BNBC Proportioning by Water Cement Ratio
Md. Ashraful Haque, 17-Nov-2012
ভিউ : 70343
5.6.3 Proportioning by Water Cement Ratio
5.6.3.1 If the data required in Sec 5.6.2 are not available, concrete proportions shall be based on water cement ratio limits specified in Table 6.5.6 when approved by the engineer.
Table 6.5.6
Maximum Permissible Water Cement Ratios for Concrete when Strength Data
from Field Experience or Trial Mixtures are not Available
Specified Compressive | Absolute Water Cement Ratio by Weight | |
N/mm2
| Concrete other than air-entrained | Air-entrained |
17 | 0.66 | 0.54 |
* 28 day strength. With most materials, water cement ratios shown will provide average strengths greater than that required in Sec 5.6.2.2. |
5.6.3.2 Table 6.5.6 shall be used only for concrete to be made with cements meeting strength requirements for Types I, IA, II, IIA, III, IIIA, or V of "Specification for Portland Cement" (ASTM C150), or Types IS, IS-A, IS (MS), IS-A(MS), I(SM), I(SM)-A, IP, IP-A, I(PM), I(PM)-A, IP(MS), IP-A(MS), or P of "Specification for Blended Hydraulic Cements" (ASTM C595), and shall not be applied to concrete containing lightweight aggregates or admixtures other than those for entraining air.
5.6.3.3 Concrete proportioned by water cement ratio limits prescribed in Table 6.5.6 shall also conform to special exposure requirements of Sec 5.5 and to compressive strength test criteria of Sec 5.12.
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