GOST 25818-2017 PDF

Full title and description

GOST 25818-2017 — Thermal plant fly-ashes for concretes. Specifications. (Russian: «Золы-уноса тепловых электростанций для бетонов. Технические условия»). The standard establishes terminology, classification, quality requirements and rules for sampling, testing, marking, packing, storage and use of fly-ash (pulverized ash) from thermal power plants when used as a mineral additive in concrete and related cementitious materials.

Abstract

This interstate (GOST) standard sets technical conditions for thermal power plant fly-ashes intended for use in concretes. It defines material classes and types, allowable chemical and physical property limits (including free CaO, sulphate content, soluble phosphates), pozzolanic activity (activity index at 28 and 90 days), methods and frequency of sampling and testing, requirements for acceptance, marking, packaging, storage and transport, and requirements for control of potentially hazardous and radioactive constituents. The standard is intended to ensure predictable performance of concrete mixes containing such fly-ashes when correctly specified and tested.

General information

• Status: Active / In force (межгосударственный стандарт, действует).
• Publication date: Designation year 2017; introduced into force 1 March 2018 (date of introduction / effective date).
• Publisher: Interstate Council for Standardization, Metrology and Certification (EASC) / adopted and registered by national bodies (e.g., Rosstandart and adopted as national standard in member states).
• ICS / categories: 91.100.15 (Materials for civil engineering; mineral additives for concrete).
• Edition / version: Edition 1 (GOST 25818-2017).
• Number of pages: 23–24 pages (typical published electronic/print version lists 24 pages).

Information sources and official registrations indicate the standard was registered and came into effect in early 2018 under the designation GOST 25818-2017.

Scope

Applies to fly-ashes (pulverized combustion residues) produced by thermal power plants and intended for partial replacement of cement or as mineral filler in concrete, mortar and dry mixes. The standard covers classification of ashes by chemical nature and properties, specification of limits for contaminants and deleterious components, methods for determination of pozzolanic activity and physical parameters, sampling procedures for production lots and consignments, and recommendations/limitations for use in various concrete types (including requirements for freshwater vs. marine or hydraulic structures). It also addresses control of radionuclide activity and hazardous constituents where applicable.

Key topics and requirements

• Classification and types of fly-ash for concrete uses (different classes/types based on chemical/physical properties and intended application).
• Chemical limits and composition requirements (e.g., limits on free CaO, total sulphates (SO₃), soluble phosphates — soluble phosphates (as P₂O₅) not to exceed 100 mg/kg, and limits on alkalis and other oxides where specified).
• Pozzolanic (activity) index requirements: activity index thresholds specified (commonly cited values — not less than 75% at 28 days and not less than 85% at 90 days — for suitability as a pozzolanic additive).
• Physical requirements: fineness, true and bulk density, moisture content and allowable variation on delivery.
• Sampling and testing protocols: frequency of testing (weekly/monthly/quarterly depending on parameter), use of combined samples from point samples, and specified test methods or cross-references to relevant GOST methods.
• Acceptance, marking, packing, storage and transport requirements to preserve quality and traceability.
• Requirements for monitoring hazardous substances and radionuclide activity (annual checks for specific radionuclides; additional tests when fuel type or combustion conditions change).
• Application guidance and limitations (e.g., cumulative sulphate content limits in concrete and recommended proportions when replacing cement or fine aggregate, and specific notes for use in underwater/hydrotechnical constructions and lightweight concretes).

These requirements are stated to ensure consistent performance when fly-ash is used as a mineral additive in structural and non-structural concretes.

Typical use and users

Primary users: concrete and cement producers, ready-mix concrete suppliers, precast concrete manufacturers, material testing laboratories, construction designers and engineers specifying concrete mixes, regulatory and conformity bodies, and ash producers (thermal power plants). Typical uses include partial replacement of cement in normal and special concretes, filler in mortars and dry mixes, density reduction in certain lightweight concretes, and specific applications where pozzolanic properties improve durability or reduce cement consumption.

Related standards

GOST 25818-2017 cross-references and is used alongside other standards for testing and materials, for example standards for density determination (GOST 310.2 / GOST 30744), sand and aggregates (GOST 8736, GOST 8269.0), methods for determination of phosphates and chemical oxides (e.g., GOST 20851.2), and general standards on admixtures and concretes. Users commonly consult related GOSTs covering cement, aggregates, admixtures and specific test methods when applying this standard.

Keywords

fly-ash, thermal power plant ash, pulverized ash, pozzolanic additive, concrete additive, GOST 25818-2017, technical conditions, sampling, testing, activity index, sulphates, free CaO, soluble phosphates, radionuclide control.

FAQ

Q: What is this standard?

A: GOST 25818-2017 is an interstate standard that sets technical specifications and quality control requirements for thermal power plant fly-ashes intended for use in concretes and related cementitious products.

Q: What does it cover?

A: It covers classification, chemical and physical requirements, methods and frequencies for sampling and testing, acceptance criteria, marking/packing/storage/transport rules, and guidance on application limits (including limits for sulphates and certain contaminants). It also includes provisions for monitoring radionuclide activity and hazardous substances.

Q: Who typically uses it?

A: Concrete and cement producers, material and testing laboratories, construction designers and specifiers, ash suppliers (power plants), regulatory authorities and anyone responsible for specifying or verifying mineral additives for concrete.

Q: Is it current or superseded?

A: As of its registration and introduction, GOST 25818-2017 is an active (in-force) standard. It was designated in 2017 and introduced into force on 1 March 2018 according to official registrations. Users should verify national adoption status in their country and check for any later amendments or replacements before use.

Q: Is it part of a series?

A: It is a standalone GOST addressing fly-ashes for concretes but is commonly used together with related GOSTs that specify test methods, material properties and related construction materials standards (cement, aggregates, admixtures and test procedures).

Q: What are the key keywords?

A: Fly-ash; thermal plant fly-ash; pozzolanic additive; concrete; technical conditions; activity index; sulphates; free CaO; soluble phosphates; radionuclide activity; sampling and testing.