The materials used in road engineering should comply with the provisions specified in Table 1.
Table 1 Technical Requirements for Gypsum Dicalcium Sulfate
Item Unit Standard
1 Calcium sulfate dihydrate (CaSO4·2H2O) (dry basis) % ≥70
2 Attached water (H2O) (wet basis) % ≤25
3 Water-soluble pentoxide of phosphorus (P2O5) (dry basis) % ≤0.50
4 Water-soluble fluoride ion (F-) (dry basis) % ≤0.30
5 Chloride ion (Cl-) (dry basis) % ≤0.04
6 Water-soluble magnesium oxide (MgO) (dry basis) % ≤0.30
7 Water-soluble sodium oxide (Na2O) (dry basis) % ≤0.10
8 pH value — ≥6
Note 1: The pH value is agreed upon by the supplier and user. However, considering the actual situation of pavement materials, the minimum limit control is set at 6.
Note 2: Items 1 to 8 are tested according to the methods specified in GB/T 23456.
The leachate from gypsum dicalcium sulfate-based road materials after养护14 days should meet the requirements listed in Table 2.
Table 2 Limit Values for Leachate of Gypsum Dicalcium Sulfate-Based Road Materials
Item Unit Standard
1 Phosphate (as P) mg/L ≤0.5
2 Fluoride (as F-) mg/L ≤10
3 Total mercury mg/L ≤0.05
4 Total cadmium mg/L ≤0.1
5 Total chromium mg/L ≤1.5
6 Total arsenic mg/L ≤0.5
7 Total lead mg/L ≤1.0
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: The characteristic pollutants are extracted according to the methods specified in HJ 557.
Note 2: Testing for items 1 to 8 is conducted according to the methods specified in GB 8978; testing for items 9 to 11 is conducted according to the methods specified in GB 15580.
Cement should comply with JTG/T F20 specifications.
Coarse aggregate shall be determined based on road grade, following JTG/T F20.
Fine aggregate shall be determined based on road grade, following JTG/T F20.
The stabilizer should meet the relevant provisions of CJ/T 486.
Water used in mixing should comply with the requirements specified in JTG/T F20.
T/CPFIA 0010-2023 history
2023T/CPFIA 0010-2023 Phosphogypsum-based road construction materials