Page 147 - Water Standards
P. 147

3) The number of trans⁃shipment times shall be minimised as
                                much as possible. If aggregate of particle size larger than
                                40mm falls through a drop of more than 3m in disposal,
                                descent control devices should be set up.
                       3   3   4  Concrete batching systems shall meet the following require⁃
                       ments:
                           1  Calculation of concrete production capacity:
                             1) Concrete production capacity is calculated according to E⁃
                                quation (3   3   4-1):
                                                     q
                                                P =    k              (3   3   4 - 1)
                                                    nm
                       Where:
                                                          3
                           P = concrete production per hour, m / h;
                                                                       3
                           q = concrete pouring intensity in the peak month, m / month;
                           m = daily work hours, h, which may be set at 20;
                           n = monthly work days, d, which may be set at 25;
                           k = uniformity coefficient, that is the ratio of actual maximum
                              hourly pouring intensity in the peak month to the average
                              hourly intensity of the total month, which may be set at 1   5  
                             2) If the pouring area is quite large, the hourly concrete pro⁃
                                duction capacity shall ensure that no concrete initial setting
                                occurs. If the concrete is poured by the horizontally sprea⁃
                                ding method, Equation (3   3   4-2) shall be employed for
                                calculation:
                                                       ∑(F·δ)   max
                                      P ≥ (1   1 - 1   2)             (3   3   4 - 2)
                                                         t - t
                                                          1   2
                       Where:
                           ∑ (F · δ)    = maximum simultaneous pouring volume of all
                                      max
                                          pouring layers;
                                       F = pouring area;
                         1 4 0
   142   143   144   145   146   147   148   149   150   151   152