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3.3. Texture Change of PWM Slurry Considering the optimization of slurry texture and compressive strength, the wood chips were added to the slurry as seen in Table 4. Both wood chips and paper sludge improved the property of the stress-time curve. In addition, 5% of wood chips were used to gradually replace the paper sludge in the mixing proportion of up to 20% of the total weight. It can be seen from Figure 8 that when wood chips were added from 10% (PWM3-3) to 15% (PWM3-4) of the total weight, the compressive strength was at a steady stage (nearly 25 MPa), with both stony and woody textures starting to appear clearly on the surface of the mud (Figure 9). Considering the possibility of adding wood chips as decoration materials, it is appropriate to add 15% of wood chips and 5% of paper sludge to the mixture.
Table4. Experimental parameters of PWM3 series substitution proportion.
Solid Materials wt.%
Experiment No.
Lime Mud
Paper Sludge
Wood Chips
Ms
AE
W/B
BFS
PWM3-1 PWM3-2 PWM3-3 PWM3-4
70 70 70 70 70
10 10 10 10 10
20 15 10
0 5
10 15
10% 0.93
0.5 9 of 12
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5 0
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PWM3-5 20 Legend: AE—Alkali equivalent; Ms—Silicate modulus; W/B—Water-binder ratio; wt.%—weight percentage.
Figure 8. The compressive strength of PWM3 series. Figure 8. The compressive strength of PWM3 series.
Figure 9. The change of texture in terms of PWM. Figure 9. The change of texture in terms of PWM. Figure9. The change of texture in terms of PWM.
3.4. Effect of Declining Alkali Equivalent Given the simplified process for producing alkali-activated cementitious materials and the convenience of storing and transporting raw materials, only sodium silicate pow- 3.4. Effect of Declining Alkali Equivalent Given the simplified process for producing alkali-activated cementitious materials and the convenience of storing and transporting raw materials, only sodium silicate pow- der was used to prepare alkali activators in this study. Therefore, the silicate modulus (Ms) of alkali activators was a constant value and the ingredient of alkali activators could
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