APPENDIX C-Continued 



Fineness modulus 

 Specific gravity (BulkSSD) 

 Absorption (percent) 

 Dry rodded weight 

 Maximum size 



Fine aggregate Coarse aggregate 



165 lb per cu ft 



on the absolute volume basis. With the quantities of 

 cement, water, air and coarse a(!grc(,'atc established, 

 the sand content can be calculated as follows: 



Employing tlie sequence outlined in Section 5 of this 

 recommended practice, the quantities of ingredients per 

 cubic yard of concrete are calculated as follows: 



A4^.1 Step ]. As indicated above, the desired slump 

 is 2 to 3 in. 



A4.3.2 Step 2. The available aggregate sources have 

 been indicated as suitable, and the coarse aggregate will 

 be a well-graded and well-shaped crushed ilmenite 

 with a maximum size of 1 in. 



A4.3.3 Step 3. By interpolation in Table 5.3.3, non- 

 air-entrained concrete with a 2 to 3 in. slump and a 

 1 in. maximum size aggregate requires a water content 

 of approximately 310 lb per cu yd. The estimated en- 

 trapped-air is 1.5 percent. (Non-air-entrained concrete 

 will be used because (1) the concrete is not exposed to 

 severe weather, and (2) a high air content could reduce 

 the dry unit weight of the concrete.) 



Note: Table 5.3.3 values for water requirement are 

 based on the use of well-shaped crushed coarse aggre- 

 gates. Void content of compacted dry fine or coarse 

 aggregate can be used as an indicator of angularity. 

 Void contents of compacted 1 in. coarse aggregate of 

 significantly more than 40 percent indicate angular 

 material which will probably require more water than 

 that listed in Table 5.3.3. Conversely rounded aggre- 

 gates with voids below 35 percent will probably need 

 less water. 



A4.3.4 Step 4. From Table 5.3.4(a) the water-cement 

 ratio needed to produce a strength of 4500 psi in non- 

 air-entrained concrete is found to be approximately 

 0.52. 



A4.3.5 iitep 5. From the information derived in Steps 

 3 and 4, the required cement content is calculated to be 

 310/0.52 = 596 lb per cu yd. 



A4.3.6 Step 6. The quantity of coarse aggregate is 

 estimated by extrapolation from Table 5.3.6. For a fine 

 aggregate having a fineness modulus of 2.30 and a 1 in. 

 maximum size aggregate, the table indicates that 0.72 

 cu ft of coarse aggregate, on a dry-rodded basis, may be 

 used in each cubic fool of concrete. For a cubic yard, 

 therefore, the coarse aggregate will be 27 x 0.72= 19.44 

 cu ft. Since the dry-rodded unit weight of the coarse 

 aggregate is 165 lb per cu ft, the dry weight of coarse 

 aggregate to be used in a cubic yard of concrete would 

 be 19.44 X 165 — 3208 lb. The angularity of the coarse 

 aggregate is compensated for in the ACT proportioning 

 method through the use of the dry-rodded unit weight; 

 however, the use of an extremely angular fine aggre- 

 gate may require a higher proportion of fine aggregate, 

 an increased cement content, or the use of air-entrain- 

 ment to produce the required workability. 



A4.3.7 Step 7. For heavyweight concrete, it is recom- 

 mended that the required fine aggregate be determined 



Solid volu 

 Solid volu 



Solid volume of sand 

 Required vi'elght of 



^^^. ^ 1115 c 



- 19 W cu 

 :27 ~ 19-55 - 7.45tuf 



= 7.45 X 4.95 X 62,4 = 2301 lb 



A4J1.8 Step 8. Tests indicate total moisture of 0.15 

 percent in the fine aggregate and 0.10 percent in the 

 coarse aggregate; therefore, the adjusted aggregate 

 weights become: 



Fine aggregate (wet) = 1.0015 X 2301 = 2304 lb 

 Coarse aggregate (wet) = I.OOIO x 3208 = 3211 lb 



Absorbed water does not become part of the mixing 

 water and must be excluded from the adjustment in 

 added water. Thus surface water contributed by the 

 fine aggregate amounts to 0.15 — 0.55 = 0.10 percent; 

 by the coarse aggregate 0.10 — 0.08 = 0.02 percent. The 

 estimated requirement for added water, therefore be- 

 comes: 



310-2301(0.001) -3208(0.0002) = 307 lb 



A4.3.9 Step 9. The resulting estimated proportions 

 by weight of the heavyweight concrete becomes: 



Cement 



Fine aggregate (wet) 



Coarse aggregate (wet) 



Water 



Estimated unit wt (fresh) 



= 5961b 

 = 2304 lb 

 = 3211 lb 

 = 307 1b 

 -6418/27 = 237.7 lb per 



A4.4 — The above heavyweight concrete proportioned 

 mixture was actually used for approximately 5060 cu 

 yd. Field adjustments resulted in the following actual 

 batch weights: 



Cement 



590 1b 









Fine aggregate 



23101b 









Coarse aggregate 



3220 1b 









Water 



285 lb 



(plus 



a wal. 



er-reduclng agent) 



The actual field test results indicated the concrete 

 possessed the following properties: 



Unit weight (fresh) 



235.7 lb per cu 

 2.8 percent 



5000 psi at 28 days 



PROraBTlOKS FOR NORMAL AND HEAVYWEIGHT CONCRETE 



338 



