Table 1. Typical Features of the two Main Current Tendencies in the Design of RCC Dams
|
All RCC dams |
Compound RCC dams |
Concrete consistency |
Low VeBe times (10-15 secs) |
Medium & high VeBe times (>25 secs) |
Water/cement ratio |
0.50 – 0.70 |
0.80 – 1.20 |
Use of pozzolanic material and mix retardation |
>50% of total cement content and highly retarded mix |
<25% of total cement content and mix not specially retarded |
Construction of lift joints |
Surface paste that is brought up during compaction of the RCC |
Improved by bedding mixes that are manufactured separately |
Water-tightness |
Impervious and monolithic RCC matrix and lift joints |
Upstream waterproof membrane |
Interfaces |
Grout-enriched RCC |
CVC, pre-cast panels or grout enriched RCC |
Possible speed of construction |
Very high (average can be more than 100,000m3/month) |
High (but average less than 65,000m3/month) + membrane |
Performance |
Very good if properly designed and constructed |
Very good if properly designed and constructed |
Cost for each particular site (see section 3) |
Can be 25% to 30% less than CVC dams |
Between 5% and 20% more than the all-RCC dam |