CHAPTERS REINFORCING STEEL-PURPOSE AND LOCATION IN CONCRETE GENERAL As previously explained in Chapter 3~ coccrctc is strong in (:. c. >mprt;s!iion, b Lt relatively_ weak in tension and st:car. Generally, wher~~r ren~1on i~ cue. ~L. the concrete is rcinforc. cd,vith rt;info Tt;mg ::. 1cel Quillily control of both concrete and reinforcing stttl is important to dem­ on=e to the Engineer or Architect that the spcci Jied design requirements a. re met. The compn::$$ \Vc strength or the ooricrete is verified by taking test eylindc,s as per ~,e Americai, Society for Tu;ting and Matc:rials (AS'llvl). Standard plasnc colds arc used which f Oml the concrete in:o res: cylinders 6 msaics in Ui. wnctcr 11nd 12 1m:~es hi&h After 7 to 28 da)'!; c,f caring, these cyl­ indmm, placed in a lnboraiory testing m,ehine and crushed in eompn:ssion, with g. wge readings take. non the machine to determine the crushing load. for example, where 3,000 psi concrclc is specified, the eylicd CJ1 afler 28 days should break at about 90,000 pounds load,.. shown in Fill· 6-1. P90,000 lb. Arta=i28. 27 in. 2 P--90,000 lb. Sid. Test Cylinclor 90000 ~3,110psl Fig. 6·1 Test Cylinders of Plain Concrete Placlng Allnforct,g Bors-1 0th fdillon 6-1 Section 609 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 6-9