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2.2 Mixture Proportions

Two distinct control mixtures of concrete−with the same types of materials but with different proportions− were used in the experimental program. As summarized in Table 1, the two control mixtures were denoted C10 and C20. These control mixtures were subsequently modified by using a high-range water-reducing admixture to increase slump (C11, C12, C13,C21, C22), incorporating a viscosity-modifying admixture (VMA) to increase viscosity (C14), or adding water to increase slump (C23). A total of nine concrete mixtures were tested in this study.

Table 1. Mixture proportions a
  First concrete batch
(50 % Capacity)		   Second concrete batch
(100 % Capacity)		  
  C10 C11 C12 C13 C14 C20 C21 C22 C23
Gravel
(oven dry)		 3 1099.4 ←-------- Constant ---------→ +640.4 ←------ Constant -------→
Sand
(oven dry) 		kg/m3 774.0 ←-------- Constant ---------→ +1042.8 ←------ Constant -------→
Water
(free and absorbed)		 kg/m3 145.8 ←-------- Constant ---------→ +157.0 ←------ Constant -------→
Cement kg/m3 163.7 ←-------- Constant ---------→ ←------ Constant -------→
Slag kg/m3 163.2 ←-------- Constant ---------→ +223.1 ←------ Constant -------→
Set
retarder		 L/m3 0.656 ←-------- Constant ---------→ +1.0 ←------ Constant -------→
HRWRAL/m3 0 +1.4 +1.4 +0.6   +4.0 +4.0   
VMA L/m3 0     +0.2        
Testing time h 0.5 1.0 1.5 2.0 2.4 0.5 1.0 1.6 2.1
Temperature ºC 18 19.5 20 20 21 29.5 30 31 31
Slump mm 70 110 170 240 150 60 120 60 40
a The water quantity calculations take into account the initial moisture contents of the aggregates.

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