APPENDIX C-Continued 



ratio for the particular combination of ingredients, 

 needed to select proportions for a range of specified 

 requirements. 



A3.4.5 In laboratory tests, it seldom will be found, 

 even by experienced operators, that desired adjust- 

 ments will develop as smoothly as indicated in Table 

 A3.4.1. Furthermore, it should not be expected that 

 field results will check exactly with laboratory results. 

 An adjustment of the selected trial mix on the job 

 is usually necessary. Closer agreement between lab- 

 oratory and field will be assured if machine mixing 

 is employed in the laboratory. This is especially de- 

 sirable if air-entraining agents are used since the type 

 of mixer mfluences the amount of air entrained. Be- 

 fore mixmg the first batch, the laboratory mixer 

 should be "buttered" or the mix "overmortared" as 

 described in ASTM C 192. Similarly, any processing of 

 materials in the laboratory should simulate as closely 

 as practicable corresponding treatment in the field. 



A3.4.6 The series of tests illustrated in Table 

 A3. 4.1 may be expanded as the size and special re- 

 quirements of the work warrant. Variables that may 

 require investigation include; alternative aggregate 

 sources, maximum sizes and gradings; different types 

 and brands of cement; admixtures; and considerations 

 of concrete durability, volume change, temperature rise, 

 and thermal" properties. 

 A3.5 — ^Test methods 



A3.5.1 In conducting laboratory tests to provide 

 information for selecting concrete proportions, the 

 latest revisions of the following methods should be 

 used: 



A3.5,l.l For tests of ingredients; 



Sampling hydraulic cement— ASTM C 183 

 Specific gravity of hydraulic cement — ASTM 



C188 

 Sampling stone, slag, gravel, sand, and stone 

 block for use as highway materials — ASTM 

 D75 

 Sieve or screen analysis of fine and coarse 



aggregates— ASTM C 136 

 Specific gravity and absorption of coarse ag- 

 gregates— ASTM C 127 

 Specific gravity and absorption of fine ag- 

 gregates— ASTM C 128 

 Surface moisture in fine aggregate — ASTM C 70 

 Total moisture content of aggregate by drying 



—ASTM C 566 

 Unit weight of aggregate— ASTM C 29 

 Voids in aggregate for concrete — ASTM C 30 

 Fineness modulus— Terms relating to concrete 

 and concrete aggregates, ASTM C 125 

 A3.5.1.2 For tests of concrete: 



Sampling fresh concrete — ASTM C 172 



Air content of freshly mixed concrete by the 



volumetric method— ASTM C 173 

 Air content of freshly mixed concrete by the 



pressure method— ASTM C 231 

 Slump of Portland cement concrete — ASTM 



C143 

 Weight per cubic fool, yield, and air content 



(gravimetric) of concrete — ASTM C 138 

 Concrete compression and flexure test speci- 

 mens, making and curing in the laboratory — 

 ASTM C 192 

 Compressive strength of molded concrete cylin- 

 ders— ASTM C 39 



PROPORTIONS FOR NORMAL AND HEAVYWEIGHT CONCRETE 



Flexural strength of concrete (using simple 



beam with third-point loading)— ASTM C 78 

 Flexural strength of concrete (using simple 



beam with center point loading) — ASTM 



C293 

 Splitting tensile strength of molded concrete 



cyhnders— ASTM C 496 



A3.G — Mixes for small Jobs 



A3.6.1 For small jobs where time and personnel 

 are not available to determine proportions in accordance 

 with the recommended procedure, mixes in Table 

 A3!6,l will usually provide concrete that is amply 

 strong and durable if the amount of water added at 

 the mixer is never large enough to make the concrete 

 overwet. These mixes have been predetermined in con- 

 formity with the recommended procedure by assuming 

 conditions applicable to the average small job, and 

 for aggregate of medium specific gravity. Three mixes 

 are given for each maximum size of coarse aggregate. 

 For the selected size of coarse aggregate. Mix B is in- 

 tended for, initial use. If this mix proves to be over- 

 sanded, change to Mix C; if it is undersanded, change 

 to Mix A. It should be noted that the mixes listed in 

 the table are based on dry or surface-dry sand. If the 

 sand is moist or wet, make the corrections in batch 

 weight prescribed in the footnote. 



A3.6.2 The approximate cement content per cubic 

 foot of concrete listed in the table will be helpful in 

 estimating cement requirements for the job. These 

 requirements are based on concrete that has just enough 

 water in it to permit ready working into forms with- 

 out objectionable segregation. Concrete should slide, 

 not run, off a shovel. 



TABLE'A3.6. 1— CONCRETE MIXES FOR SMALL JOBS 



Procedure; Select the proper maximum size of aggrcg 

 Section 5 3 21. Use Mix B. adding just enough water to 

 a workable consistency. If the concrete appears to be 

 sanded, change to Mix A and. if it appears oversanded 

 to Mix C. 



produce 







Approximate weights of solid Ingredients 

 per cu (t of concrete, lb 



Maxi- 





Sand- 



Coarse a 



fgregale 



size of 

 aggre- 

 gate. 



Mix 



desig- 



Cement 



entrained 



Concrete 

 without 



Gravel 



crushed 

 stone 



Iron 



blast 



furnace 



Elag 



ij 



A 



25 



48 



51 



54 



47 





B 



25 



46 



49 



56 



49 





C 



25 



44 



47 



58 



51 



'^ 



A 



23 



4S 



49 



62 



M 





B 



23 



43 



47 



64 



58 





c 



23 



41 



45 



«6 



58 



1 



A 



22 



41 



45 



70 



81 





B 



22 



39 



43 



72 



S3 





C 



22 



37 



41 



74 



85 



Hi 



A 



20 



41 



45 



75 



85 





B 



20 



39 



43 



77 



87 





C 



20 



37 



41 



7» 



89 



2 



A 



le 



40 



45 



79 



89 





B 



19 



38 



43 



81 



71 





C 



le 



36 



41 



83 



72 



•Weights are 

 tabulated weigh 



for dry sand. 11 damp sand Is used, 

 t of sand 2 lb and. « vtry wtt sand 1 



UKd, 4 



Will be 

 Air-ent 



ralnmen 



ztf2 



1 to alle 

 «s, produ 



should be 

 male cycle 

 btained by 

 alr-entraln 



M the deiin 



used In al 

 s of freez 

 the use o 

 ng admixt 

 nded by 

 d air cont 



ng and 

 an air-e 

 ure. 11 ar 

 the man 

 ent. 



es which 

 thawinc- 

 ntralnini 

 admlx- 

 jiacturcr 



336 



