International codes of specifications for usage of fly ash:

USA

ASTM (West Conshohocken,PA USA)
ASTM C 618: Standard Specifation for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Portland Cement Concrete
ASTM C 311: Standard Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans for Use as a Mineral Admixture in portland cement concrete
ASTM D 5239: Standard Practice for Characterizing Fly Ash for Use in Soil Stabilization
 ASTM E 850: Standard Practice for Use of Inorganic Process Wastes as Structural Fill
ASTM E 1861: Standard Guide for Use of Coal Combustion By-products in Structural Fills
ASTM D 5370: Standard Specification for Pozzolanic Blended Materials in Construction Applications
ASTM C 1240: Standard Specification for Silica Fume for Use in Hydraulic-Cement Concrete and Mortar

IDOT (Illinois Dept. of Trans. Springfield, IL USA)

 06.01: Special Provision for Fly Ash Modified Soils
308.01: Special Provision for Fly Ash Stabilized Soil Mixture Subbase
Special Provision for Cement-Fly Ash-Aggregate Mixture (CFAM) Base Course
Special Provision for Pozzolanic Base Course, Type A
Special Provision for Use of Fly Ash in PC.C. Pavement, Base Course, Base Course Widening

AASHTO
AASHTO Standard Specifications for Transportation Materials and Methods of Sampling and Testing

EUROPEAN STANDARDS

BS 3892 Part 1 Fly Ash standard; Part 2 Fly Ash for Use as a Type II Addition
BS EN 450 European Standard for Fly Ash
BS EN 197 European Standard for Multiple Binders(fly ash,cement,silica fume)

CANADA

CAN/CSA A23.5-97 Canadian Specification for Supplementary Cementing Materials(includes fly ash)

GERMANY( Deutsches Instut fur Normung-Berlin)

DIN 1164-1 German Cement standard
DIN 1045 Reinforced Concrete Structures; Design and Construction
DIN EN 450 Fly Ash In Concrete-Definition, Demands and Quality control
ENV 206:1990 (CEN/TC 104) Beton - Eigenschaften, Herstellung, Verarbeitung und Gütenachweis
EN 445:1996 (CEN/TC 104) Einpreßmörtel für Spannglieder - Prüfverfahren
EN 446:1996 (CEN/TC 104) Einpreßmörtel für Spannglieder - Einpreßverfahren
EN 447:1996 (CEN/TC 104) Einpreßmörtel für Spannglieder - Anforderungen für üblichen Einpreßmörtel
EN 450:1994 (CEN/TC 104) Flugasche für Beton - Definitionen, Anforderungen und Güteüberwachung
EN 451-1:1994 (CEN/TC 104) Prüfverfahren für Flugasche - Teil 1: Bestimmung des freien Calciumgehalts
EN 451-2:1994 (CEN/TC 104) Prüfverfahren für Flugasche - Teil 2: Bestimmung der Feinheit durch Naßsiebung

NETHERLANDS

NEN 3550 Dutch cement standard

UNITED KINGDOM(British Standards Institution- London)

B.S. 3892 PFA as a separate constituent in OPC
B.S. 6588 Blended cement containing PFA
B.S. 6610 Pozzolanic pulverised fuel ash cement

AUSTRALIA

 Flyash -AS 3582.1-1991
A.S. 1129 Fly Ash Specification