ASTM_C_1791_-_16.pdf

Designation:C179116Standard Guide forReduction of Efflorescence Potential in New Unit PavementSystems1This standard is issued under the fixed designation C1791;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This guide covers methods for reducing efflorescencepotential in new unit pavement systems.1.2 The values stated in inch-pound units are to be regardedas the standard.The SI units given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:C67 Test Methods for Sampling and Testing Brick andStructural Clay TileC270 Specification for Mortar for Unit MasonryC1180 Terminology of Mortar and Grout for Unit MasonryC1232 Terminology of Masonry3.Terminology3.1 Definitions:3.1.1 Terminology defined in Terminologies C1180 andC1232 shall apply in this guide.3.2 Definitions of Terms Specific to This Standard:3.2.1 cryptoflorescence,na crystalline deposit of water-soluble compounds in the pores of unit pavement systemmaterials.3.2.2 efflorescence,na crystalline deposit,usually white,of water-soluble compounds on the surface of a unit pavementsystem.3.2.2.1 DiscussionWhilenotconsideredtobeefflorescence,stains produced by acid-soluble vanadium com-pounds in clay masonry are usually yellow or green;and stainsproduced by acid-soluble manganese compounds are usuallybrown or gray.3.2.3 jointing material,nmortar,aggregate,sealant,orother materials used between paver units.3.2.4 unit pavement system,na system consisting of edgerestraint,wearing course of discrete clay or concrete pavers,setting bed,jointing material,base or sub-base,or combinationthereof,and appropriate drainage elements.3.2.4.1 DiscussionFlexible pavement is a unit pavementsystem whose wearing course consists of discrete clay orconcrete pavers on an aggregate base,an aggregate basestabilized with asphalt or cement,or asphalt pavement.3.2.4.2 DiscussionRigid pavement is a unit pavementsystem whose surface wearing course consists of discrete clayor concrete units on a rigid base such as concrete.4.Significance and Use4.1 This guide provides information that,if implemented,will reduce efflorescence potential in new unit pavementsystems.However,its implementation will not always com-pletely prevent efflorescence.4.2 This guide may be augmented by related informationcontained in the appendixes of Specification C270,the addi-tional material listed in Appendix X1 in this standard,andother publications.5.Principles of Efflorescence5.1 Efflorescence is directly related to the quantity ofwater-soluble compounds within,or exposed to,a unit pave-ment system;and to the quantity of water exposed to thesecompounds.Water-soluble compounds or water causing efflo-rescence may be from adjacent surfaces or beneath the pave-ment system:for example,fertilizer in runoff from adjacentflower beds or lawns;ground water evaporating through thewearing course;water-soluble compounds leaching out ofcrushed recycled concrete used in pavement bases;and waterfrom sprinkler systems and roofs.Since neither water norwater-soluble compounds can be completely eliminated fromunit pavement systems,the potential for efflorescence isreduced by reducing water-soluble compounds and waterretained within the unit pavement system.1This test method is under the jurisdiction of ASTM Committee C15 onManufactured Masonry Units and is the direct responsibility of SubcommitteeC15.05 on Masonry Assemblies.Current edition approved Aug.1,2016.Published August 2016.Originallyapproved in 2014.Last previous edition approved in 2015 as C1791 15.DOI:10.1520/C1791-16.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 Water can penetrate through joints in the surface of unitpavement systems.It can penetrate voids in the mortar joints orthe interface between the paver unit and jointing material.5.3 If a significant amount of water penetrates a unitpavement system,the water will dissolve water-soluble com-pounds that may exist in the paver units,mortar components,grout,setting bed,concrete slab,admixtures or other secondarysources,and may deposit them on the exterior surface of theunit pavement system when it migrates to the surface andthrough evaporation.The presence of a concrete slab belowsand setting beds in unit pavement system allows water toremain on top of the slab where it can more readily dissolvewater-soluble compounds in the conc