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HomeMy WebLinkAboutReports - Soils - 01/13/2025 CTL|Thompson, Inc. Denver, Fort Collins, Colorado Springs, Glenwood Springs, Pueblo, Summit County – Colorado Cheyenne, Wyoming and Bozeman, Montana Pickleball Courts and Parking Lot 4401 Innovation Drive Fort Collins, Colorado Prepared for: Old Town Designs, Inc, 2101 E. Oak Street Fort Collins, Colorado 80524 Attention: Keira Harkin Project No. FC11440.000-135 January 13, 2025 SUBGRADE INVESTIGATION AND PAVEMENT RECOMMENDATIONS Table of Contents Scope 1 Summary Of Conclusions 1 Site Location and Project Description 2 Field and Laboratory Investigation 2 Subsurface Conditions 3 Existing Pavement Materials 3 Clay 3 Groundwater 4 Site Development 4 Fill Placement 4 Excavations 5 Pavement Condition Survey 5 Pavement Design 6 Traffic Projections 6 Subgrade and Groundwater Conditions 6 Pavement Thickness Calculations 7 Pavement Recommendations 7 Subgrade and Pavement Materials and Construction 7 Outdoor Pickleball Court Slabs 8 Over-Excavation 10 Water-Soluble Sulfates 10 Maintenance 12 Surface Drainage 12 Limitations 13 FIGURE 1 – LOCATIONS OF EXPLORATORY BORINGS APPENDIX A – SUMMARY LOGS OF EXPLORATORY BORINGS APPENDIX B – RESULTS OF LABORATORY TESTING APPENDIX C – PAVEMENT DESIGN CALCULATIONS APPENDIX D – SAMPLE SITE GRADING SPECIFICATIONS APPENDIX E – PAVEMENT CONSTRUCTION RECOMMENDATIONS APPENDIX F – MAINTENANCE PROGRAM OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 1 Scope This report presents the results of our subgrade investigation and pavement recommendations for the proposed parking lot reconstruction and post-tensioned (PT) slabs to be used as pickleball courts in Fort Collins, Colorado. The purpose of our subgrade investigation was to determine the subsurface conditions and to evaluate pavement support characteristics for our pavement recommendations. The report was conducted in general conformance with Chapters 5 and 10 of the Larimer County Urban Areas Street Standards (LCUASS) dated January 2, 2001 (repealed and reenacted August 1, 2021) as adopted by the City of Fort Collins (City). This report was prepared from data developed during field exploration, laboratory testing, engineering analysis, and experience with similar conditions. The report includes a description of the subsurface conditions found in exploratory borings, laboratory test results, and pavement construction and material recommendations for the reconstruction of a parking lot. If plans change significantly, we should be contacted to review our investigation and determine if our recommendations still apply. A brief summary of our conclusions is presented below, with more detailed criteria and recommendations contained in the report. Summary Of Conclusions 1. Soils encountered in our borings generally consisted of at least 10 feet of sandy clay. Bedrock was not encountered at the depths explored. 2. Groundwater was measured at depths ranging from 8 to 9 feet in three borings during drilling. Existing groundwater levels are not expected to affect pavement or PT slab construction or performance. 3. The subgrade soils classified as A-7-6 which are considered to exhibit poor subgrade support. 4. Mitigation for swelling soils below pavements will be required. Mitigation should consist of removing, moisture conditioning, and recompacting of the upper 12 inches of the subgrade. 5. Asphaltic concrete is appropriate for parking lot pavements. Minimum pavement recommendations are presented in this report. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 2 6. Mitigation for swelling soils below the outdoor pickleball courts will also be required. Mitigation should consist of removing, moisture conditioning, and recompacting the upper 4 feet of subgrade. Site Location and Project Description The project site at 4401 Innovation Drive is located north of Harmony Road and west of Timberline Road in Fort Collins, Colorado (Figure 1). The extents of the project include the reconstruction of the parking lot and construction of three PT slabs to be used as outdoor pickleball courts. A pond is 300 feet north of the site. The existing parking lot is paved with asphaltic concrete over aggregate base course with no curb and gutter. We observed various distresses throughout the parking lot including rutting, cracking, potholes, and patching. Further descriptions of the condition of the existing pavement are provided in the Existing Pavement Materials and Pavement Condition Survey sections of this report. The planned improvements to the parking lot include reconstruction of most of the pavements, improvements to islands, and other associated features. We understand the Client desires recommendations for full reconstruction of the parking lot using asphaltic concrete over aggregate base course. Field and Laboratory Investigation Our field investigation consisted of drilling four borings in the parking lot to a depth of approximately 10 feet, measuring existing asphalt and aggregate base course thicknesses, logging the subsurface conditions, recording penetration-resistance tests, and acquiring samples of the subgrade materials. The approximate locations of our borings are presented on Figure 1. Two additional borings were drilled next to the building for the PT slabs. The borings were drilled with 4-inch diameter solid-stem augers and a truck-mounted drill. Our field representative directed the field investigation as the borings were advanced. Bulk samples were obtained from the upper 4 feet of the borings and modified California samples were obtained from selected intervals within the borings. The number of blows from a 140-pound hammer falling 30 inches, required to drive the modified California sampler, were recorded. We backfilled the borings with flow-fill and cold patch immediately after drilling. Summary logs of the borings, including results of field penetration resistance tests, are presented in Appendix A. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 3 After the samples were returned to our laboratory, our geotechnical engineer for this project examined the samples and assigned laboratory testing. Laboratory testing was performed in general accordance with AASHTO and ASTM methods to determine index properties, classification, and subgrade support values for those soil types influencing the pavement design. To evaluate potential heave, swell-consolidation testing was performed on samples of the subgrade soils under a pressure of 150 pounds per square foot (psf) as required under LCUASS. Other laboratory tests and analysis included moisture content, dry density, Atterberg limits, gradation analysis, swell consolidation, and water-soluble sulfate tests. Results of our laboratory tests are presented in Appendix B and summarized in Table B-I. Subsurface Conditions Existing pavement materials consisted of asphaltic concrete (AC) and aggregate base course (ABC) overlying subgrade soils. Soils encountered in our borings generally consisted of sandy clay. Groundwater was encountered in three borings. Further descriptions of these materials are presented in the following sections. Summary logs of the borings are presented in Appendix A. Existing Pavement Materials Thicknesses of existing pavement materials were variable at our boring locations. Approximately 3 inches to 4 inches of AC over 3 inches to 4 inches of ABC was measured in the borings located in the parking lot. Based on our experience with the City, asphalt and/or aggregate base course thicknesses are greater in patched and/or repaired areas that may have not been encountered in our borings. Clay Soft to very stiff, sandy clays were encountered in all borings to the depths explored. Seven samples of clay tested in the laboratory contained 55 to 76 percent clay and silt-sized particles (passing the No. 200 sieve). Seven of the samples had liquid limits of 43 to 61 and plasticity indices of 27 to 44. Swell potential varied from 0.8 to 2.2 percent below pavements and 2.3 to 3.6 percent in the locations of the pickleball courts. The clay classified as A-7-6 in accordance with the AASHTO classification method with a group Indices of 11.9 to 33.2. The clay is considered to exhibit poor subgrade support. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 4 Groundwater Groundwater was encountered in three borings at depths ranging from approximately 8 to 9 feet. Groundwater levels will vary seasonally. Groundwater levels are not expected to affect parking lot paving or PT slab construction. Site Development Fill Placement The existing onsite soils are generally suitable for re-use as new fill from a geotechnical standpoint, provided debris or deleterious organic materials are removed. In general, import fill should meet or exceed the engineering qualities of the onsite soils. In addition, particles larger than 3 inches should be broken down or removed. If import material is used, it should be tested and evaluated for approval by CTL|Thompson. Prior to fill placement, debris, organics/vegetation, and deleterious materials should be substantially removed from areas to receive fill. The surface should be scarified to a depth of at least 8 inches, moisture conditioned and compacted to the criteria below. Subsequent fill should be placed in thin (8 inches or less) loose lifts, moisture conditioned, and compacted. Fill should be compacted to a dry density of at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). Fill depths greater than 15 feet should be evaluated by CTL|T to recommend appropriate compaction specifications. Sand soils used as fill should be moistened to within 2 percent of optimum moisture content. Clay soils should be moistened between optimum and 3 percent above optimum moisture content. The fill should be moisture conditioned, placed in thin, loose lifts (8 inches or less), and compacted as described above. We should observe placement and compaction of fill during construction. Fill placement and compaction should not be conducted when fill material is frozen. CTL|Thompson should observe placement and compaction of fill during construction. Site grading in areas of landscaping where no future improvements are planned can be placed at a dry density of at least 90 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). Example site grading specifications are presented in Appendix C. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 5 Excavations We believe the soil penetrated in our exploratory borings can generally be excavated with conventional, heavy-duty excavation equipment. However, some of the soils are soft and will be displaced if wheeled equipment is used in the excavations. We recommend wheeled traffic not be allowed in the excavations. Excavations should be sloped or shored to meet local, State, and Federal safety regulations. Excavation slopes specified by OSHA are dependent upon types of soil and groundwater conditions encountered. The contractor’s “competent person” is responsible to identify the soils and/or rock encountered in excavations and refer to OSHA standards to determine appropriate slopes and safety measures. Based on our investigation and OSHA standards, we believe the sandy clay soils may classify as Type C soils. Type C soils require a maximum slope inclination of 1.5:1 in dry conditions. Stockpiles of soils, rock, equipment, or other items should not be placed within a horizontal distance equal to one-half the excavation depth, from the edge of excavation. Excavations deeper than 20 feet should be braced, or a professional engineer should design the slopes. Wind and water erosion is more likely with disturbed conditions expected during construction and may need to be addressed due to municipal regulation. The erosion potential will decrease after construction if proper grading practices, surface drainage design and re-vegetation efforts are implemented. Pavement Condition Survey The existing parking lot is paved with asphaltic concrete over aggregate base course with no curb and gutter. We observed various distresses throughout the parking lot including rutting, cracking, potholes, and patching. Some of the cracks are large enough for vegetation to grow. There was some evidence of past maintenance, including crack seal and utility patches. The pavement maintenance appears to be many years old. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 6 The concrete islands in the parking lot appeared to be in relatively good condition. Some of the concrete was chipped or cracked, but these were minimal. The Client may choose whether or not to demolish the concrete islands. Pavement Design Total reconstruction is planned for the parking lot. We understand improvements to the parking lot are regulated by the City of Fort Collins and LCUASS, which requires the use of the AASHTO and CDOT pavement design methods for their roadways. These design methods require input parameters for traffic projections for a specified design life, roadway classification, characteristics of the subgrade materials, type and strength characteristics of pavement materials, groundwater conditions, drainage conditions, number of construction stages, minimum pavement sections, and statistical data. Traffic Projections The traffic projections are based on vehicle loading, traffic volume, design period, and growth factor. Traffic projections are expressed as an 18-kip Equivalent Daily Load Application (EDLA) for a single day and as an 18-kip Equivalent Single Axle Load (ESAL) for the design period, which is typically 20 years. For the parking lot, we used the minimum ESAL provided in Table 10-1 of LCUASS for a residential two-lane road. An ESAL of 36,500 was used in our calculations. Subgrade and Groundwater Conditions The subgrade soils consist of sandy clay that classifies as A-7-6 in accordance with AASHTO classification methods. An R-value of 5 was used in our calculations, which is the minimum R-value provided by CDOT, which we converted to a resilient modulus of 5,356 psi based on CDOT Eq. 4-1 of the 2021 CDOT-PDM. Swell tests indicate the subgrade soils have a low to medium expansion potential based on Table 10-3 of LCUASS. LCUASS requires swell mitigation where swell is 2 percent or greater. Based on the results of laboratory testing and LCUASS, we believe that mitigation for swell will be required. Swell mitigation should consist of removing, moisture conditioning, and recompacting the upper 12 inches of subgrade. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 7 Groundwater was encountered in the borings at depths ranging from 8 to 9 feet. Groundwater located at least 5 feet below the subgrade surface is not expected to interfere with the performance of the pavement. Pavement Thickness Calculations We used the AASHTO design method to develop our pavement thickness calculations for flexible pavements with input values provided by LCUASS, CDOT-PDM, and our laboratory tests and observations. For our design, we assumed the pavement will be constructed during a single stage. Input values including initial and terminal serviceability indices, reliability factor, layer strength coefficients, and minimum sections were provided by LCUASS. Other input values not specified by LCUASS or CDOT-PDM were estimated based on our experience with similar projects. Computer generated printout of the AASHTO calculations are presented in Appendix C. Pavement Recommendations For our design, we assume the pavement will be constructed during a single stage. If multiple-stage construction is desired, we should be consulted to revise our recommendations. We have provided pavement design alternatives for new construction using hot mix asphalt (HMA) on aggregate base course (ABC) in the table below. Pavement Thickness Recommendations Paving Area Hot Mix Asphalt (HMA) + Aggregate Base Course (ABC)+ Moisture Treated Subgrade (MTS) Parking Lot 4” HMA + 6” ABC+ 12” MTS Subgrade and Pavement Materials and Construction The construction materials are assumed to possess sufficient quality as reflected by the strength factors used in our design calculations. Materials and construction requirements of LCUASS, CDOT-PDM, and 2023 CDOT Standard Specifications for Road and Bridge Construction should be followed. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 8 Based on the results of laboratory testing and LCUASS, we believe that mitigation for swell will be required. We understand for swell mitigation, LCUASS allows for moisture treatment of subgrade soils to reduce the swell potential to an acceptable level (less than 2 percent). We believe that removing, moisture conditioning, and recompacting of the upper 12 inches of subgrade is appropriate for this site. These criteria were developed from analysis of the field and laboratory data, our experience and LCUASS requirements. If the materials cannot meet these requirements, our pavement recommendations should be re-evaluated based upon available materials. The use of recycled materials, such as recycled asphalt pavement (RAP) and recycled concrete may be used in place of aggregate base course provided they meet minimum R-values and gradations established by LCUASS and CDOT. Materials planned for construction should be submitted and the applicable laboratory tests performed to verify compliance with the specifications. Outdoor Pickleball Court Slabs Our investigation indicates low to moderate swelling soils are present near anticipated slab-on-grade levels. We believe post-tensioned slab (PTS) can be used for the outdoor pickleball courts, provided they are designed and constructed to the criteria below, and the soil beneath the court is moisture treated to a depth of 4 feet beneath the foundation. PTS design is based on a method developed by the Post-Tensioning Institute (PTI, 3rd Edition, 2008). Various climate and relevant soil factors are required to evaluate the PTI design criteria. These include the Thornthwaite Moisture Index (Im), suction compression index (γh), unsaturated diffusion coefficient (α), depth of probable moisture variation, initial and final soil suction profiles, percent clay fraction and predominant clay mineral. In the Fort Collins area, the I m is around negative 25. Based on laboratory test results and the 2004 PTI design method, we estimate γh of 0.041 and an α of 0.004 are appropriate for the outdoor pickleball courts. The PTI design procedure is based upon soil movement that is primarily controlled by climate. The 2008 design estimates movements for a depth of wetting of 9 feet below the ground surface. Based on our experience in the Fort Collins area as well as field data, the depth of wetting will likely be about 15 or more feet below the ground surface. It is possible wetting will not penetrate this deep; however, we believe it is a reasonable design assumption for this site (groundwater is at about 8 to 9 feet). Ground movements can be estimated based on swell. The OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 9 PTI design procedure does not predict soil movement caused by site conditions such as irrigation or poor surface drainage that may lead to deeper wetting. If deeper wetting of the subgrade soils occurs, the slab movement may exceed the design movements in the PTI procedure. The PTI slab design includes evaluation of two mechanisms of soil movement (edge lift and center lift) based on assumptions that the wetting and drying of the foundation soils are primarily affected by the climate. Our experience indicates that the slab subgrade soils will normally undergo an increase of moisture due to covering of the ground surface by the slabs and irrigating around the buildings. Sub-excavation and placement of moisture treated fill below the slabs should help reduce the potential increase because the fill was placed at comparatively high moisture. Depending upon the surface drainage or the amount of available water, the differential, edge and center lift which control design could approach total heave. The edge moisture variation distance can also be more than the design values provided in the PTI manual. Considering the limitations of the current PTI design methodology, we believe a conservative approach with reasonable engineering judgment is merited in PTS design. We calculated the estimated heave value for the slab subgrade soils of ½-inch to 1-inch. PTS design is based on the potential differential movement of the slabs due to both settlement and heave of the subsoils. Our investigation indicates that predominately low to moderate swelling soils are present at depths likely to influence PTS performance. The following design criteria should be used to construct the PTS foundation. 1. The PTS foundation should be constructed on moisture conditioned, well- compacted fill. Where soil is loosened during excavation or in the forming process, or if any soft or loose soils are exposed in excavations, the soils should be removed or moistened and compacted to the criteria described in Site Development, prior to placing concrete. 2. The PTS should be designed for a maximum allowable soil pressure of 1,500 psf. 3. For the PTI design method, we recommend a differential movement (ym) of 8.6 inches for edge lift conditions and 7.8 inches for center lift conditions as calculated. 4. Based on the 3rd Edition PTI Manual, edge moisture variation distance (em) of 8 feet for the edge condition and 4 feet for the center condition should be used in design. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 10 5. For slab tensioning design, a coefficient of friction value of 0.75 or 1.0 can be assumed for slabs on polyethylene sheeting or a sand layer, respectively. A coefficient of friction of 2.0 should be used for slabs on clay or clay fill. We believe the use of polyethylene is preferable because it serves as a vapor retarder which helps to control moisture migration up through the slabs. 6. A representative of our firm should observe the completed excavations. A representative of the structural engineer or our firm should observe the placement of the reinforcing tendons and reinforcement prior to placing the slabs and beams. Over-Excavation Due to the swell potential of the support soils for the pickleball courts, we recommend moisture treating the upper soil. The over-excavation should extend at least 4 feet below the foundation of the post tensioned pickleball courts and at least 3 feet beyond the perimeter of the footprint of the structure. The existing on-site soils are suitable for re-use as fill material provided debris or deleterious organic materials are removed. Areas to receive fill should be scarified, moisture-conditioned, and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). Clay fill soils placed below the building/pickleball courts should be moisture conditioned between optimum and 3 percent above optimum moisture content. The fill should be moisture conditioned, placed in thin, loose lifts (8 inches or less), and compacted as described above. We should observe placement and test compaction of fill during construction. Fill placement and compaction activities should not be conducted when the fill material or subgrade is frozen. Water-Soluble Sulfates Concrete in contact with soil can be subject to sulfate attack. We measured water- soluble sulfate concentrations of 0.1 percent or less in 6 samples. As indicated in our tests and ACI 318-19, the sulfate exposure class is Not Applicable or S0. Deviations from the exposure class may occur as a result of additional sampling and testing. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 11 SULFATE EXPOSURE CLASSES PER ACI 318-19 Exposure Classes Water-Soluble Sulfate (SO4) in Soil A (%) Not Applicable S0 < 0.10 Moderate S1 0.10 to 0.20 Severe S2 0.20 to 2.00 Very Severe S3 > 2.00 A) Percent sulfate by mass in soil determined by ASTM C1580 For this level of sulfate concentration, ACI 318-19 Code Requirements indicates there are no cement type requirements for sulfate resistance as indicated in the table below. CONCRETE DESIGN REQUIREMENTS FOR SULFATE EXPOSURE PER ACI 318-19 Exposure Class Maximum Water/ Cement Ratio Minimum Compressive Strength (psi) Cementitious Material Types A Calcium Chloride Admixtures ASTM C150/ C150M ASTM C595/ C595M ASTM C1157/ C1157M S0 N/A 2500 No Type Restrictions No Type Restrictions No Type Restrictions No Restrictions S1 0.50 4000 IIB Type with (MS) Designation MS No Restrictions S2 0.45 4500 V B Type with (HS) Designation HS Not Permitted S3 Option 1 0.45 4500 V + Pozzolan or Slag Cement C Type with (HS) Designation plus Pozzolan or Slag Cement C HS + Pozzolan or Slag Cement C Not Permitted S3 Option 2 0.4 5000 V D Type with (HS) Designation HS Not Permitted A) Alternate combinations of cementitious materials shall be permitted when tested for sulfate resistance meeting the criteria in section 26.4.2.2(c). B) Other available types of cement such as Type III or Type I are permitted in Exposure Classes S1 or S2 if the C3A contents are less than 8 or 5 percent, respectively. C) The amount of the specific source of pozzolan or slag to be used shall not be less than the amount that has been determined by service record to improve sulfate resistance when used in concrete containing Type V cement. Alternatively, the amount of the specific source of the pozzolan or slab to be used shall not be less than the amount tested in accordance with ASTM C1012 and meeting the criteria in section 26.4.2.2(c) of ACI 318. D) If Type V cement is used as the sole cementitious material, the optional sulfate resistance requirement of 0.040 percent maximum expansion in ASTM C150 shall be specified. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 12 Superficial damage may occur to the exposed surfaces of highly permeable concrete, even though sulfate levels are relatively low. To control this risk and to resist freeze-thaw deterioration, the water-to-cementitious materials ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to surface drainage or high-water tables. Concrete should have a total air content of 6 percent ± 1.5 percent. Maintenance Routine maintenance, such as sealing and repair of cracks, is necessary to achieve the long-term life of a pavement system. We recommend a preventive maintenance program be developed and 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. A recommended maintenance program is outlined in Appendix F. Excavation of completed pavement for utility construction or repair can destroy the integrity of the pavement and result in a severe decrease in serviceability. To restore the pavement top to original serviceability, careful backfill compaction before repaving is necessary. Surface Drainage A primary cause of premature pavement deterioration is infiltration of water into the pavement system. This increase in moisture content usually results in the softening of base course and subgrade soil and eventual failure of the pavement. In addition, parts of Colorado experience many freeze-thaw cycles each season that can result in deterioration of the pavement. We recommend that subgrade, pavement, and surrounding ground surface be sloped to cause surface water to run off rapidly and away from pavements. Backs of curbs and gutters should be backfilled with compacted fill and sloped to prevent ponding adjacent to backs of curbs and to paving. The final grading of the subgrade should be carefully controlled so the pavement design cross-section can be maintained. Low spots in the subgrade that can trap water should be eliminated. Seals should be provided within the curb and pavement and in all joints to reduce the possibility of water infiltration. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 13 Limitations This report has been prepared for the exclusive use of Old Town Designs, Inc. for the purpose of providing geotechnical design and construction criteria for the proposed project. This report was prepared from data developed during our field exploration, laboratory testing, engineering analysis, and experience with similar conditions. The borings were spaced to obtain a reasonably accurate understanding of the existing pavements and subsurface conditions. The borings are representative of conditions encountered only at the exact boring locations. Variations in subsurface conditions not indicated by our borings are possible. The recommendations contained in this report were based upon our understanding of the planned construction. If plans change or differ from the assumptions presented herein, we should be contacted to review our recommendations. A representative of our firm should observe subgrade preparation and pavement construction. Our representative should also conduct tests of construction materials for compliance with recommendations presented in this report and/or specifications of the controlling agency. Due to the changing nature of site characterization, pavement design methods, standards, and practices, the information and recommendations provided in this report are only valid for one year following the date of issue. Following that time, our office should be contacted to provide, if necessary, any updated recommendations and design criteria as appropriate for the engineering methodologies used at that time. We believe this investigation was conducted in a manner consistent with that level of skill and care ordinarily used by members of the profession currently practicing under similar conditions in the locality of this 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 analysis of the influence of subsurface conditions on design of the pavements, please call. CTL | THOMPSON, INC. by: James Pettus, E.I.T. R.B. “Chip” Leadbetter, III, PE Staff Geotechnical Engineer Senior Geotechnical Engineer TH-1 TH-5 TH-2 TH-3 TH-4 TH-6 HARMONY RD HORSETOOTH RD LE M A Y A V E TI M B E R L I N E R D LEGEND: INDICATES APPROXIMATE LOCATION OF EXPLORATORY BORING TH-1 FIGURE 1 Locations of Exploratory Borings VICINITY MAP (FORT COLLINS, COLORADO) NOT TO SCALE 100'50' APPROXIMATE SCALE: 1" = 100' 0' SITE OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL I T PROJECT NO. FC11440.000-135 APPENDIX A SUMMARY LOGS OF EXPLORATORY BORINGS 0 2 4 6 8 10 0 2 4 6 8 10 12/12 6/12 4/12 WC=15.0DD=115SW=1.3SS=<0.01 WC=23.4DD=101LL=46 PI=31-200=75 TH-1 10/12 7/12 12/12 DD=107 -200=76 DD=107SW=0.8 WC=23.3DD=107LL=61 PI=44-200=76 WC=21.5DD=107SW=0.8SS=<0.01 TH-2 13/12 14/12 7/12 WC=21.3DD=103SW=2.2SS=<0.01 WC=19.7DD=109LL=44 PI=28-200=73 WC=21.3DD=103SW=2.2SS=<0.01 WC=19.7DD=109LL=44 PI=28-200=73 TH-3 12/12 11/12 8/12 WC=16.4DD=114LL=43 PI=27-200=57 WC=15.9DD=113SW=1.7SS=<0.01 WC=16.4DD=114LL=43 PI=27-200=57 WC=15.9DD=113SW=1.7SS=<0.01 TH-4 17/12 6/12 2/12 WC=13.5DD=117SW=3.6SS=0.01 WC=16.9DD=108LL=50 PI=37-200=70 WC=13.5DD=117SW=3.6SS=0.01 WC=16.9DD=108LL=50 PI=37-200=70 TH-5 6/12 9/12 10/12 WC=23.0DD=105LL=48 PI=31-200=68 WC=21.3DD=106SW=2.3SS=<0.01 WC=23.0DD=105LL=48 PI=31-200=68 WC=21.3DD=106SW=2.3SS=<0.01 TH-6 3. CLAY, SANDY, MOIST TO WET, SOFT TO VERY STIFF, BROWN, GREY, BLACK, RUST (CL) ROADBASE ASPHALT LEGEND: FIGURE A-1 WATER LEVEL MEASURED AT TIME OF DRILLING. 2. DRIVE SAMPLE. THE SYMBOL 12/12 INDICATES 12 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES. THE BORINGS WERE DRILLED ON NOVEMBER 15, 2024 USING 4-INCH DIAMETER CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG. NOTES: 1. THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. Summary Logs of Exploratory Borings WC DD SW -200 LL PI SS INDICATES MOISTURE CONTENT (%). INDICATES DRY DENSITY (PCF). INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%). INDICATES PASSING NO. 200 SIEVE (%). INDICATES LIQUID LIMIT. INDICATES PLACTICITY INDEX. INDICATES SOLUBLE SULFATE CONTENT (%). - - - - - - - DE P T H - F E E T DE P T H - F E E T AC=3" AC=3" AC=4" AC=4" ABC=4" ABC=4" ABC=3" ABC=4" OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL | T PROJECT NO. FC11440.000-135 APPENDIX B RESULTS OF LABORATORY TESTING Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT=115 PCF From TH - 1 AT 2 FEET MOISTURE CONTENT=15.0 % Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT=107 PCF From TH - 2 AT 4 FEET MOISTURE CONTENT=21.5 % APPLIED PRESSURE -KSF CO M P R E S S I O N % E X P A N S I O N Swell Consolidation FIGURE B-1 CO M P R E S S I O N % E X P A N S I O N -4 -3 -2 -1 0 1 2 3 TNTAONSER CION UNDSNAPXE GINETTTO WRE DUESSUERP 0.1 10 1001.0 0.1 1.0 10 100APPLIED PRESSURE -KSF -4 -3 -2 -1 0 1 2 3 TNSTAONER CION UNDANSPXE GINTETWTORE DUESSUERP Test ResultsOLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL | T PROJECT NO. FC11440.000-135 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT=103 PCF From TH - 3 AT 2 FEET MOISTURE CONTENT=21.3 % Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT=113 PCF From TH - 4 AT 4 FEET MOISTURE CONTENT=15.9 % APPLIED PRESSURE -KSF CO M P R E S S I O N % E X P A N S I O N Swell Consolidation FIGURE B-2 CO M P R E S S I O N % E X P A N S I O N -4 -3 -2 -1 0 1 2 3 TNTAONSER CION UNDSNAPXE GINETTTO WRE DUESSUERP 0.1 10 1001.0 0.1 1.0 10 100APPLIED PRESSURE -KSF -4 -3 -2 -1 0 1 2 3 TNSTAONER CION UNDANSPXE GINTETWTORE DUESSUERP Test Results OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL | T PROJECT NO. FC11440.000-135 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT=117 PCF From TH - 5 AT 2 FEET MOISTURE CONTENT=13.5 % APPLIED PRESSURE -KSF CO M P R E S S I O N % E X P A N S I O N Swell Consolidation Test Results FIGURE B-3 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 NTNSTANDER COUNSIPAX N OE GTTINE TO WEDUEURERESSP 0.1 1.0 10 100 OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL | T PROJECT NO. FC11440.000-135 Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT=106 PCF From TH - 6 AT 4 FEET MOISTURE CONTENT=21.3 % APPLIED PRESSURE -KSF CO M P R E S S I O N % E X P A N S I O N Swell Consolidation Test Results FIGURE B-4 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 ANTNSTONDER CUNONXPE SIA GETTINUE TO WDERUSSREP 0.1 1.0 10 100 OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL | T PROJECT NO. FC11440.000-135 PASSING WATER- MOISTURE DRY LIQUID PLASTICITY APPLIED NO. 200 SOLUBLE DEPTH CONTENT DENSITY LIMIT INDEX SWELL*PRESSURE SIEVE SULFATES BORING (FEET)(%)(PCF)(%)(PSF)(%)(%)DESCRIPTION S-1 0-5 14.2 55 41 55 CLAY, SANDY (CL) TH-1 2 15.0 115 1.3 150 <0.01 CLAY, SANDY (CL) TH-1 4 23.4 101 46 31 75 CLAY, SANDY (CL) TH-2 2 23.3 107 61 44 76 CLAY, SANDY (CL) TH-2 4 21.5 107 0.8 150 <0.01 CLAY, SANDY (CL) TH-3 2 21.3 103 2.2 150 <0.01 CLAY, SANDY (CL) TH-3 4 19.7 109 44 28 73 CLAY, SANDY (CL) TH-4 2 16.4 114 43 27 57 CLAY, SANDY (CL) TH-4 4 15.9 113 1.7 150 <0.01 CLAY, SANDY (CL) TH-5 2 13.5 117 3.6 150 0.01 CLAY, SANDY (CL) TH-5 4 16.9 108 50 37 70 CLAY, SANDY (CL) TH-6 2 23.0 105 48 31 68 CLAY, SANDY (CL) TH-6 4 21.3 106 2.3 150 <0.01 CLAY, SANDY (CL) SWELL TEST RESULTS* TABLE B-I SUMMARY OF LABORATORY TESTING ATTERBERG LIMITS Page 1 of 1 * NEGATIVE VALUE INDICATES COMPRESSION. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL|T PROJECT NO. FC11440.000-135 APPENDIX C PAVEMENT DESIGN CALCULATIONS Roadway(s): Reliability 75 % Standard Deviation 0.44 Initial Serviceability 4.5 Terminal Serviceability 2 Resilient Modulus 5,356 psi Design ESALs 36,500 Layers Structural Coefficient Drainage Thickness SN HMA 0.44 1 4 1.76 ABC 0.11 1.05 18 2.08 CSS 0.1 1 0 0.00 SUM 3.84 Design Structural Number 2.02 Flexible Structural Design 4401 Innovation Drive Parking Lot OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL|T PROJECT NO. FC11440.000-135 FIGURE C-1 APPENDIX D SAMPLE SITE GRADING SPECIFICATIONS OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 D-1 SAMPLE SITE GRADING SPECIFICATIONS 1. DESCRIPTION This item shall consist of the excavation, transportation, placement, and compaction of materials from locations indicated on the plans, or staked by the Engineer, as necessary to achieve site elevations. 2. GENERAL The Soils Engineer shall be the Owner's representative. The Soils Engineer shall approve fill materials, method of placement, moisture contents, and percent compaction, and shall give written approval of the completed fill. 3. CLEARING JOB SITE The Contractor shall remove all trees, brush, and rubbish before excavation or fill placement is begun. The Contractor shall dispose of the cleared material to provide the Owner with a clean, neat appearing job site. Cleared material shall not be placed in areas to receive fill or where the material will support structures of any kind. 4. SCARIFYING AREA TO BE FILLED All topsoil and vegetable matter shall be removed from the ground surface upon which fill is to be placed. The surface shall then be plowed or scarified to a depth of 8 inches until the surface is free from ruts, hummocks, or other uneven features, which would prevent uniform compaction by the equipment to be used. 5. COMPACTING AREA TO BE FILLED After the foundation for the fill has been cleared and scarified, it shall be disked or bladed until it is free from large clods, brought to the proper moisture content and compacted to not less than 95 percent of maximum density as determined in accordance with ASTM D 698. 6. FILL MATERIALS Materials classifying as CL, SC, SM, SW, SP, GP, GC, and GM are acceptable. Fill soils shall be free from organic matter, debris, or other deleterious substances, and shall not contain rocks or lumps having a diameter greater than three (3) inches. 7. MOISTURE CONTENT Fill materials shall be moisture treated. Clay soils should be moisture-treated to between optimum and 3 percent above optimum moisture content as determined from Standard Proctor compaction tests. Sand soils should be moistened to within 2 percent optimum moisture content. Sufficient laboratory compaction tests shall be made to determine the optimum moisture content for the various soils encountered in borrow areas. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 D-2 The Contractor may be required to add moisture to the excavation materials in the borrow area if, in the opinion of the Soils Engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. The Contractor may be required to rake or disk the fill soils to provide uniform moisture content through the soils. The application of water to embankment materials shall be made with any type of watering equipment approved by the Soils Engineer, which will give the desired results. Water jets from the spreader shall not be directed at the embankment with such force that fill materials are washed out. Should too much water be added to any part of the fill, such that the material is too wet to permit the desired compaction from being obtained, rolling, and all work on that section of the fill shall be delayed until the material has been allowed to uniformly dry to the required moisture content. The Contractor will be permitted to rework wet material in an approved manner to hasten its drying. 8. COMPACTION OF FILL AREAS Selected fill material shall be placed and mixed in evenly spread layers. After each fill layer has been placed, it shall be uniformly compacted to not less than the specified percentage of maximum density. Fill materials shall be placed such that the thickness of loose material does not exceed 8 inches and the compacted lift thickness does not exceed 6 inches. Compaction, as specified above, shall be obtained by the use of sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or other equipment approved by the Engineer. Compaction shall be accomplished while the fill material is at the specified moisture content. Compaction of each layer shall be continuous over the entire area. Compaction equipment shall make sufficient trips to ensure that the required density is obtained. 9. COMPACTION OF SLOPES Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until slopes are stable, but not too dense for planting, and there is no appreciable amount of loose soil on the slopes. Compaction of slopes may be done progressively in increments of three to five feet (3' to 5') in height or after the fill is brought to its total height. Permanent fill slopes shall not exceed 3:1 (horizontal to vertical). 10. DENSITY TESTS Field density tests shall be made by the Soils Engineer at locations and depths of his choosing. Where sheepsfoot rollers are used, the soil may be disturbed to a depth of several inches. Density tests shall be taken in compacted material below the disturbed surface. When density tests indicate that the density or moisture content of any layer of fill or portion thereof is below that required, the particular layer or portion shall be reworked until the required density or moisture content has been achieved. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 D-3 11. COMPLETED PRELIMINARY GRADES All areas, both cut and fill, shall be finished to a level surface, and shall meet the following limits of construction: a. Overlot cut or fill areas shall be within plus or minus 2/10 of one foot. b. Street grading shall be within plus or minus 1/10 of one foot. The civil engineer, or duly authorized representative, shall check all cut and fill areas to observe that the work is in accordance with the above limits. 12. SUPERVISION AND CONSTRUCTION STAKING Observation by the Soils Engineer shall be continuous during the placement of fill and compaction operations so that he can declare that the fill was placed in general conformance with specifications. All site visits necessary to test the placement of fill and observe compaction operations will be at the expense of the Owner. All construction staking will be provided by the Civil Engineer or his duly authorized representative. Initial and final grading staking shall be at the expense of the owner. The replacement of grade stakes through construction shall be at the expense of the contractor. 13. SEASONAL LIMITS No fill material shall be placed, spread, or rolled while it is frozen, thawing, or during unfavorable weather conditions. When work is interrupted by heavy precipitation, fill operations shall not be resumed until the Soils Engineer indicates that the moisture content and density of previously placed materials are as specified. 14. NOTICE REGARDING START OF GRADING The contractor shall submit notification to the Soils Engineer and Owner advising them of the start of grading operations at least three (3) days in advance of the starting date. Notification shall also be submitted at least 3 days in advance of any resumption dates when grading operations have been stopped for any reason other than adverse weather conditions. 15. REPORTING OF FIELD DENSITY TESTS Density tests made by the Soils Engineer, as specified under "Density Tests" above, shall be submitted progressively to the Owner. Dry density, moisture content, of each test taken, and percentage compaction shall be reported for each test taken. 16. DECLARATION REGARDING COMPLETED FILL The Soils Engineer shall provide a written declaration stating that the site was filled with acceptable materials or was placed in general accordance with the specifications. APPENDIX E PAVEMENT CONSTRUCTION RECOMMENDATIONS OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 E-1 SUBGRADE PREPARATION Moisture Treated Subgrade (MTS) 1. The subgrade should be stripped of organic matter, scarified, moisture treated and compacted to the specifications stated below in Item 2. The compacted subgrade should extend at least 3 feet beyond the edge of the pavement where no edge support, such as curb and gutter, are to be constructed. 2. Sandy and gravelly soils (A-1-a, A-1-b, A-3, A-2-4, A-2-5, A-2-6, A-2-7) should be moisture conditioned near optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). Clayey soils (A-6, A-7-5, A-7-6) should be moisture conditioned between optimum and 3 percent above optimum moisture content and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). 3. Utility trenches and all subsequently placed fill should be properly compacted and tested prior to paving. As a minimum, fill should be compacted to 95 percent of standard Proctor maximum dry density. 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. 5. Once final subgrade elevation has been compacted and tested to compliance and shaped to the required cross-section, the area should be proof-rolled using a minimum axle load of 18 kips per axle. The proof-roll 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. 6. Areas that are observed by the Engineer that have soft spots in the subgrade, or where deflection is not uniform of soft or wet subgrade shall be ripped, scarified, dried or wetted as necessary and recompacted to the requirements for the density and moisture. As an alternative, those areas may be sub-excavated and replaced with properly compacted structural backfill. Where extensively soft, yielding subgrade is encountered; we recommend a representative of our office observe the excavation. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 E-2 PAVEMENT MATERIALS AND CONSTRUCTION Aggregate Base Course (ABC) 1. A Class 5 or 6 Colorado Department of Transportation (CDOT) specified ABC should be used. Reclaimed asphalt pavement (RAP) or reclaimed concrete pavement (RCP) alternative which meets the Class 5 or 6 designation and design R-value/strength coefficient is also acceptable. 2. Bases should have a minimum Hveem stabilometer value of 78, or greater. ABC, RAP, and RCP must be moisture stable. The change in R-value from 300-psi to 100-psi exudation pressure should be 12 points or less. 3. ABC, RAP or RCP bases should be placed in thin lifts not to exceed 6 inches and moisture treated to near optimum moisture content. Bases should be moisture treated to near optimum moisture content, and compacted to at least 95 percent of modified Proctor maximum dry density (ASTM D 1557, AASHTO T 180) standard Proctor maximum dry density (ASTM D 698, AASHTO T 99). 4. Placement and compaction of ABC, RAP, or RCP should be observed and tested by a representative of our firm. Placement should not commence until the underlying subgrade is properly prepared and tested. Hot Mix Asphalt (HMA) 1. HMA 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 up to 20 percent 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. 2. HMA should be relatively impermeable to moisture and should be designed with crushed aggregates that have a minimum of 80 percent of the aggregate retained on the No. 4 sieve with two mechanically fractured faces. 3. Gradations that approach the maximum density line (within 5 percent between the No. 4 and 50 sieves) should be avoided. A gradation with a nominal maximum size of 1 or 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 percent. The mixture should have a minimum VMA of 14 percent and between 65 percent and 80 percent of voids filled. 5. Asphalt cement should meet the requirements of the Superpave Performance Graded (PG) Binders. The minimum performing asphalt cement should conform to the requirements of the governing agency. OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 E-3 6. Hydrated lime should be added at the rate of 1 percent 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. Paving should be performed on properly prepared, unfrozen surfaces that are free of water, snow, and ice. Paving should only be performed when both air and surface temperatures equal, or exceed, the temperatures specified in Table 401- 3 of the 2023 Colorado Department of Transportation Standard Specifications for Road and Bridge Construction. 8. HMA should not be placed at a temperature lower than 245oF for mixes containing PG 64-22 asphalt, and 290oF for mixes containing polymer-modified asphalt. The breakdown compaction should be completed before the HMA temperature drops 20oF. 9. Wearing surface course shall be Grading S or SX for residential roadway classifications and Grading S for collector, arterial, industrial, and commercial roadway classifications. 10. The minimum/maximum lift thicknesses for Grade SX shall be 1½ inches/2½ inches. The minimum/maximum lift thicknesses for Grade S shall be 2 inches/3½ inches. The minimum/maximum lift thicknesses for Grade SG shall be 3 inches/5 inches. 11. Joints should be staggered. No joints should be placed within wheel paths. 12. HMA 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 185oF. 13. Placement and compaction of HMA should be observed and tested by a representative of our firm. Placement should not commence until approval of the proof rolling as discussed in the Subgrade Preparation section of this report. Sub-base, base course or initial pavement course shall be placed within 48 hours of approval of the proof rolling. If the Contractor fails to place the sub-base, base course or initial pavement course within 48 hours or the condition of the subgrade changes due to weather or other conditions, proof rolling and correction shall be performed again. APPENDIX F MAINTENANCE PROGRAM OLD TOWN DESIGNS, INC. 4401 INNOVATION DRIVE, FORT COLLINS CTL  T PROJECT NO. FC11440.000-135 F-1 MAINTENANCE RECOMMENDATIONS FOR FLEXIBLE PAVEMENTS A primary cause for deterioration of 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 should be performed each spring or fall. b. Reports documenting the progress of distress should be kept current to provide information on effective times to apply preventive maintenance treatments. c. Crack sealing should 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 life, at least one major corrective overlay should be expected.