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Home My WebLink AboutBID - 5927 TRILBY ROAD AND ZIEGLER ROAD IMPROVEMENT PROJSUBGRADE INVESTIGATION AND PAVEMENT DESIGN FOR STREETS IN THE VICINITY OF KINARD JUNIOR HIGH SCHOOL FORT COLLINS, COLORADO Prepared for: CITY OF FORT COLLINS STREET OVERSIZING DEPARTMENT 281 North College Avenue P. O. Box 580 Fort Collins, Colorado 80521 Attention: Ms. Eileen Bayens Project No. FC03508-135 June 15, 2005 4001 Automation Way I Unit 2011 Fort Collins, Colorado 80525 Telephone:970-206-9455 Fax:970-206-9441 Installation of a geotextile fabric (Mirafi 500X or equal) between the subgrade and the base course could be used if the fly ash stabilized subgrade is not. Such an application of fabric increases the performance of the pavement because it prevents the subgrade and base course from mixing which can happen over the design life of the pavement section, especially In areas where higher volumes of automobile traffic are expected. If subgrade stabilization due to soft or loose soils is required, overexcavation and replacement with coarse, granular soil such as pit run gravel, use of geotextiles or geogrids, or chemical stabilization such as fly ash typically perform well In soil environments similar to those we encountered at this site. Chemical stabilization techniques have weather and temperature limitations that should be considered. PAVEMENT MATERIALS Material properties and construction criteria for the pavement alternatives are provided below. These criteria were developed from analysis of the field and laboratory data, our experience and City of Fort Collins requirements. If the materials cannot meet these recommendations, then the pavement design should be reevaluated based upon available materials. All materials and construction requirements of the City of Fort Collins should be followed. All materials planned for construction should be submitted and the applicable laboratory tests performed to verify compliance with the specifications (see Appendix C). Asphaltic Concrete (AC) 1. Hot mix asphalt should be composed of a mixture of aggregate, filler, hydrated lime, and asphalt cement. Some mixes may require polymer modified asphalt cement, or make use of reclaimed asphalt pavement (RAP). A job mix design is recommended and periodic checks on the job site should be made to verify compliance with specifications. CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, 8 ZEIGLER ROAD WIDENING AND TRILBY ROAD OIL I T PROJECT NO. FC03508-135 S-0 01508.000113W. Report 11FC03508.135.rptdoc T 2. Hot mix asphalt should be relatively Impermeable to moisture and should be designed with crushed aggregates that have a minimum of 80% of the aggregate retained on the No. 4 sieve with two mechanically fractured faces. 3. Gradations that approach the maximum density line (within 5% between the No. 4 and 50 sieve) should be avoided. A gradation with a nominal maximum size of 3/4 or 1/2 inches developed on the fine side of the maximum density line should be used. 4. Total void content, voids in the mineral aggregate (VMA) and voids filled should be considered in the selection of the optimum asphalt cement content. The optimum asphalt content should be selected at a total air void content of approximately 4%. The mixture should have a minimum VMA of 14% and between 65% and 80% of voids filled. 5. Asphalt cement should meet the requirements of the Superpave Performance Graded Binders (PG). The minimum performing asphalt cement should be PG 64-22 for use along the Front Range. The use of PG 58-28 or PG 58-22 asphalt cement has been known to cause tenderness in pavements in the Front Range area and should be avoided. 6. If used, hydrated lime should be added at the rate of 1% by dry weight of the aggregate and should be included in the amount passing the No. 200 sieve. Hydrated lime for aggregate pretreatment should conform to the requirements of ASTM C 207, Type N. 7. We recommend paving only be performed when subgrade temperatures are above 40°F and air temperature is at least 40OF and rising. 8. Hot mix asphalt should not be placed at a temperature lower than 245OF for mixes containing PG 64-22 asphalt, and 290°F for mixes containing polymer modified asphalt. The breakdown compaction should be completed before the mixture temperature drops 20°F. 9. The maximum compacted lift should be 3.0 inches and joints should be staggered. No joints should be placed within wheel paths. 10. Asphalt concrete should be compacted to between 92 and 96 percent of maximum theoretical density. The surface shall be sealed with a finish roller prior to the mix cooling to 1850F. 11. Placement and compaction of hot mix asphalt should be observed and tested by a representative of our firm. Placement should not commence until the subgrade is properly prepared (or stabilized), observed, and proof -rolled. CITY OF FORT COLLINS 9 OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508-135 5;1FC03505.000113517. Report 11FC03505.135.rpLdoc Mr.YY rFr Aggregate Base Course (ABC) 1. A Class 5 or 6 Colorado Department of Transportation (CDOT) specified aggregate base course should be used. A recycled concrete alternative, which meets the Class 5 or 6 designations, is also acceptable. 2. Aggregate base course should have a minimum Hveem stabilometer value of 77. Aggregate base course or recycled concrete material must be moisture stable. The change in R-value from 300 psi to 100 psi exudation pressure should be 12 points or less. 3. If used, geotextile fabric (Mirafi 500x or equivalent) should be placed over the approved subgrade within 24 hours prior to placement of aggregate base course or recycled concrete. Fabric should be rolled out longitudinally with minimum overlapped seams of 2.5 feet. No wrinkles should be permitted. 4. Aggregate base course or recycled base course should be placed in thin lifts not to exceed 8 inches, moisture treated to within 2% of optimum moisture content, and compacted to at least 95% of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). 5. Placement and compaction of aggregate base course or recycled concrete should be observed and tested by a representative of our firm. Placement should not commence until the underlying subgrade is properly prepared and observed. Prepared Subgrade 1. Subgrade should be stripped of organic matter, scarified, moisture treated, and compacted. 2. Cohesive soils (A-6 to A-7-6) should be moisture conditioned between optimum to 2% above optimum moisture content and compacted to at least 95% of maximum standard Proctor dry density (ASTM D 698, AASHTO T 99). 3. Granular soils (A-1 to A-5) should be moisture conditioned between 2% below to 1% above optimum moisture content and compacted to at least 95% of maximum standard Proctor dry density (ASTM D 698, AASHTO T 99). 4. Final grading of the subgrade should be carefully controlled so the design cross -slope is maintained and low spots in the subgrade that could trap water are eliminated. CITY OF FORT COLLINS 1 O OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508-135 8AFC03508.000113512. Repon 17C03508.135spLdoc 0 5. Once final subgrade elevation has been reached and the subgrade compacted and observed, the area should be proof -rolled with a pneumatic tired vehicle loaded to at least 18 kips per axle. The proof -roil should be performed while moisture contents of the subgrade are still within the recommended limits. Drying of the subgrade prior to proof -roll or paving should be avoided. Areas of soft or wet subgrade should be remedied. CONSTRUCTION DETAILS The design of a pavement system is as much a function of the quality of the paving materials and construction as the support characteristics of the subgrade. The construction materials are assumed to possess sufficient quality as reflected by the strength coefficients used in the flexible pavement design calculations. These strength coefficients were developed through research and experience to simulate expected material of good quality, as explained herein. During construction careful attention should be paid to the following details: • Placement and compaction of trench backfill. • Compaction at curb lines and around manholes and water valves. • Excavation of completed pavements for utility construction and repair. • Moisture treating or stabilization of the subgrade to reduce swell potential. • Design slopes of the adjacent ground and pavement to rapidly remove water from the pavement surface. MAINTENANCE We recommend a preventive maintenance program be followed for all pavement systems to assure the design life can be realized. Choosing to defer maintenance usually results in accelerated deterioration leading to higher future maintenance costs, and/or repair (See Appendix D). CITY OF FORT COLLINS 11 OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL i T PROJECT NO. FC03508-135 $AFC03S08..000H3512. Rapdt 11FC03503.13S.rptdoc T LIMITATIONS The pavement and construction recommendations are based upon our field observation and testing, minimum traffic levels, and design criteria required by the City of Fort Collins and the AASHTO design methods. The design procedures were formulated to provide sections with adequate structural strength. Routine maintenance, such as seating and repair of cracks, is necessary to achieve the long-term life of a pavement system. If the design and construction recommendations cannot be followed, or anticipated traffic loads change considerably, we should be contacted to review the recommendations. We believe the geotechnical services for this project were performed in a manner consistent with that level of care and skill ordinarily used by members of the profession in the locality of the project. No warranty, express or implied, is made. If we can be of further service in discussing the contents of this report, or in the analyses of the proposed pavement systems from a geotechnical point of view, please call. CTL I THOMPSON, INC. John J. Boutden, EIT Staff Engineer Reviewed by: Frank J. Holliday, PE, CCE Senior Consultant JJB:FJH:bly (6 copies sent) CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, 12 ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03500435 S.IFC03500.000113517. Report 11FC03508.13S.rp1.d= SCALE: NOT TO SCALE SHAL�M • TH-10 T LEGEND: POND DRIVE TH-3 TH-Z TH-1 TH-6 TH-5 TH-7 TRILBY TH-8 ROAD TH-1 INDICATES APPROXIMATE APPROXIMATE LOCATION OF EXPLORATORY BORINGS CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD, TRILBY ROAD CTL I T PROJECT NO. FC03508-135 VICINITY MAP (FORT COLLINS AREA) NOT TO SCALE 0 Q O w J O w_ N I1119:�. Locations of Exploratory Borings IF FIGURE 1 OLD LEGACY ZEIGLER ROAD _TRILBY ROAD DRIVE TH3 TH2 THI TH4 TH5 TH6 TH7 THE TH9 TH10 0 -.,7 -.7 71. 0 1 ? o o' 2 1W12 12J12 12/12 12/12 18/12 v 0113112 ]11112 ]W12 ]6112 ]11112 2 3 .] 3 4 A 8112 W12 ]&12 it: ]3112 ]&12 -.]7/12 ]4tl2 ]V12 ]W12 W12 4 5 Z, 10 6 10Y =10 6 0 o 7 1 7 ? 8 'o V v _V V 8 9 IW12 M12 U12 2112 2112 10 .1 6/12 — 1/12 23112 16/12 9 10 10 11 11 12 12 LEGEND: SAND, CLAYEY, LOOSE TO MEDIUM DENSE, MOIST TO WET, BROWN TO DARK BROWN (SC) DRIVE SAMPLE. THE SYMBOL 17112 INDICATES 12 SLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5—INCH O.D.SAMPLER 12 INCHES. WATER LEVEL MEASURED AT TIME OF DRILLING. NOTES: 1. THE BORINGS WERE MILLED ON MY 24,2005, USING 6-INCH DIAMETER CONTINUOUS —FLIGHT AUGER AND A TRUCK -MOUNTED DRILL RIG. 2, THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. =::4-aa man SUMMARY LOGS OF EXPLORATORY BORINGS Mo LEencY carve. wL DE MC. FIGURE 2 CTLJTMpJECTHOiC06C6IM I HYDROMETER ANALYSIS I SIEVE ANALYSIS 25 HR. 714R. TIME READINGS V.S.STANDARD SERIES CLEAR SQUARE OPENMS 45MIN. ISMIN. SOMIN. I)MIN. 4MIN. I MIN. *200 1100 *60 '40 '30 *is *10 T *4 M. 3W 1W 3* V&' r 100 90 io so 2D 7D 30 SO 40 so 4- 40 30 F SG 20 60 0 '001 k 0.002 .005 009 019 .037 074 .149 297 0.42590 1.19 2.02.38 4.76 952 19.1 36.1 76.2 127 200 152 DIAMETER OF PARTICLE IN MILLIMETERS I CLAY (PLASTIC) TO SILT (NONELASTIC) SANDS i GRAVEL I FINE MEDIUM COARSE I FINE COARSE I COBBLES Sample of SAND, CLAYEY (SC) GRAVEL 3 % SAND 59% From 7119 AT 0-5 FEET SILT & CLAY -3-8-3r. LIQUID LIMIT 41 % PLASTICITY INDEX 28 0/b I HYDROMETER ANALYSIS I SIEVE ANALYSIS 25 MR. 7 HR. TOM READINGS U-S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN, 19 MIN. 4 MIN. 1 MIN. '200 1w *50 '40 -JO 116 110-8 *4 31W 314' 1-W V, 10D 5161, W, Iz- 20 70 40 so 40 AL2-77-1�- 50 - OC WE 30 70 .... ..... . ... 20 w 10 0 90 100 001 0002 005 009 019 017 074 149 DIAMETER 207 590 tig 20 238 475 952 191 361 762 0 OF PARTICLE IN MILLIMETERS 127 200 152 FLAY (PLASTIC) TO SILT (NON -PLASTIC) c SANDS � �COARSE GRAVELi I FINE I MEDIUM I j FINE I COARSE I COEaLES Sample Of SAND. CLAYEY (SC) GRAVEL 1 % SAND 75 % From 7H 2 AT 0-5 FEET SILT CLAY 24 % LIQUID LIMIT 48 r1b PLASTICITY INDEX Gradation. Test Results FIG. 3 CTL I T PROJECT NO. FC03508-135 I HYDROMETER ANALYSIS I SIEVE ANALYSIS 25HR. 714R. TIME READINGS US. STANDARD SERIES CLEAR SOUARi OPENINGS 45 MIN, 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 1100 '50 '40 '30 *16 110 08 *4 39r SIC 1W' 3" $'a' W 100 0 9U 10 20 -1- A . . . . . . . . . . . . . . . . . . 30 60 .40 t cuZi so 50 40 20 so lu 90 0 .001 a002 ODS .009 -019 .037 .074 149 �297 590 1.19 2.0 2,30 4.76 IL52 191 361 78.2 127 a4i 16�00 DIAMETER OF PARTICLE IN MILLIMETERS L CLAY (PLASTIC) TO SILT (NOWPLASTIC) SANDS GRAVEL FINE MEDIUM COARSE FINE COARSE COBBLES Sample W SAND, CLAYEY (SC) GRAVEL 7 % SAND 60% From TH 9 AT 0-5 FEET SILT & CLAY 33 % LIQUID LIMIT 39 % PLASTICITY INDEX 23 % I HYDROMETER ANALYSIS SIEVE ANALYSIS 25HR. 7HR. TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45MIN ISMIN. 60MIN. 19MIN. 4MIN. IMIN, 100 '200 1100 *50 '40 73D 116 110 *8 *4 3/6' 3W 111r T. V.&I a. 4. 0 4 oeosli= 9D 10 so L 20 7 05 30 z A. so z 40 so ___r t G:= AL so 60 F-1 M 30 —70 20 80 _T 9D 7--7-7- 0 001 0002 005 009 019 037 074 149 297 590 1 19 20 2r38 4 76 952 191 3s 1 762 127 200 100 042 152 DIAMETER OF PARTICLE IN MILLIMETERS CLAY C) TO SILT (NON -PLASTIC) j SANDS GRAVEL FINE MEDIUM COARSE FINE COARSE I COBBLES I Sample of SAND, CLAYEY (SC) From TH 4 AT 0-5 FEET GRAVEL i % SILT & CLAY 33% PLASTICITY INDEX Gradation SAND 66% LIQUID LIMIT 42% 29% Test Results FIG. 4 CTL I T PROJECT NO. FC03608-135 I HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR. ?HR. TIME READINGS U.S. STANDARD SERIES CLEM SOUARE OPENINGS 46MIN. 16MIN. 60MIN. 19MIN. 4MIN. 1MIN. '200 1100 '50 '40 '30 -16 -10-8 *4 3M. 100 3w 1w T' 5's' r 4 0 90 10 so ic-nz 70 so 40 50 Olt so w 411 77777= 7 60 ----- so 10 F.- 90 0 XCTI 0-002 005 ON 019 .037 .074 .149 297 .590 1.19 2.0 2.30 4.76 9.62 19.1 36.1 762 12,72DO 0.42 62 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT (NON -PLASTIC) SANis 1 II IEDIUM FINE COARSE -GRAVEL FINE COARSE COBBLESI - aUITIPIt;vI bANU,CLAYEY (8q) GRAVEL 0 % SAND 52% From -fH 9 AT 0-5 FEET SILT & CLAY 48 % LIOU16 LIMIT-46 % PLASTICITY INDEX 297a HYDROMETER ANALYSIS SIEVE ANALYSIS 25HR. 7HR. TIME READINGS U.S. STANDARD SERIES CLEAR SOIIA EOPENINGS 45MIN. 15MIN. 60MIN. 12MIN. 4MIN. IMIN. 200 *100 M *40 -X •is *10-8 '4 3/11' 314" i"T Y. 5.1e, S. IOD 0 90 4F=— . .... ... F 10 so 7� zr. 30 160 j.- 77-7:77=77=7 z IK so so 40 -7-7 60 30 ------------- 70 20 90 001 100 0002 005 009 019 037 074 149 297 590 1 19 2 0 2 38 4 76 952 191 361 762 127 200 042 152 DIAMETER OF PARTICLE IN MILLIMETERS CLAY I TO SILT (NON -PLASTIC) SANDS GRAVEL FINE MEDIUM COARSE FINE COARSE COBBLES Sample of CLAY, SANDY (CL) GRAVEL 0 % SAND 19% 6 From TH 6 AT 0-5 FEET SILT & CLAY T1 T LIOUID LIMIT 51 % PLASTICITY INDEX 36-9 Gradation Test Results FIG. 5 CTL I T PROJECT NO, FC03508-135 T TABLE OF CONTENTS SCOPE...........................................................................................................................1 SUMMARYOF CONCLUSIONS....................................................................................1 SITECONDITIONS........................................................................................................2 PROPOSEDCONSTRUCTION......................................................................................2 INVESTIGATION............................................................................................................ 2 SUBSURFACE............................................................................................................... 3 LABORATORY INVESTIGATION..................................................................................3 SUBGRADE PREPARATION.........................................................................................4 SOLUBLESULFATES...................................................................................................6 PAVEMENT DESIGN.....................................................................................................6 PAVEMENTMATERIALS..............................................................................................8 CONSTRUCTION DETAILS.........................................................................................11 MAINTENANCE...........................................................................................................11 LIMITATIONS...............................................................................................................12 FIGURE 1 - LOCATIONS OF EXPLORATORY BORINGS FIGURE 2 - SUMMARY LOGS OF EXPLORATORY BORINGS FIGURE 3 THROUGH FIGURE 7 - GRADATION TEST RESULTS FIGURE 8 AND FIGURE 9 - SWELL TEST RESULTS FIGURE 10 - HVEEM STABILOMETER TEST RESULTS TABLE 1 - SUMMARY OF LABORATORY TEST RESULTS APPENDIX A- FLEXIBLE PAVEMENT AND RIGID PAVEMENT DESIGN CALCULATIONS APPENDIX B - FLY ASH STABILIZATION CONSTRUCTION RECOMMENDATIONS APPENDIX C - MATERIAL PROPERTIES AND CONSTRUCTION CHECKLIST APPENDIX D - GUIDELINE MAINTENANCE RECOMMENDATIONS CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508.135 3.-1FC03508.000113512. Report 11FC03508.135.rpt.doc I HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR. 7 HR. TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MR IS MR 60 MIN, 19 MIN, 4 MIN. I MIN. -600 *100 *50 '40 '30 *16 *10 v *4 w 3w 111v- 3" V'S" W too -_4 90 10 Go — - - - - - - - - - - + 4----- 20 070 4 30 -- - --------- 60 I— 440 w so & ti ul 0 30 10 .DDI 0.002 '005 009 .019 .037 .074 .149 .297 590 1.19 ZO 2.36 4.76 952 191 36.1 76.2 127 2D0 OA2 152 DIAMETER OF PARTICLE IN MILLIMETERS inn CLAY (PLASTIC) TO SILT (NON -PLASTIC) SANDS GRAVEL FINE MEDIUM CDARSE FINE COARSE COBBLES -jample or SAND, CLAYEY (SC) GRAVEL 0 % SAND 66 % From TH 9 AT 0-5 FEET SILT & CLAY 34 % LIQUID LIMIT-44 % PLASTICITY INDEX 30% I HYDROMETER ANALYSIS SIEVE ANALYSIS 25 NFL 7 HA. TIME READINGS U.S, STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN, 19 MIN. 4 MIN. I MIM. '200 *100 *50 '40 30 116 "10 98 *4 316" 31'r, 1w, 3!' 5'6' a" 100 go --F . to z:-.- 4 so 20 7 H 30 40 w so ------ oif- P�-J so Lt 40 w 30 77: 70 L-- 20 80 10 90 001 0002 005 009 GIs 037 074 -:L too 149 297 590 119 20 238 476 952 191 351 762 12-7-200 042 152 DIAMETER OF PARTICLE IN MILLIMETERS CLAY (PLASTIC) TO SILT JNON-PLASTIC) SANDS GRAVEL FINE EDIUM COARSE FINE COARSE I C38-9NEiSll Sample of SAND, CLAYEY (SC) GRAVEL 0 % SAND 64% From TH 8 AT 0-5 FEET SILT& CL-A-Y----36-r/,- LIQUID LIMIT 47% PLASTICITY INDEX 32 Gradation Test Results FIG. 6 CTL I T PROJECT NO. FC03508-135 I HYDROMETER ANALYSIS SIEVE ANALYSIS 25HR, 7HR. TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN, I MIN. 200 1100 650 140 *30 .10 .10.8 *4 318" 3w VA* a, 6w, r 100 0 _4 110 Z_ 120 70 ------- T— so 40 ru so so 40 30 I_ . .... 60 z i 70 20 10 0 001 0,002 .019 .037 .074 .149 297 590 1.19 2.0 2.38 4.76 9.52 19A 36.1 762 127 200 0.42 152 DIAMETER OF PARTICLE IN MILLIMETERS ECLAY (PLASTIC) TO SILT (NON -PLASTIC) i SANDS GRAVEL FINE I MEDIUM ICOARSE I_ FINE I COARSE I COBBLES I sample or SAND, CLAYEY (SC) GRAVEL 0 % SAND 56% From 7119 AT 0-5 FEET SILT & CLAY 44 % LIQUID LIMIT 43 376 PLASTICITY INDEX I HYDROMETER ANALYSIS I SIEVE ANALYSIS 25 HR 7 HR. TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN, 15 MIN. 60 MIN. 19 MIN. 4 MIN, I MIN. *200 Ica so 140 130 is nola 14 W. 31'r 1wP Y, sple, v 10010 0 90 I 80 . . . . . . . . . . . . 20 70 z t-7 ... ... OW 50 ------- 50 40 7L EX UNG -5- 30 7- 7;7--7- 70 20 10L. 4 90 a Ica 001 0 002 005 009 019 03; 074 149 297 SW 1 19 2 0 2 39 4 76 952 191 361 762 127 200 042 152 DIAMETER OF PARTICLE IN MILLIMETERS I CLAY (PLASTIC) TO SILT (NON -PLASTIC) SANDS L GRAVEL FINE FINE � MEDIUM lCOARSE l FINE I COARSE COBBLES Sample of SAND, CLAYEY (SC)_ GRAVEL 0 % SAND 69% From -fH 10 AT 0-5 FEET SILT& CGVY-31 0/b LIQUID LIMIT 43% PLASTICITY INDEX 29 % Gradation Test Results FIG. 7 CTL I T PROJECT NO. FC03508-135 Kl 2 a z ° O 0 z Q IL -, z -2 0 y N W 0: -3 a 2 0 0 DUE TO 0., 1.0 ,° APPLIED PRESSURE - KSF Sample of SAND, CLAYEY (SC) NATURAL DRY UNIT WEIGHT= From TH2- AT 2 FEET NATURAL MOISTURE CONTENTa 7 e4 TO z 0 ° h z a a z 0 -2 N w W Ix -3 a g 0 U -q 100 103 PCF 22.6 % APPLIED PRESSURE - KSF ° 10 00 Sample of CLAY, SANDY (CL) NATURAL DRY UNIT WEIGHT= 102 PCF From TH6- AT 2 FEET NATURAL MOISTURE CONTENT= 22.9 % Swell Consolidation Test Results FIG.8 CTL I T PROJECT NO. FC03508-135 OLD LEGACY CUL-DE-SAC 1 I. z 0 O N z Q IL -1 x w 0 z .2 O N rn w a -3 a a O v DUE TO 0.1 1.0 10 APPLIED PRESSURE - KSF Sample of SAND, CLAYEY (Sc) NATURAL DRY UNIT WEIGHT= From TH10- AT 2 FEET NATURAL MOISTURE CONTENT= 3 2 M z O 0 N z a 91 -1 w e z o -2 1n w a -3 [L z O V -a 0.1 APPLIED PRESSURE - KSF Sample of From 10 10 100 108 PCF 18.9 % 100 NATURAL DRY UNIT WEIGHT= PCF NATURAL MOISTURE CONTENT= % Swell Consolidation Test Res u Its FIG. 9 U CTL I T PROJECT NO. FC03508-135 OLD LEGACY CUL-D6SAC M�dY Mv • .. .! .._____ -- 1 -. n. ------< --- -------=-------- ---------------- -------'-------- ............. -- > Group Number 800 AASHTO Classification A-7-6 Liquid Limit 51 - - Plasticity Index 36 ---------------- -------- -------------- ------ -�- --------------- - - - -------------- -- --- ----- 1 - Design R V I e g a ua 15 700 - - ----------- --- ------- ----------- ,--' -------- -------- - -- -- ----- -' - - - - 600 -- �- - --- - --------- ------ ------- - �- ---- ------ .............. . --------;-- --------.' ----- 500 - -- ------- 400 ------ ---------- --- - -- ---- - - - - -- -- -:---------- ------- -- ------------ ----- --�---------�---- ................................ - - l . ' -- ---- ' -- - ....!...--.... 300 __---- - -- -- --------------� ------------------------ . --- --------------- ---- - ------L 200 ---------------- ..................... .......... f --------- ------- --------- ----- - ................ -- - 100 "- - ...-' ---- - - 1- ----------------- -- --------- - - --• --------------... - 0 ---------- ---------------- ------ ------ -------- ------ I --- ----- ----- - I -- - - ------- ----- --- ----- ,-............... 10 20 30 40 "R" VALUE CTL I T PROJECT NO. FC03508-135 50 60 70 80 90 Hveem Stabilometer Test Results Fig. 10 TABLE I SUMMARY OF LABORATORY TEST RESULTS 2T NATURAL SWELL TEST DATA ATTERBERG LIMITS AASHTO CLASSIFICATION GROUP INDEX SOLUBLE PASSING Borin DEPTH NATURAL DRY SWELL APPLIED LIQUID PLASTICITY SULFATES NO.200 SOILTYPE MOISTUREDENSITY PRESSURE LIMIT INDEX SIEVE FEET (°k) PCF % PS % °k % % TH1 0-5 18.6 41 28 A•7-6 5 38 SAND, CLAYEY SC TH2 2 22.6 103 1.3 150 SAND CLAYEY SG TH2 0-5 21.4 48 32 A-2-7 0 0.01 24 SAND, CLAYEY SC TH3 0-5 18.5 39 23 A-2-6 2 33 SAND CLAYEY SC TH4 0-5 16.8 42 29 A-2-7 3 33 SAND, CLAYEY SC TH5 0-5 19.2 46 29 A-7-6 9 0.12 48 SAND, CLAYEY SC TH6 2 22.9 102.2 2.1 150 CLAY, SANDY CL 7H6 0-5 16.8 51 36 A-7-6 29 81 CLAY, SANDY CL TH7 0-5 20.8 44 30 A-2-7 4 34 SAND, CLAYEY SC TH8 0-5 20.5 47 32 A-7-6 5 36 SAND, CLAYEY SC TH9 0-5 21.8 43 28 A 77-6 7 44 SAND, CLAYEY SC TH10 2 16.9 108 1.3 150 SAND, CLAYEY SC TH10 0-5 17.6 1 1 1 43 29 A-2-7 2 31 ISAND, CLAYEY SC CTL I T PROJECT NO. FC3508-135 Page 1 of 1 Ll APPENDIX A FLEXIBLE PAVEMENT AND RIGID PAVEMENT DESIGN CALCULATIONS CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508-136 S:1FC03508.00MUM. Report 11FC03W8-135.rp(.doc FLEXI AASHBLE PAVEMENT TO DESIGN Project: ZEIGLER ROAD WIDENING Job No. FC03508-135 Location: Shallow Pond Drive to Trilby Road What is the Design ESAL ?IE�1(i What is the Serviceability Loss ? What is the Reliability ? J What is the Standard Deviation ?: What is the R-value ? 7 Computed Resilient Modulus = AN. psi If R is not available, Input Resilient Modulus I psi DESIGN RESILIENT MODULUS = 400 psi DESIGN STRUCTURAL NUMBER (SN) Full Depth HBP Thickness on Subgrade is inches What is the HBP Layer Coefficient ? What is the ABC Layer Coefficient ? What is the FASS Layer Coefficient? r!Sf< inches HBP over $i inches Aggregate Base Course NOTES: HBP = Hot Bituminous Pavement, ABC = Aggregate Base Course This table presents design parameters and pavement thickness calculations, and should not be used for construction purposes. Final pavement thicknesses are presented in the report. CTL I T PROJECT NO. FC03508-135 Page A-1 w.� AASHTO FLEXIBLE PAVEMENT DESIGN IF Project: TRILBY Job No. FC03508-135 Location: Zeigler Road to Southwest Corner of Kinnard Junior High School What is the Design ESAL ? What is the Serviceability Loss ? What is the Reliability ? What is the Standard Deviation ? What is the R-value ? Computed Resilient Modulus = If R is not available, Input Resilient Modulus = DESIGN RESILIENT MODULUS = DESIGN STRUCTURAL NUMBER (SN) _ Full Depth HBP Thickness on Subgrade Is?;,,,;,, finches What is the HBP Layer Coefficient ? What is the ABC Layer Coefficient ? What is the FASS Layer Coefficient? 7� Inches HBP over S inches Aggregate Base Course NOTES: HBP = Hot Bituminous Pavement, ABC = Aggregate Base Course This table presents design parameters and pavement thickness calculations, and should not be used for construction purposes. Final pavement thicknesses are presented in the report. CTL I T PROJECT NO. FC03508-135 Page A-2 L AASHTO FLEXIBLE PAVEMENT DESIGN Project: OLD LEGACY DRIVE Job No. FC03508-135 Location: Cul-de-Sac What is the Design ESAL ? What is the Serviceability Loss ? What is the Reliability ? What is the Standard Deviation ? What is the R-value ? Computed Resilient Modulus = If R is not available, Input Resilient Modulus = DESIGN RESILIENT MODULUS DESIGN STRUCTURAL NUMBER (SN) _ Full Depth HBP Thickness on Subgrade is What is the HBP Layer Coefficient ? What is the ABC Layer Coefficient ? What is the FASS Layer Coefficient? psi psi psi �i.8. inches inches HBP over inches Aggregate Base Course NOTES: HBP = Hot Bituminous Pavement, ABC = Aggregate Base Course This table presents design parameters and pavement thickness calculations, and should not be used for construction purposes. Final pavement thicknesses are presented in the report. CTL I T PROJECT NO. FC03508-135 Page A-3 SCOPE This report presents the results of our subgrade investigation and pavement design for the Zeigler Road widening from Shallow Pond Drive to Trilby Road, for Trilby Road from Zeigler Road to the southwest corner of the Kinard Junior High School site and for the Old Legacy Drive cul-de-sac. This Investigation was to Identify the type of subgrade soils under the proposed streets to be widened and paved and to send design pavement alternatives for paving the streets. We believe our report is in general conformance with Chapter 5 and Chapter 10 of the Larimer County Urban Areas Street Standards repealed and reenacted October 1, 2002, as adopted by the City of Fort Collins. Our report Includes a description of the subgrade soils penetrated by our exploratory borings, laboratory test results, recommended alternative pavement sections and construction and materials guidelines. Our recommendations are based upon laboratory test results, discussions with the City of Fort Collins project design team, City of Fort Collins design criteria, the American Association of State Highway Transportation Officials (AASHTO) 1993 "Guide for Design of Pavement Structures", and our experience. SUMMARY OF CONCLUSIONS 1. Our borings penetrated 5 feet and 10 feet of loose to medium dense, clayey sands and occasional layers of stiff sandy clays to the maximum depth drilled of 10 feet. Bedrock was not penetrated in the ten borings. 2. Ground water was encountered between 5.5 feet and 7.5 feet in 7 of the ten borings. 3. The subgrade soils have medium to high swell potential and fair to poor subgrade support characteristics. Mitigation measures are discussed in this report. 4. Subgrade soils should be scarified a minimum of 8 inches deep, moisture conditioned and compacted to at least 95 percent of Standard Proctor maximum dry density (AASHTO T 99). Sand soils should be moisture conditioned to 2 percent below to 2 percent CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, 1 ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508-135 WFC03508.00011 M. Report 1%FC03508.135.ept.do0 SHTO RIGID PAVEMENT DESIGN Project: ZEIGLER ROAD WIDENING Job No. FC03508-135 Location: Shallow Pond Drive to Trilby Road What is the Design ESAL ? What is the Reliability ? What is the Serviceability Loss ? What is the Concrete Elastic Modulus ? What is the Concrete Modulus of Rupture ? What is the Drainage Factor ? What is the Standard Deviation ? What is the Load Transfer Coefficient ? What is the R-value ? Computed Resilient Modulus = If R is not available, Input Resilient Modulus = DESIGN RESILIENT MODULUS = psi DSi psi psi DSi Design Slab Thickness is AS inches CTL I T PROJECT NO. FC03508-135 Page A-4 No Text AASHTO RIGID FAVEMENT DESIGN Project: OLD LEGACY DRIVE Job No. FC03508-135 Location: Cul-de-Sac What is the Design ESAL ? What is the Reliability ? What is the Serviceability Loss ? What is the Concrete Elastic Modulus ? What is the Concrete Modulus of Rupture ? What is the Drainage Factor ? What is the Standard Deviation ? What is the Load Transfer Coefficient ? What is the R-value ? Computed Resilient Modulus = If R is not available, Input Resilient Modulus = DESIGN RESILIENT MODULUS = Design Slab Thickness is psi psi psi psi psi inches CTL I T PROJECT NO. FC03508-135 Page A-6 IF APPENDIX B FLY ASH STABILIZATION CONSTRUCTION RECOMMENDATIONS CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508-135 S:%FC03S08.000YI3R2. Report 11FC03W8-135.rpl.00e 0 FLY ASH STABILIZATION CONSTRUCTION RECOMMENDATIONS 1. The areas to be treated should be cut within 6 inches of the bottom of the zone to be treated. The resulting surface should be prepared with a blade to provide a relatively smooth working area. 2. The bottom 6 inches of the treatment zone should be scarified and pulverized. Pulverization should be accomplished using a rototiller or similar device. The combination of scarifying and rototilling should result in a layer of soil approximately 8 inches in thickness pulverized to minus 1 inch in the area of stabilization. 3. When pulverization is complete, fly ash shall be applied at a rate of 12 percent of the dry compacted weight. The fly ash content can be made more precise by performing a mix design using on -site soils and the fly ash anticipated for the stabilization. 4. The fly ash should be spread uniformly across the area to be treated and mixed with a rototiller or similar device. 5. When sufficient soil and fly ash has been mixed, water should be added to bring the mixture to 2 percent to 5 percent above optimum moisture content for compaction. Optimum moisture content will be determined by compacting a sample of the mixture using ASTM D 698 compaction procedure. The area to be compacted should be rolled with a vibrating sheepsfoot or similar compactor until 95 percent of the maximum density determined using ASTM D 698 on the treated soil is achieved. 6. Subsequent lifts of the stabilized zone should be placed in an 8- inch thick loose lift(s), pulverized and compacted as described in Items 2 through 5 immediately above. 7. The final lift should be allowed to cure for 3 to 7 days or until a non -yielding surface is achieved. CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DESAC, Appendix B-1 ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03608.135 SAFC0350600011352. Report ITC03508.135rpLEoc Kim APPENDIX C MATERIAL PROPERTIES AND CONSTRUCTION CHECKLIST CITY OF FORT COLLINS OLD LEGACY DRIVE CLIL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508-135 "C03505.000113512. Report 1iFC03508.135.rplADC MrWY �Nr... r T MATERIAL PROPERTIES ASPHALT CONCRETE n Design assumes a strength coefficient of 0.44. n Asphalt concrete should be relatively impermeable to moisture and should be designed with 100% crushed aggregates that have a minimum of 80% of the aggregate retained on the No. 4 sieve with two mechanically fractured faces. n Gradations that approach the maximum density line (within 5% between the No. 4 and 40 sieve) should be avoided. n A gradation with a nominal maximum size of 3/4" developed on the fine side of the maximum density line should be used. n Total void content, Void in the Mineral Aggregate (VMA) and voids filled shall be considered in the selection of the optimum asphalt cement content. The optimum asphalt content shall be selected at a total air void content of 4%. The mixture shall have a minimum VMA of 14% and voids filled that range from 65 to 80%. n Polymer modification can change the rheology and viscosity to improve pavement performance and is recommended for the upper 3 inches of collector and arterial streets. n Residential streets should be fog sealed approximately 30 days after the placement of asphalt concrete at 0.1 to 0.15 gallons per square yard. n A job mix design and periodic checks on the job site shall be made to verify compliance with the specifications. AGGREGATE BASE COURSE n Design assumes a minimum Hveem stabilometer value of 70. n A Class 5 or 6 Colorado Department of Transportation (CDOT) specified aggregate base course is recommended. n Aggregate base must be moisture stable. The change in R-value from 300 psi to 100 psi exudation pressure must be 12 points or less. If the construction materials cannot meet these recommendations, then the pavement design should be evaluated based upon available materials. Materials and placement methods should conform to the requirements of the City of Fort Collins. All material planned for construction should be submitted and the applicable laboratory tests performed to verify compliance with the specifications. CITY OF FORT COLLINS Appendix C-1 OLD LEGACY DRIVE CUL-DE-SAC, pP ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03505-135 S:1FC03500.000N3512, Report 11FC03505.133.rpt.doc CONSTRUCTION CHECKLIST The construction procedure of the pavement system Is as important as the quality of the materials. Inadequate compaction of the subgrade is often the reason for early pavement failure, resulting in pavement instability, rutting, cracking, settlement and heave. We recommend the proposed pavement be constructed in the following manner. PREPARATION Subgrade Preparation > Subgrade shall be stripped of organic matter, scarified, moisture treated, and compacted. > Utility trenches and all subsequently placed fill shall also be compacted and tested prior to paving. > Final grading of the subgrade should be carefully controlled so the design cross -slope is maintained and low spots in the subgrade that could trap water are eliminated. Granular Soils (A-2-4 and A-4) > Soils shall be moisture treated to within 2% of optimum moisture content. > Soils shall be compacted to at least 95% of maximum standard Proctor dry density (ASTM D 698, AASHTO T 99). Cohesive Soils (A-6 to A-7-6) > Soils shall be moisture treated between optimum and 3% above optimum moisture content. > Soils shall be compacted to at least 95% of maximum standard Proctor dry density (ASTM D 698, AASHTO T 99). Proof Testing > After final subgrade elevation has been reached and the subgrade compacted, the area shall be proof -rolled with a pneumatic -tired vehicle loaded to at least 18 kips per axle. > Subgrade that is pumping or deforming shall be scarified, moisture conditioned, and tested. > If areas of very soft or wet subgrade are found, the material shall be sub -excavated and replaced with approved on -site or import material, moisture conditioned, compacted and tested. CITY OF FORT COLLINS Appendix C-2 OLD LEGACY DRIVE CUL-DE-SAC. ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508.135 S:IFC0350l.000%13W. Report 1WC03003.135.rpl.doc Project: TRILBY Job No. FC03508-135 Location: Zeigler Road to Southwest Corner of Kinnard Junior High School What is the Design ESAL ? What is the Reliability ? What is the Serviceability Loss ? What is the Concrete Elastic Modulus ? What is the Concrete Modulus of Rupture ? What is the Drainage Factor ? What is the Standard Deviation ? What is the Load Transfer Coefficient ? What is the R-value ? Computed Resilient Modulus = If R is not available, Input Resilient Modulus = DESIGN RESILIENT MODULUS = Design Slab Thickness is $,ti inches CTL I T PROJECT NO. FC03508-135 Page A-5 0 ASPHALT CONCRETE > Asphalt concrete shall be hot plant -mixed material compacted to at least 92 to 96% of maximum theoretical density. > Paving should only be performed when subgrade temperatures are above 400 F and air temperature is at least 400 F and rising. > The temperature at laydown time shall be determined according to the temperature -viscosity relationship of the asphalt cement. Experience indicates that the laydown temperature shall be at least 2750 F for AC-10 asphalt cement. > The maximum compacted lift for 3/4 inch nominal aggregate size bituminous pavement should be 3.0 inches and joints shall be staggered. No joints shall be placed within wheel paths. > Surface shall be sealed with a finish roller prior to the mix cooling to 1750 F. CITY OF FORT COLLINS Appendix C-4 OLD LEGACY DRIVE CULAS EAC, pp ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03506-135 &WC03508.000113M. Report 11FC03508•135aptdoe MuY above optimum moisture content. Clay soils should be moisture conditioned to between optimum moisture content and 3 percent above optimum moisture content. 5. Pavement sections using asphaltic concrete pavement on prepared subgrade, asphaltic concrete pavement on compacted aggregate base course and concrete pavement are discussed in this report. SITE CONDITIONS Kinard Junior High School is located just outside of the southeastern corner of the City of Fort Collins. The Old Legacy Drive cul-de-sac is located on the northern boundary of the school site. Zeigler Road borders the eastern side of the school site and will be widened. Trilby currently ends at the intersection with Zeigler Road at the southeast corner of the school site. The alignment of the proposed stretch of Trilby Road is a cornfield with standing corn along the south side of the school site. PROPOSED CONSTRUCTION The proposed project includes the widening of about 750 feet of Zeigler Road from Shallow Pond Drive to Trilby Road, constructing about 1000 feet of Trilby Road from the Zeigler Road/Trilby Road intersection to the southwest corner of the Kinard Junior High School site and paving the Old Legacy Drive cul- de-sac in Fort Collins, Colorado (see Figure 1). The stretch of Zeigler Road will be widened on its west side. A traffic control island is proposed at the Trilby Road intersection with Zeigler Road in Trilby Road. There is also a waterline planned along the south side of the Trilby Road right-of-way. INVESTIGATION Subsoils were investigated by drilling ten exploratory borings. Four borings were drilled to 10 feet in the proposed widening of Zeigler Road at approximate intervals of 200 feet, five borings were drilled to 10 feet for the Trilby Road construction at approximate intervals of 250 feet and one boring was drilled CITY OF FORT COLLINS 2 OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03500.135 SAFC03808.000MM. Reper111FC03508.135.rpl.doc APPENDIX D GUIDELINE MAINTENANCE RECOMMENDATIONS CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FCMUB-135 &IFC03506.000113M, Report 1lFC03608435.IpLAoc T- MAINTENANCE RECOMMENDATIONS FOR FLEXIBLE PAVEMENTS The primary cause for deterioration of low traffic volume pavements is oxidative aging resulting in brittle pavements. Tire loads from traffic are necessary to "work" or knead the asphalt concrete to keep it flexible and rejuvenated. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal or rejuvenating the asphalt binder to extend pavement life. 1. Annual Preventive Maintenance a. Visual pavement evaluations shall be performed each spring or fall. b. Reports documenting the progress of distress shall be kept current to provide information on effective times to apply preventive maintenance treatments. C. Crack sealing shall be performed annually as new cracks appear. 2. 3 to 5 Year Preventive Maintenance a. The owner should budget for a preventive treatment at approximate intervals of 3 to 5 years to reduce oxidative embrittlement problems. b. Typical preventive maintenance treatments include chip seals, fog seals, slurry seals and crack sealing. 3. 5 to 10 Year Corrective Maintenance a. Corrective maintenance may be necessary, as dictated by the pavement condition, to correct rutting, cracking and structurally failed areas. b. Corrective maintenance may include full depth patching, milling and overlays. C. In order for the pavement to provide a 20-year service fife, at least one major corrective overlay can be expected. CITY OF FORT COLLINS Appendix D-1 OLD LEGACY DRIVE CUL-DE-SAC,pP ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03503-135 SAFC03505A001135M Report 11FC03508-135.rpt doc I to 5 feet in the proposed Old Legacy Drive cul-de-sac. The boring locations are shown on Figure 1. The borings were drilled with a truck -mounted drill rig using 6-inch diameter continuous flight augers. Soils were sampled by driving a California sampler with a 140-pound hammer falling 30 inches and by collecting bulk samples from the auger cuttings. SUBSURFACE Our borings penetrated 5 feet to 10 feet of clayey sands. The sands were medium dense overlying looser sands. The sands were bedded with occasional thin layers of stiff, sandy clays. The clayey sands and sandy clays were moist to very moist. Bedrock was not encountered in the ten borings. We encountered ground water in 7 of the 10 borings from 5.5 feet to 7.5 feet. Summary logs of the borings, Including results of field penetration resistance tests, are shown on Figure 2. LABORATORY INVESTIGATION The laboratory investigation for the pavement subgrade soils was designed to provide Index properties, swell/consolidation characteristics, and subgrade support values for those soils that influence the pavement design. Index properties of the soils sampled were measured and the soils were classified according to AASHTO and the Unified Soil Classification System. The soils classified as follows: five samples were A-7-6, 4 samples were A-2-7 and one sample was A-2-6 according to the AASHTO classification. Nine of the samples were classified as clayey sands (SC) and one sample was classified as a sandy clay (CL) according to the Unified Soil Classification System. The samples had group indices ranging from 0 to 29. CITY OF FORT COLLINS OLD LEGACY DRIVE CUL-DE-SAC, 3 ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL [ T PROJECT NO. FC03508-135 SAFC03508.000UM. Report 1%FC03808.975.rpt.d" No The samples tested had liquid limits ranging from 22 percent to 41 percent and plasticity indices from 23 percent to 36 percent. The samples had 24 percent to 81 percent silt and clay -sized particles (passing the No. 200 sieve) with the majority of the samples having between 33 percent and 48 percent. A Hveem Stabilometer test (R-value) (ASTM D 2844, AASHTO T 190) was performed on the sample of clays (A-7-6) because it was judged to be the poorest sample and an R- value of 15 (see Figure 10) was obtained. We tested three samples in our swell/consolidation apparatus. The samples were lightly loaded to 150 psf, flooded with water and allowed to swell or consolidate. Test results indicated medium swell for the A-2-7 soils (1.3 percent) and high for the A-7-6 soil (2.1 percent). Swell test results are presented on Figure 8 and Figure 9. Based on the swell test data, Atterberg limits, visual observations of the soils and our experience, we judge the swell potential of subgrade soils to be high, using the Larimer County Urban Area Street Standards. Laboratory test results are presented on Figure 3 through Figure 10 and summarized in Table I. SUBGRADE PREPARATION The subgrade soils under the Zeigler Road widening, Trilby Road construction and Old Legacy Drive cul-de-sac are medium to high swell potential. Soils with this swell potential will require mitigation per the Urban Area Street Standards. Mitigation measures include over excavation and replacement with non -expansive or low -expansive material or chemical treatment such as mixing the on -site soils with fly ash (preferred by Street Oversizing Department). Lime and cement are also mixed with on -site soils to provide mitigation. Finally, sub drains have proved effective. Drains, if selected as part of the mitigation treatment, should be designed as required by the Larimer County Urban Area Street Standards. CITY OF FORT COLLINS 4 OLD LEGACY DRIVE CLIL-DESAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508.135 S:IFC035D8.000113513. Report %FC03505.135.rpLtloc &� I it Should the over -excavation and replacement measure be selected we believe the depth should be of the order of 2.5 feet below rough subgrade elevation for the street widening and street construction proposed for this project. Should the chemical treatment measure be selected we believe the depth should be 1 foot below rough subgrade elevation for the street widening and street construction for this project. Subgrade (the subgrade would be non -expansive or low -expansive material if over -excavation mitigation measure is selected) immediately below the pavement section (not applicable if chemical treatment mitigation is selected) should be scarified a minimum of 12 inches deep, moisture conditioned to between 2 percent below and 1 percent above optimum moisture content and compacted to at least 95 percent of standard maximum dry density (ASTM D 698). Scarification and re -compaction of the upper 12 inches of subgrade soils should occur as close to the time of pavement construction as possible. The final subgrade surface must be protected from freezing and from excessive drying or wetting until such time as the pavement section is constructed. If chemical treatment is chosen for mitigation or stabilization, it should be done as close to the time of pavement construction as possible to avoid damage to the finished surface. On -site soils substantially free of trash, debris, organics or other deleterious materials are suitable for re -use as fill. Imported fill should consist of soils with properties similar or better than the on -site soils. Samples of the proposed fill should be submitted to our office for approval prior to importing to the site. A representative of our firm should observe placement and test compaction of fill. Proper grading and drainage and maintaining moisture contents near optimum will be critical to avoid excessive deflections, rutting and pumping of the roadway during subgrade preparation. If moisture and density cannot be sufficiently controlled during subgrade preparation and stabilization is required, stabilization by removal and replacement or stabilization using geotextile fabrics CITY OF FORT COLLINS 5 OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508-135 SAFC03508A00V13512. Report MC0350e.135.apl.doc U and/or imported granular and rock materials may be used. For isolated or small areas requiring stabilization, removal and replacement or "crowding" angular, coarse aggregate Into the subgrade may be effective. SOLUBLE SULFATES Water-soluble sulfate (SO4) concentrations were measured for two samples of the near -surface subgrade soils to determine the risk of exposure to sulfate attack where portland cement concrete is used and to assess the risk of increased swelling due to reaction to chemical stabilization. Concentrations of 0.01 and 0.12 percent were measured. These results indicate Class 0 (formerly "negligible") and Class I (formally "moderate") exposure to sulfate attack on concrete (e.g. curb and gutter or pavements) according to the American Concrete Institute (ACI). These results also indicate low risk of increased swelling due to reaction from chemical stabilization. ACI recommends Type II cement be used in concrete with moderate exposure to sulfate attack. For this site, Type II cement should be used in concrete. The water-cementitious material ratio should be 0.50 or less. ACI also recommends concrete in Class I exposure environments have a minimum compressive strength of 4000 psi. PAVEMENT DESIGN We used the AASHTO design method in accordance with the City of Fort Collins requirements. The City of Fort Collins designated Zeigler Road as a two lane arterial that should be designed for an Equivalent Daily Load Application (ESLA) value of 125 (912,500 ESAL) Trilby Road as an industriallcommercial collector that should be designed for an EDLA value of 100 (730,000 ESAL) and the Old Legacy Drive cul-de-sac as residential single lane that should be designed for an EDLA value of 10 (73,000 ESAL). CITY OF FORT COLLINS I) OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I T PROJECT NO. FC03508-135 S:IFC03508.000%13512. Report 11FC03508.135.apt.000 Using the traffic loading specified we calculated the design pavement sections shown below. Provided are alternatives for asphalt on aggregate base course, asphalt on aggregate base course on fly ash stabilized subgrade and portland cement concrete on a fly ash stabilized subgrade. Pavement section calculation worksheets are included in Appendix A. The strength of the fly ash stabilized subgrade was ignored in our pavement section calculations for the sections shown in the following table. PAVEMENT SECTIONS "� x,y:, # f Asphalt (�C}�onfrf /sl4halt AC 4+ CPoitland`Cemst + ' ^ruw .Design Location=� I14 �gi reg`ete Bas"e t ,x }fi 5. " , Concrete (PCP) h r Y t t �Cww� ttttrse• ABC ". 4 t pABC+ " ayry s t A y eN „t umrh .: r>;< bJKiHgM Zeigler Road from 8" AC + 8" AC + 6" ABC Shallow Pond Drive 6r. ABC + 12" FASS 8.5" PCCP 4.09 to TrilbyRoad Trilby Road from Zeigler Road to 7" AC + 7" AC + 6" ABC Southwest corner 6" ABC + 12" FASS 8" PCCP 3.76 of Kinard Junior HI h School Slte Old Legacy Drive 4.5" AC + 4.5" AC + B" cul-de-sac 6" ABC ABC + 12" 5" PCCP 2.55 FASS We recommend a pavement section consisting of 8 inches of asphaltic concrete (AC) and 6 inches of compacted aggregate base course (ABC) over 12 inches of fly ash stabilized subgrade (FASS) (see Appendix B) for the Zeigler Road widening, a pavement section of 7 inches of asphaltic concrete (AC) and 6 inches of compacted aggregate base course over 12 inches of fly ash stabilized subgrade (FASS) for the Trilby Road construction and a pavement section consisting of 4.5 inches of asphaltic concrete (AC) and 6 inches of compacted aggregate base course (ABC) over 12 inches of fly ash stabilized subgrade (FASS) for the Old Legacy Drive cul-de-sac. We believe these are reasonable design alternatives and appear to be required for swelling soil mitigation by the City regulations in the light of the swelling soil subgrade indicated by our laboratory investigation. CITY OF FORT COLLINS 7 OLD LEGACY DRIVE CUL-DE-SAC, ZEIGLER ROAD WIDENING AND TRILBY ROAD CTL I TPROJECT NO. FC03508.136 WFC03505.000113512. Report 11FC03505.135.rpt.doc