Sustainability 2022 , 14 , 13536 Sustainability 2022 , 14 , x FOR PEER REVIEW
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( a ) ( b ) Figure 3. The experiments process record in the laboratory. ( a ) The material mixing process. ( b ) The performance test. 3. Results and Discussion This study classified the BFS substitution from wastes in papermaking into two path- ways: SPW substitution and PWM substitution. In both pathways, the effects of these wastes on mechanical properties and texture were investigated. The suitable AE values were also analyzed. 3.1. Effect of Single-Type Paper Waste (SPW) Substitution Proportion The experiment parameters of the SPW substitution are shown in Table 2 and the compressive strengths of samples are illustrated in Figure 4. The compressive strengths for different experimental series ranged from 14.5 MPa to 73.7 MPa after 28 days of curing. In terms of the SPW substitution proportion, the highest compressive strength was 73.7 MPa, in which BFS was partially substituted by 10% of the lime mud. The weakest com- pressive strength was 14.5 MPa, in which wood chips partially replaced 30% of BFS. Un- der the same substitution ratio, the compressive strength of lime mud, paper sludge, bot- tom ash, and wood chips sequentially decreased. The early strength illustrated that the compressive strengths of the sample increased rapidly from 0 to 7 days, almost exceeding 85% of the final strength. Except for the decrease in the compressive strength values of samples with the addition of sawdust from 7 to 28 days, the trend of strength development remained relatively constant, with some values fluctuating. This study classified the BFS substitution from wastes in papermaking into two pathways: SPW substitution and PWM substitution. In both pathways, the effects of these wastes on mechanical properties and texture were investigated. The suitable AE values were also analyzed. 3.1. Effect of Single-Type Paper Waste (SPW) Substitution Proportion The experiment parameters of the SPW substitution are shown in Table 2 and the compressive strengths of samples are illustrated in Figure 4. The compressive strengths for different experimental series ranged from 14.5 MPa to 73.7 MPa after 28 days of curing. In terms of the SPW substitution proportion, the highest compressive strength was 73.7 MPa, in which BFS was partially substituted by 10% of the lime mud. The weakest compressive strength was 14.5 MPa, in which wood chips partially replaced 30% of BFS. Under the same substitution ratio, the compressive strength of lime mud, paper sludge, bottom ash, and wood chips sequentially decreased. The early strength illustrated that the compressive strengths of the sample increased rapidly from 0 to 7 days, almost exceeding 85% of the final strength. Except for the decrease in the compressive strength values of samples with the addition of sawdust from 7 to 28 days, the trend of strength development remained relatively constant, with some values fluctuating. Figure3. The experiments process record in the laboratory. ( a ) The material mixing process. ( b ) The performance test. 3. Results and Discussion
Table 2. Experimental parameters of SPW substitution proportion. Table2. Experimental parameters of SPW substitution proportion.
Solid Materials wt.%
Solid Materials wt.%
Experiment No.
Lime Mud
Bottom Ash
Paper Sludge
Wood Chip
Ms
AE
W/B
Experiment No.
BFS
Lime Mud
Bottom Ash
Paper Sludge
Wood Chip
AE
Ms
W/B
BFS
S0
100
–
– – – –
– – – – – – –
– – – – – – – – – –
S9L1 S8L2 S7L3 S9B1 S8B2 S7B3 S9P1 S8P2 S7P3 S9W1 S8W2 S7W3
90 80 70 90 80 70 90 80 70 90 80 70
10 20 30
S0
100
--
-- -- -- --
-- -- -- -- -- -- --
-- -- -- -- -- -- -- -- -- --
S9L1 S8L2 S7L3 S9B1 S8B2 S7B3 S9P1 S8P2 S7P3 S9W1
90 80 70 90 80 70 90 80 70 90
10 20 30
0.5
– – – – – – – –
10 20 30
0.5
10% 0.93
– – – – – –
10 20 30
-- -- -- -- -- -- --
10 20 30
10%
0.93
0.6
– – –
10 20
-- -- -- --
10 20 30
– 30 Legend: AE—Alkali equivalent; Ms—Silicate modulus; W/B—Water-binder ratio; wt.%—weight percentage.
0.6
--
10
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