T/CPFIA 0010-2023 Phosphate slag-based road building materials

Scope

Main technical content: 4. Materials 4.1 Phosphogypsum used in road engineering shall comply with the requirements specified in Table 1. **Table 1: Technical requirements for phosphogypsum** **Item** **Unit** **Limit** 1 Calcium sulfate dihydrate (CaSO4·2H2O) (dry basis) wt% ≥70 2 Bound water (H2O) (wet basis) wt% ≤25 3 Water-soluble phosphorus pentoxide (P2O5) (dry basis) wt% ≤0.50 4 Water-soluble fluoride ions (F-) (dry basis) wt% ≤0.30 5 Chloride ions (Cl-) (dry basis) wt% ≤0.06 6 Water-soluble magnesium oxide (MgO) (dry basis) wt% ≤0.30 7 Water-soluble sodium oxide (NaO) (dry basis) wt% ≤0.10 8 pH value ≥6 **Note 1**: The pH value shall be agreed upon by both parties. However, based on the actual situation of road materials, the minimum limit is set at 6. **Note 2**: Items 1–8 shall be tested in accordance with the methods specified in GB/T 23456. 4.2 After curing for 14 days, the leachate of phosphogypsum-based road materials shall meet the requirements specified in Table 2. **Table 2: Limits for leachate of phosphogypsum-based road materials** **Item** **Unit** **Limit** 1 Phosphate (calculated as P) mg/L ≤0.5 2 Fluoride (calculated as F-) mg/L ≤10 3 Total mercury mg/L ≤0.05 4 Total cadmium mg/L ≤0.15 5 Total chromium mg/L ≤1.56 6 Total arsenic mg/L ≤0.57 7 Total lead mg/L ≤1.08 8 pH value 6–9 9 Chemical oxygen demand (CODCr) mg/L ≤70 10 Total nitrogen mg/L ≤15 11 Ammonia nitrogen mg/L ≤10 **Note 1**: Characteristic pollutants shall be tested in accordance with the methods specified in HJ 557. **Note 2**: Test methods for items 1–8 shall be implemented in accordance with GB 8978; test methods for items 9–11 shall be implemented in accordance with GB 15580. 4.3 Cement shall comply with the requirements specified in JTG/T F20. 4.4 Coarse aggregates shall be determined in accordance

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