2020 cttp Center er fo for Training ng Transpor ortation on Profes fessiona onals Soils Testi ting ng Techn hnici cian Course Overview ♦ Termi rminolo ology ♦ Atterber erberg g Limits its • LL, PL, PI ♦ Soil il Class ssification ification ♦ Moistur isture e Density sity ♦ Samplin ling Rela lati tions nships hips ♦ Soil il Prepar aratio ation • Standar ndard d Proc octor or ♦ Moistu isture e Conten ent • Modif ified ied Proctor or • Oven ♦ Compac pactio ion • Speedy dy Moisture ture Tester er • Nuclear lear Densit ity Gauge ge ♦ A R DO DOT Speci ecific icatio ations Introduction 4 1
2020 Test Day ♦ Writt itten en Exam am ♦ Performance mance Exam • ≈ 60 Questions • 4 Exam Station ations • Closed ed Book Exam ~ Liquid id Limit it • 2 Hour ~ Plastic Limit it r Time e Limit it ~ Proctor or • 70 % Overall erall Required ired ~ Nuclear ear Densit ity Gauge to Pass Exam • 2 Attem empts ts Allo lowed ed to ♦ Resu sults ts Pass Each h Stati ation on • www.ctt ttp.org .org • Lett tter er & Certi tific ficat ate Introduction 5 Unit Conversions ♦ Conver ert t 15 lb to grams ams ♦ Weight ght / Mass • 1 ton 2000 lb 𝟐𝟔 𝒎𝒄 𝒚 𝟓𝟔𝟒. 𝟕 𝒉 • 1 lb 453.6 .6 g = 𝟕𝟗𝟏𝟓 𝒉 𝟐 𝒎𝒄 • 1 kg 1000 g ♦ Conver ert t 6804 g t to lb 𝟐 𝒎𝒄 𝟕𝟗𝟏𝟓 𝒉 𝒚 𝟓𝟔𝟒. 𝟕 𝒉 = 𝟐𝟔 𝒎𝒄 Introduction 6 2
2020 Terminology ♦ Testin ting ♦ Soil il • Grain ain Size influ luen ences es • Natura turall lly occurrin rring g the stabilit ility and uncons onsolida olidated ed rock k maxim imum um load d bearing ring partic icles les, , organic anic capacit ity of a soil matter er, , water er, , and air • Behavior vior Charac racter eristic istics predic ict how ow a soil l will behave e to chang nges es in moisture ture • Densit ity optim imize izes the enginee ineering ring properti ties es of the soil for r the inten ended ed applic icati ation on Introduction 7 Terminology ♦ Air r Dried ied ♦ Oven en Dried ied • Dried at ≤ 140 °F • Dried F ied to a constant tant (60°C) C) mass at a temperature erature of 230 ± 9 9 °F ~ Chemic ically ally bound nd (110 ± 5 5 °C) C) moisture e is stil ill l present ent in the soil ~ No moistur ure e is present ent ~ Moisture Content ≠ 0 in the soil l sample le ~ Moisture e Content nt = 0 Introduction 8 3
2020 Sampling Soils A R DOT 30 Sampling 9 ♦ Back hoe, , auger, , post hole le Apparatus digger er, , shovel el ♦ Samp mple e Contain ainer ers • Should prevent ent the loss of fines es and moistur ture ~ Seala lable le plastic ic container ers ~ Heavy vy doubled led pape per bags are ok if mois isture e is not to be main intain ined ed ~ Unlin lined ed cloth oth or open en we weave bags should ld not be used ed Sampling 10 4
2020 Sampling ♦ Sample e Numbers • Areas eas must t be enclo losed sed by at least t three ee sampl mples es ~ Risk fa factor or of fa failure ure Look for changes ges in soil types es, color or, or tex textu ture ~ Unif ifor ormity mity of soil • Typic ical Spac acin ing ~ Highway: 200’ – 2000’ ~ Borrow Pits: 100’ – 400’ ~ Earth Dams: 50’ – 150’ Sampling 11 Documentation ♦ Sample le Locatio ation ♦ Soil il Samp mples les • Refere • Test rence nce landmarks dmarks t Pit t or Boring ng # • Material ~ Fence e Posts erial Classif ificati ation on ~ Buildin ings gs / Ro Roads ~ Type of mater erial ial • Sketc etch ~ Color and classifi ificat ation on • Layer er Depths ths ~ Start and end depth h of each h layer • Commen ents ts ~ Water table le levels ls ~ Ro Rock outcrop ops Sampling 12 5
2020 Test Pit Sampling 13 Boring Sampling 14 6
2020 Dry Preparation of Disturbed Soil… Samples for Test AASHTO R 58 Dry Preparation 15 Apparatus ♦ Dryin ing Apparatus aratus ♦ Pulveri erizin ing Apparatus aratus • Fan, • Mortar , heat t lamp, oven tar & rubber er - covered red pestle le ♦ Sieves es • 2”, ¾”, # 4, # 10, # 40 • Addit itional ional sizes es as needed ed by specif ific ic test t • Pow Power er equip ipmen ent t with rubber er - covered red roller lers Indi divid idua ual l grain in sizes s may not ot be redu duced ed in size ! Dry Preparation 16 7
2020 Procedure ♦ Air dry mater erial ial ♦ Pulver erize ize mater erial ial • ≤ 140 °F ret etain ained ed on scree reen • Rescreen reen the material erial ♦ Redu duce samp mple le • Repeat at until il all soil • Split it or Quarter er partic icles les are separat rated ed ♦ Selec ect t appropria opriate e ♦ Comb mbine e and mix all sieve e accor ordi ding to test t mater erial ial passin sing the proc ocedu dure e to be specifie ified d screen en performed med Use AASHT HTO R 74 (Wet et-Prep) p) fo for hard-to to- ♦ Proc ocess ess soil il over er proc ocess ss soils, s, or soils s which need d to maintain ain specified ified sieve their natural al moisture e conten ents Dry Preparation 17 Test Method for Moisture Content of Soils… A R DOT 348 AASHTO T 265 Moisture Content 18 8
2020 ♦ A R DO DOT Spec ecif ificatio ications Field Testing • Oven Drying ing ~ Most Accurat ate ~ Slow ow Re Result lts • Speedy dy Moisture ture ~ Limit ited ed to finer graine ned soils ls ~ Quick Re Result ults ~ No licens nse required ed • Nu Nuclear lear Density ity Gauge ge ~ Accurac acy may fluctuat uate e based ed on surround undin ing g condit itions ions ~ Quick Re Result ults ~ Nuclear ear licens ense required ed Moisture Content 19 Apparatus (Oven Drying) ♦ Scales ales • 0.1 % of sample le wt. ~ 10 g → 0.01 g ~ 100 g → 0.1 g ~ 500 g → 0.5 g ♦ Oven en • 230 230 ± 9 9 °F ♦ Moistu isture e Tins • Corros osion ion Resistant tant • Close-fit itting ing Lids Moisture Content 20 9
2020 Procedure ♦ Rec ecor ord d number ber and ♦ Dry samp mple le at 230 °F F tare re weight ht of tin to a con onstan stant t mass • Remove e lid ♦ Place “wet soil” into tin ♦ Remo move e tin from m oven en • Cover r with h lid and cool ♦ Rec ecor ord d weight ht of • Cover r with h lid “Wet Soil + Tare” ♦ Rec ecord d weight ight of “Dry Soil + Tare” Moisture Content 21 Calculation 𝑵𝑫 = (𝑿 − 𝑬) 𝒚 𝟐𝟏𝟏 % 𝑬 W = wet et weigh ght t of soil D = dry y weigh ght t of soil il ♦ Repor ort t moistu isture re con onten ent t to the nearest rest 0.1 1 % Moisture Content 22 10
2020 Calculation ♦ Det eter ermin mine e the moistu isture e conten ent t of the soil Wet t Wt Wt + Tare 30.62 g 𝑵𝑫 = (𝑿 − 𝑬) Dry Wt Wt + Tare 29.55 g 𝒚 𝟐𝟏𝟏% 𝑬 Tare e Weight ight 18.76 g Wet Soil = 30.62 – 18.76 = 11.86 Dry Soil = 29.55 – 18.76 = 10.79 𝑵𝑫 = (𝟐𝟐. 𝟗𝟕 − 𝟐𝟏. 𝟖𝟘) 𝒚 𝟐𝟏𝟏% = 𝟐. 𝟏𝟖 𝟐𝟏. 𝟖𝟘 𝒚 𝟐𝟏𝟏 % = 𝟘. 𝟘𝟑 % 𝟐𝟏. 𝟖𝟘 9.9 % Moisture Content 23 Calculation ♦ Det eter ermin ine e the moistu isture re conten ent t of the soil Wet t Wt Wt + Tare 44.7 .75 g Dry Wt Wt + Tare 40.33 g Tare e Weight ight 13.00 g Moisture Content 24 11
2020 Special Cases ♦ Soil il contai tainin ing ♦ Solutio lutions ns minerals erals whic ich h have e loosely osely bound d wa water er • Oven dry at ≈ 140 °F from om hydra dration tion • Gypsum um • Use va vacuu uum desic iccati ation on at ♦ Soil il contai tainin ing ≈ 10 mm Hg at a temperature erature of signif ifican icant t amoun ounts ts of ≥ 73 °F organ anic ic mater erial ials Moisture Content 26 Sieve Analysis of Soils AASHTO T 11 AASHTO T 27 Sieve Analysis 27 12
2020 Sieve Analysis of Soils ♦ Det eter ermin mines es the grain in ♦ Differenc ences es size e distri tribution tion of • Soil l Sieve Sizes es soils ls ~ 2”, 1½”, 1”, ¾”, 3/8”, #4, #10, #40, #200 • Washing ♦ Used d for: ing • Soil ~ Use we wettin ing g agent nt if l Classif ific icati ation on necess essar ary • Complianc liance ~ Allow ow ex extra a soak time ~ ARDOT Specif ific icat ations ions • Embankment • Plating Materials • Select Materials Sieve Analysis 28 ♦ Liquid quid State Introduction • Flow ows and chang nges es shape e easily ly ♦ Atterberg berg limit its s ♦ Plastic stic Stat ate -- Liquid -- id Limit it -- -- charac acteriz ize • Moldab dable le ity how ow a soil will l Plasticit Index and retains tains behave e with shape changes ges in moistur ture e ♦ Solid lid State -- -- Plastic ic Limit it -- -- content ents • Breaks aks • Liquid uid Limit mit rather her than n • Plastic ic Limit mit chang nge e • Plasti sticit ity y Index shape Atterberg Limits 30 13
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