchor each rod securely 

 in the concrete. These joints 

 are necessary in lengths of rod 

 longer than 12 feet, as the iron 

 is sold in 12-foot lengths. 

 The rods having been carefully placed as above, the concrete surface 

 on which they lie is brushed over with a thin layer of a mixture of 1 

 part cement to 1 part sand. This is called " grouting." The grout 

 should not be applied over the whole surface at once, but only a small 

 part should be grouted and then covered immediately with the remaining 



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