# Effect of Super Retarder on Recycled Water and Concrete Properties of Waste Slurry in Mixing Plant
## 4 Results  
### Effect of Using a Single Super Retarder on the Setting Time of Waste Shurry Recycled Water  
Seven kinds of super retarders were selected, and the effect of different dosage of super retarders on the setting time of waste slurry recycled water was investigated by external doping method. Figure 2 shows the effect of 0.5%, 1.0%, 1.5%, 2.0% super retarding agent on the setting time of recycled water, the dosage of super retarding agent is the ratio of the mass of recycled water. As can be seen in Figure 2, after using 0.5% of super retarding agents, the four super retarding agents, SDP-90, ACS, PBTCA and HEDP-4 Na, can make the slurry recycled water setting time of more than 10 h, compared with the reference group of 7 h, it can be seen that the four super retarding agents 0.5% dosage of the retarding effect of the better. Among them, SDP-90 has the best effect on retardation of slurry recycling water, and the final measurement of the beginning of the setting time is 13 h. However, when using the two super retaders AA/AMPS or IDS, the setting time of the waste slurry recycled water was 7 h and 8 h, respectively, which was not much different from that of the reference group of 7 h. It can be seen that the retardation effect is not good when these two super retenders are used individually at a dosage of 0.5%. As can be seen in Figure 2, after using 1.0% of super retarding agents, SDP-90, ACS and PBTCA three super retarding agents make the slurry recycled water setting time more than 14 h, it can be seen that these three super retarding agents 1.0% dosage retarding effect is better. Among them, PBTCA super retarding agent has the best effect on retardation of slurry recycling water, and the final measurement of the beginning of setting time is 18 h. However, when using AA/AMPS or PAPEMP these two super retarding agents, the setting time of waste slurry recycled water is 7.5 h and 9.5 h respectively, which is not much different from the reference group of 7 h; when using HEDP-4 Na or IDS these two super retarding agents, the setting time of waste slurry recycled water is 10.5 h and 11 h  
Figure 2: Effect of different dosage of super retarder on the setting time of recycled water. (a) 0.5%, (b) 1.0%, (c) 1.5%, (d) 2.0%. respectively, which is insignificant compared to the reference group of retarding setting time. It can be seen that 1.0% dosage of AA/AMPS, PAPEMP retardation effect is not good, HEDP-4 Na, IDS retardation effect is general. As can be seen in Figure 2, after using 1.5% of super retarding agents, the three super retarders SDP-90, ACS and PBTCA make the slurry recycled water setting time more than 18 h, which can be seen that these three super retarders are more effective in the dosage of 1.5% to slow down the sloughing effect. Among them, PBTCA super retarding agent has the best effect on retardation of slurry recycling water, and the final measured start of setting time is 22.5 h. However, when using HEDP-4 Na or IDS, the setting time of waste slurry recycled water is 12 h, which is not obvious compared with the reference group; when using AA/AMPS or PAPEMP, the setting time of waste slurry recycled water is 8 h and 10 h, which is not much different from the reference group of 7 h; It can be seen that at 1.5% dosage of super retarding agent, the retarding effect of HEDP-4 Na and IDS is general, and the retarding effect of AA/AMPS and PAPEMP is not good. As can be seen in Figure 2, after using 2.0% of super retarding agents, the two super retarders ACS and PBTCA made the slurry recycled water setting time more than 27 h, which can be seen that the two super retarders in the dosage of 2.0% retardation effect is better.