engineered soils for sports field constructionssturf.lib.msu.edu/article/2001apr32.pdfengineered...

Engineered Soils forSports Field Constructions

by Michael DePew and Stephen Guise

M any types of root zone con-structions exist for all levelsof play on sports turf areas

from recreational fields to professionalstadiums to thoroughbred racetracksThe expected level of use and subse-quent maintenance resources andmanagement requirements shoulddrive the decision as to the type of rootzone system constructed at a givensite Levels of use can be categorizedinto two types frequency of use andintensity of use These levels of useand the performance expectations ofthe installation determine to a largeextent the soil engineering principalsthat are most applicable to the fieldsdesign

Levels of useFrequency of use (use-frequency)

can be evaluated as either total hoursof play in a given cycle or by the hoursof plays clustered at certain time inter-vals within a cycle For example twofields can each have 20 hours of use ina seven-day cycle but if the one fieldhas a high proportion of its usage time(say 14 of the 20 hours) clusteredaround day 6 and 7 of the cycle it willhave a different type of wear than ifthe field is used in equal time incre-ments spread across each day of thecycle

Intensity of use (use-intensity) fac-tors include the level of competitivenessand number of hours per event andtherefore total stress level per event onthe field Larger more competitive ath-letes apply higher stress loads on aplaying surface However lower com-petitive levels will tend to have wearpatterns clustered around the center ofthe field while higher competitive levelswill have wear stresses more widelydistributed across the field The rela-tive importance to a facility of use-fre-quency versus use- intensity is anextremely important factor in root zonesystem design

Soil Design TypesSports turf root zone constructions

may be placed into four basic cate-gories soil-based sand-modifiedsand-amended or sand-based fieldsEach type of field design has its ownparticular strengths and subsequentlimitations

SOIL-BASED DESIGNSSoil-based fields primarily refer to

field constructions from native-typesoil material This type of native soilmaterial can refer to either on-site topsoil or imported soil Generallyspeaking we think of soil-based fieldsas loamy textures and finer Sandsand loamy sands while they may benatural native soils are generallythought of as sand-based or sand-amended fields

Soil root zones

will deteriorate

rapidly if played

on in conditions

of excessive soil

moisture levels

In general soil-based fields mayhave certain advantages over othertypes of constructions Soil-basedfields have higher water and nutrientholding capacity and generally havehigher use-frequency capacities Soil-based fields generally provide a bettergrowth media than other field designtypes However the effect of com-paction can rapidly rank these fielddesigns inferior to the other field

design types

Soil-based fields have the greatestpotential for high soil shear strengthcharacteristics if maintained in anon-compacted well drained and wellaerated state In an uncompactedstate these fields will provide forexcellent traction and playabilityThey are however the type of rootzone system most prone to com-paction especially when their usecapacity is exceeded in terms ofeither frequency or intensity Soil-based constructions also have thegreatest limitations to play over wideranging moisture and environmentalconditions Soil root zones will dete-riorate rapidly if played on in condi-tions of excessive soil moisture levels

At high soil moisture contents theplasticity characteristics of the soilcan be nullified as the soil behavesmore like a liquid When this occurssoil material often is pumped to thesurface and the entire field is proneto surface rutting and trackingUnder these conditions the naturalsoil structural integrity is rapidlylost and cannot easily be restored Inmost cases it can never be restoredwithout taking the field out of playand performing extensive renovation

SAND-MODIFIED ANDSAND-AMENDED DESIGNS

Sand-modified root zones are thosenative soil-based fields that havebeen modified on-site by additions ofsand Sand is normally addedthrough topdressing programs aloneor in combination with aeration prac-tices As sand is added to manynative or plastic-type soil materialsthe sand will increase the internalfriction of the soil somewhat(decrease deformability) As moresand is added the compaction resis-tance of the root zone will increasedue to increasing internal frictionHowever sand additions alsodecrease the plasticity of soil materi-

32 April 2001 sportsTURF bull httpwwwsportsturfonlinecom

als If a soil does not contain a highenough sand proportion the result-ing rootzone will neither exhibit sig-nificant compaction resistance nordesireable plasticity characteristicsCaution must be exercised with theuse of a sand modification programas the end result could make a prob-lem worse rather than better Ofcourse sand selection greatlyimpacts the resulting soil propertiesas well

Enhancement of soil aeration anddrainage would not be expected as adirect effect of sand additions Theenhanced aeration and drainagecharacteristics of a sand-modifiedsystem would be due to a longer peri-od of time that the soil remains non-compacted Actual increases in aera-tion and drainage characteristicswould not be expected until sand pro-portions exceed a threshold propor-tion Threshold proportions of sandand soil mixtures typically require 60percent or more sand on a volumebasis Significant increases indrainage and aeration properties arenot typically observed until sand vol-ume proportions exceed 80 percent ormore depending upon the particlesize distribution of the sand and soilcomponents

Sand-amended root zones arethose that have native soils mixedwith sand during complete renovationor new field construction To ensureproper and thorough mixing of thesand and soil components off-sitemixing and blending with a screw ordrum type self-contained blendershould be practiced over an on-siteblending process that utilizes roto-tilling or rotary cultivation Newblending equipment such as the Net-avator blender (distributed by Multi-Use Designs Inc) has slow speedreverse-tine tilling and shows goodpromise as a method for acceptableon-site blending of soils

The performance of these types ofconstructions vary widely dependingupon the various proportions of sandand soil as well as the relative parti-cle size distribution of each of thecomponents The ratio of silt to clayand the mineralogy of the silt andclay fractions is an important designconsideration Organic componentsare sometime included as part of themixture Adequate performance ofthese constructions require consider-able soil science expertise to ensure

long-term success An experiencedand qualified sports turf agronomistshould be consulted when consideringthese design specifications

SAND-BASED DESIGNSSand-based root zone construc-

tions can be expensive but may pro-vide a greater performance potentialAs such they often receive the mostrecognition as a desirable athleticfield construction Sand-based rootzones do generally have a much high-er use-intensity than do other types ofroot zone constructions Sand-basedsystems however because of theirgranular make-up and lack of plastic-ity do not necessarily have the high-est use-frequency While a soil-basedroot zone system can have dramati-cally higher use-frequency over sand-based systems a sand-based systemwill perform over widely ranging andhighly variable weather conditionsThis includes live play even undersevere and intense rainfall events Asoil-based system would deterioraterapidly under the same severe condi-tions

A well designed and constructedsand-based fieldwill provide aroot zone thathas high aera-tion anddrainage ratesThe higher ratesof aeration anddrainage insands is due to agreater propor-tion of macrop-orosity Thishigh macroporos-ity also results inreduced microp-orosity and like-wise these rootzones havereduced moistureretention andtherefore if notmanaged correct-ly can bedroughty

S a n d - b a s eroot zones arecommonly com-posed of lowreactivity silicateminerals such asquartz Thisinherent lowreactivity results

in a material that has a low bufferingcapacity This low buffering capacityis exhibited both as low cationexchange capacity (CEC) and a soilsystem that is subject to vast andrapid soil chemical changes Tocounter these effects an organicamendment is often added It shouldbe noted however that organic con-stituents vary widely as to their phys-ical and chemical characteristics andtherefore the performance character-istics of the resulting blend can varywidely

To counter the effects of inherentdroughtiness in sands sand-basedsystems with an underlying layer ofgravel have been employed The(EUSGA specifications for puttinggreen construction is the most widelyrecognized gravel underdrain designA gravel (coarser) layer underlying asand (finer) layer will impededrainage under non-ponded (unsatu-rated) conditions This impedance ofwater movement effectively increasesthe water holding capacity of the rootzone The larger the contrast in pore-sizes between the coarser layer andthe overlying finer textured layer the

Note

AppreciationWe appreciate our customers

distributors and businesspartners that allow Diamond Pro

to participate in theGreat Game of Baseball

Best Wishes on the Season

wwwdiamondproxom

Circle 119 on Inquiry Card

sportsTURF bull httpwwwsportsturfonlinecom April 2001 33

more water that the root zone willretain The danger then is having toolarge of particle size contrast or tooshallow of root zone depth such thatmuch or nearly all of the root zonestays excessively wet

Excessive wetness within therootzone profile may result in theinducement of anaerobic andreduced conditions in the profile andcreate an environment inconduciveto turf growth health and develop-ment One signal of excessively wetconditions in a sand-based system isthe production of excessive thatch insod-forming grasses or elevatedcrowns in bunch-type grasses Whileextensive and often drastic culturaltechniques are employed to reducethatch under these conditions prop-er aeration and drainage in the rootzone would eliminate the productionof the excessive thatch Black layeris another phenomana that can occurin a sand-based rootzone design dueto excessive moisture The excessivemoisture leading to black layer for-mation can be due to either an oversaturated gravel underdrain designor from layer features that can devel-

To ensure thatexcessively wetand reducedsand-based rootzones are notconstructedcareful designand constructionmust beemployedop over time in poorlyconstructeddesigned and or poorlymaintained sand-based fields

Soil Conditioners and Infield Mixes

Products to aid the professional groundskeeper withfield construction renovation and maintenance

bull Bulk HydRockstrade Rotary Kiln ProducedLightweight Soil ConditionerBulk Pre-Blended Infield Mix wHydRockstradeBulk Mound amp Batters Box MixBulk SlateScapetrade Warning Track MixBulk Erthfoodtrade Compost and Topdressing SandAgzyme Enzyme Field ConditionerField Maintenance EquipmentLaser Grading and Turf Management

Highest Quality and Competively Priced

Rock amp Earth Technologies Inc1-800-752-8313

Sports Field Division Rockmart Georgia404-7- 5-5881


To ensure thatexcessively wetand reducedsand-based rootzones are notc o n s t r u c t e d careful designand constructionmethodologiesmust beemployed Whilemany root zonec o n s t r u c t i o nspec i f i ca t ionmethods havebeen used andpromoted a newgeneration ofsand-based rootzone design spec-ifications arenow available fornot only sand-based but alsosand-amendedsand-modifiedand soil-basedconstructionsEven the bestsand-based con-structions of thepast have experi-enced poor per-

formance following a period of rela-tively high superior performanceThis period of good performance fol-lowing construction is often termedthe honeymoon period Followingthis honeymoon period the perfor-mance can rapidly and drasticallydeteriorate The length of thesehoneymoon periods is highly vari-able but often last three to fiveyears but may be less Remedialefforts on these facilities oftenresults in extensive renovation orcomplete reconstruction To avoidthese excessive costs and practicesproper root zone design along withtesting and QC management duringconstruction should be employed bya qualified sports turf agronomist

ROOT ZONE AMENDMENTS FORSAND-BASED CONSTRUSTIONS

Many amendments have been usedand marketed to improve the perfor-mance of the different types of rootzone constructions These amend-ments vary from natural and syntheticorganics to mined inorganic mineralsand various other synthetic materialsIn the past seven to eight years manynew synthetic materials have beenintroduced to improve the physical andmechanical performance of sports turfroot zones

A sand-based field offers thegreatest flexibility in terms of provid-ing an all weather playing surfaceThe down side to these systems isthat poor soil plasticity characteris-tics may create situations wherethese constructions cannot meetoverall performance expectationsThe use of synthetic fiber reinforce-ment may significantly increase themechanical stability of sand-basedconstructions Fibers grids meshesand fabrics have all been utilized asan aid in increasing the stability ofsand-based constructions Whilemany of these materials do providefor greater stability they may alsoserve simply to stabilize the sandonce it becomes compacted Fabriclayers may also increase stabilitysomewhat but also create a potentialproblem by introducing a (Eshearplane A shear plane can be detri-mental because while overall stabili-ty is increased when failure of sheardoes occur the failure event can besudden and severe In other wordsthe field may be more stable overallbut when playing forces exceed thestability limits the field can give way


rapidly with severe divoting Thegreatest potential benefit with syn-thetic materials for root zone stabi-lization has been derived from thosesynthetic products that provide adynamic interlock system Dynamicinterlock spreads the applied forcesover a larger volume of the soil pro-file Dynamic interlock (as opposedto static interlock) also provides acharacteristic CErebound effect inthat the interlocked soil complexattmepts to resume its original (lesscompacted) state following removal ofthe loading force

Other amendments are promotedfor their effects at modifying soilmoisture and soil chemical proper-ties Various internally porousamendments have been utilized toimprove moisture relations withinsand-based rootzones These inter-nally porous materials include suchthings as diatomaceous earth andcalcinedvitrified clay mineralsAmendments utilized to modify chem-ical characteristics of sand-based con-structions include small additions of

soil andor organic matter (such aspeat or various composts) Of coursethese materials also affect the soilretention properties of the soil profileas well Zeolitic minerals have alsobeen used to improve the nutrientretention properties of sand-basedrootzones The mechanical stabilityof amending materials should be con-sidered before employing them in asand-based root zone constructionMany materials have the potential offracturing into finer sizes within theprofile under traffic stress Oncefractured into smaller particlesthese materials can be prone tomigration and subsequent detrimen-tal layering effects

CONCLUSIONWhatever root zone design specifi-

cation method is employed in rootzone construction and establishmenta qualified sports turf agronomist canincrease the likelihood of a successfuland satisfactory sports turf installa-tion The design and type of sportsturf root zone construction should bedetermined by the type of competition

that is expected on the field the fre-quency of use the maintenanceexpertise and maintenance budgetexpected and the turf quality andplayability expectations of the ownerand user(s)

Stephen Guise is a Past Presidentof the Sports Turf ManagersAssociation director of business devel-opment for Marina LandscapePresident of Guise and Associates (asports turf consulting company) andthe Vice-Chairman of the ASTM F08-64 subcommittee for Natural TurfPlaying Fields

Michael DePew is an agronomist soilscientist working for EnvironmentalTurf Solutions Inc ofPineland FloridaMichael works extensively with sportsfield design and also specializes in saltwater irrigated golf sports and land-scape developments Michael is Chair ofthe Sports Turf Managers AssociationTechnical Standards Committee andalso serves on the ASTM F08-64 sub-committee for Natural Turf PlayingFields

GET IN M SWIMIf you know a child with

muscular dystrophy who canbenefit from a special getaway

tell him or her aboutMDA summer campsTheyre fun and free

Muscular Dystrophy AssociationJerry Lewis National Chairman

1-800-572-1717 bull wwwmdausaorg

People Help MDA Because MDA Helps People


als If a soil does not contain a highenough sand proportion the result-ing rootzone will neither exhibit sig-nificant compaction resistance nordesireable plasticity characteristicsCaution must be exercised with theuse of a sand modification programas the end result could make a prob-lem worse rather than better Ofcourse sand selection greatlyimpacts the resulting soil propertiesas well

Enhancement of soil aeration anddrainage would not be expected as adirect effect of sand additions Theenhanced aeration and drainagecharacteristics of a sand-modifiedsystem would be due to a longer peri-od of time that the soil remains non-compacted Actual increases in aera-tion and drainage characteristicswould not be expected until sand pro-portions exceed a threshold propor-tion Threshold proportions of sandand soil mixtures typically require 60percent or more sand on a volumebasis Significant increases indrainage and aeration properties arenot typically observed until sand vol-ume proportions exceed 80 percent ormore depending upon the particlesize distribution of the sand and soilcomponents

Sand-amended root zones arethose that have native soils mixedwith sand during complete renovationor new field construction To ensureproper and thorough mixing of thesand and soil components off-sitemixing and blending with a screw ordrum type self-contained blendershould be practiced over an on-siteblending process that utilizes roto-tilling or rotary cultivation Newblending equipment such as the Net-avator blender (distributed by Multi-Use Designs Inc) has slow speedreverse-tine tilling and shows goodpromise as a method for acceptableon-site blending of soils

The performance of these types ofconstructions vary widely dependingupon the various proportions of sandand soil as well as the relative parti-cle size distribution of each of thecomponents The ratio of silt to clayand the mineralogy of the silt andclay fractions is an important designconsideration Organic componentsare sometime included as part of themixture Adequate performance ofthese constructions require consider-able soil science expertise to ensure

long-term success An experiencedand qualified sports turf agronomistshould be consulted when consideringthese design specifications

SAND-BASED DESIGNSSand-based root zone construc-

tions can be expensive but may pro-vide a greater performance potentialAs such they often receive the mostrecognition as a desirable athleticfield construction Sand-based rootzones do generally have a much high-er use-intensity than do other types ofroot zone constructions Sand-basedsystems however because of theirgranular make-up and lack of plastic-ity do not necessarily have the high-est use-frequency While a soil-basedroot zone system can have dramati-cally higher use-frequency over sand-based systems a sand-based systemwill perform over widely ranging andhighly variable weather conditionsThis includes live play even undersevere and intense rainfall events Asoil-based system would deterioraterapidly under the same severe condi-tions

A well designed and constructedsand-based fieldwill provide aroot zone thathas high aera-tion anddrainage ratesThe higher ratesof aeration anddrainage insands is due to agreater propor-tion of macrop-orosity Thishigh macroporos-ity also results inreduced microp-orosity and like-wise these rootzones havereduced moistureretention andtherefore if notmanaged correct-ly can bedroughty

S a n d - b a s eroot zones arecommonly com-posed of lowreactivity silicateminerals such asquartz Thisinherent lowreactivity results

in a material that has a low bufferingcapacity This low buffering capacityis exhibited both as low cationexchange capacity (CEC) and a soilsystem that is subject to vast andrapid soil chemical changes Tocounter these effects an organicamendment is often added It shouldbe noted however that organic con-stituents vary widely as to their phys-ical and chemical characteristics andtherefore the performance character-istics of the resulting blend can varywidely

To counter the effects of inherentdroughtiness in sands sand-basedsystems with an underlying layer ofgravel have been employed The(EUSGA specifications for puttinggreen construction is the most widelyrecognized gravel underdrain designA gravel (coarser) layer underlying asand (finer) layer will impededrainage under non-ponded (unsatu-rated) conditions This impedance ofwater movement effectively increasesthe water holding capacity of the rootzone The larger the contrast in pore-sizes between the coarser layer andthe overlying finer textured layer the

Note

AppreciationWe appreciate our customers

distributors and businesspartners that allow Diamond Pro

to participate in theGreat Game of Baseball

Best Wishes on the Season

wwwdiamondproxom


































engineered soils for sports field constructionssturf.lib.msu.edu/article/2001apr32.pdfengineered...

Documents