T/KMSHJBHLHH 001-2025 Phosphate slurry cement concrete with recycled coarse aggregate

Scope

Scope: This standard specifies the terms and definitions, classification and specifications, requirements, test methods, inspection rules, marking, storage, and transportation of recycled coarse aggregates for phosphogypsum-based concrete. This standard applies to recycled coarse aggregates used in the preparation of phosphogypsum-based concrete; Main technical content: I. Terms and definitions clarify the meanings of the core terms in the standard, including: Phosphogypsum: a chemical by-product of the wet method for phosphoric acid production, mainly composed of calcium sulfate. Modified phosphogypsum: a phosphogypsum product that has been processed through washing and roasting to remove or transform contaminants. Recycled coarse aggregates for phosphogypsum-based concrete: particles with a diameter greater than 4.75mm, processed from modified phosphogypsum and other raw materials, used for preparing concrete. Key performance-related terms such as micro-powder content, needle-flake particles, crushing index, and compactness are also defined. II. Classification and marking Classification: divided into Class I, Class II, and Class III according to performance requirements. Specifications: divided into continuous grading (5mm～16mm, 5mm～20mm, etc.) and single grading (5mm～10mm, 10mm～20mm, etc.) according to particle size. III. Requirements 1. Raw material requirements: specify the technical indicators of phosphogypsum, including appearance (powdery and loose, no agglomeration), calcium sulfate dihydrate content (≥80%), adhered water (≤20%), water-soluble phosphorus pentoxide (≤0.30%), fluoride ions (≤0.20%), and the internal and external radiation indices of radioactivity shall all be ≤1.0. 2. Particle grading: specify the cumulative sieve pass requirements for different particle sizes (continuous grading and single grading), such as the cumulative sieve pass of 5～16mm continuous grading at the 4.75mm sieve being 85～100%, and that of 16.0mm sieve being 0～10% etc.

Development Information

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