203.01 203-1 SECTION 203 EXCAVATION AND EMBANKMENT DESCRIPTION
203.01 General. This work consists of excavation, hauling, disposal, placement, and
compaction of all material encountered within the limits of the work, including construction of dikes and excavation for ditches and channels, necessary for the construction of the roadway per the Contract. MATERIALS
203.02 Excavation Definitions . All excavation will be defined as, “unclassified excavation”,
“stripping”, “removal of unsuitable material”, “rock excavation”, “borrow”, or “potholing” as described below:
a.Unclassified Excavation . Unclassified excavation shall consist of the excavation of all materials of whatever character required for the work, obtained within the right of way, including surface boulders and excavation for ditches and channels that is not removed under some other item.
b.Stripping . Stripping shall consist of removing overburden or other specified material from borrow pits, and the replacement of overburden or other specified material over the disturbed area of the site or pit after the underlying material has been removed.
c.Removal of Unsuitable Material . Removal of unsuitable material shall consist of the removal of soils or mixtures of soil and organic matter identified in the Contract or as directed by the Engineer that would be detrimental to the roadway or embankment if left in place in its existing condition.
d.Rock Excavation . Rock excavation shall consist of removal of igneous, metamorphic, and sedimentary rock that cannot be excavated without blasting or with the use of rippers, including all boulders or other detached stones having a volume of 1/2 cubic yard or more. Unless specified in the Contract, rock excavation is material that meets one of the following field test criteria to be conducted by the Contractor:
1.Ripping Test: Material that cannot be broken down by one pass with a single tooth ripper mounted on a crawler type tractor in low gear with a minimum net flywheel power rating of 235 horsepower; or material that cannot be broken down with a 48,000- pound tracked excavator using a bucket with rock teeth.
2.Seismic Test: Material that has a seismic velocity of 6,000 feet per second or greater. The Contractor shall submit the qualifications of the individual performing or interpreting the seismic testing to the Engineer a minimum of 14 days before testing. The ripping test will be used to resolve differences if seismic velocities fall below 6,000 feet per second.
3.Handling Test: Any boulder or detached stone having a volume of ½ -cubic yard or more that cannot be readily broken down with the excavation equipment described above in 1.
e.Borrow . Borrow shall consist of approved material obtained from outside the right of way required for the construction of the project. 203.03 203-2 (f) Potholing . Potholing shall consist of exposing and verifying the location of existing utilities at locations as directed.
203.03 Embankment Material . Embankment material shall consist of approved material
acquired from excavations or borrow pits and hauled and placed in embankments. Approval of embankment material is contingent on the material meeting the Atterberg Limit and gradation requirements specified in the Contract. Approval of the embankment material in the upper 2 feet of embankment below the subgrade elevation is contingent on the material meeting one of the following as specified in the Contract:
1.The specified resistance value when tested by the Hveem Stabilometer or the equivalent resilient modulus.
2.The specified Atterberg Limit and gradation requirements.
3.The specified resistance value when tested by the Hveem Stabilometer or equivalent resilient modulus, and the specified Atterberg Limit and gradation requirements. Embankment material shall be classified into one of the material groups listed below and placed and compacted per the appropriate methods specified in subsection 203.07. If any material does not meet the criteria for one of the following classifications, it shall be processed on site to meet the requirements for one of the material groups listed below or disposed of at the Contractor’s expense.
1.Soil Embankment : Soil embankment shall have all particle sizes less than 6 inches. The material shall be classified per AASHTO M 145 and placed and compacted per subsection 203.07(a).
2.Rock Embankment : Rock embankment shall meet all of the following requirements:
A.A minimum of 50 percent of the material shall be retained on the 4.75 mm (No. 4) sieve.
B.More than 30 percent of the material shall be retained on the 19.0 mm (3/4- inch) sieve.
C.The material shall meet the classification of an AASHTO A -1 soil type.
D.All particle sizes shall be less than 6 inches.
E.Particles retained on the 4.75mm (No. 4) sieve shall not be composed of non - durable bedrock types. Rock embankment may be placed without moisture density control as described in subsection 203.07(b).
3.Rock Fill: Rock fill shall meet all of the following requirements:
A.A minimum of 50 percent of the material shall be retained on a 100 mm (4 -inch) sieve.
B.The maximum dimension of any particle shall not exceed 36 inches.
C.The material shall be well -graded as determined on visual inspection.
D.The material shall contain less than 20 percent by volume of material passing the 75 μm (No. 200) sieve based on visual inspection. 203.03 203-3 E. Particles retained on the 4.75 mm (No. 4) sieve shall not be composed of non -durable bedrock types. Rock fill can be placed without moisture density control as described in subsection 203.07(b). Non-durable bedrock shall be identified and classified using Colorado Procedure - Laboratory (CP-L) 3104. Any material classified as Soil -like Non -durable (S -N) as defined in the procedure shall be pulverized, broken down and processed to 6 -inch maximum particle sizes before incorporation into embankment fill. These materials shall be placed and compa cted as “soil embankment” per subsection 203.07(a). Non -durable bedrock particles in excess of 6 inches shall not be placed into embankment fill. If recycled concrete or asphalt are to be incorporated into embankment fill, the maximum dimension permitted for concrete is 24 inches and the maximum dimension permitted for asphalt is 12 inches. Embankment material imported onto the project will be tested for water soluble sulfates u sing CP -L 2103 Method B. The average of three consecutive tests shall show that the sulfate content is not greater than that corresponding to the sulfate exposure level specified in the Contract. No single test shall have a sulfate content more than 20 percent greater than that corresponding to the sulfate exposure level specified in the Contra ct. When there is a single failing test, the remaining sample shall be split into four equal portions. The CDOT Region Lab shall receive one portion, the Contractor shall receive one portion, and the remaining two portions shall go to the CDOT Central Lab . The CDOT Region Lab, the CDOT Central Lab, and the Contractor’s Lab shall retest the sample. If the results from the three labs are within 10 percent of each other, the results will be averaged. The averaged result will be used for determining Contract compliance. If the results from the labs are not within 10 percent of each other, the remaining split sample shall be sent to an independent laboratory for testing using CP -L 2103. The independent laboratory shall be mutually agreed upon by the Department and the Contractor. The independent lab’s test result will be use d for determining Contract compliance. If the water -soluble sulfate content is less than that corresponding to the sulfate exposure level specified in the Contract, CDOT will bear all costs associated with the independent lab test. If the soluble sulfate content is greater than that corresponding to the sulfate exposure level specified in the Contract, all costs associated with independent lab testing shall be at the Contractor’s expense. Embankment represented by failing tests shall be removed from the project and replaced at the Contractor’s expense. Imported material used for backfilling pipes (storm sewer, cross culverts, side drains, etc.) shall be tested for compatibility with the selected pipe material. When non -reinforced concrete pipe or reinforced concrete pipe is used, the imported material shall be tested for sulfate and pH. When corrugated steel pipe, bituminous -coated corrugated steel pipe or pre -coated corrugated steel pipe is used, the imported material shall be tested for sulfates, chlorides, pH and resistivity. When aramid fiber bonded corrugated steel pipe or corrugated aluminum pipe is used, the imported material shall be tested for pH and resistivity. When plastic pipe is selected, the imported material does not need to be tested for sulfates, chlorides, pH or resistivity. 203.03 203-4 Sulfates, chlorides, pH and resistivity shall be determined by the following procedures:
1.Water soluble sulfate s using CP -L 2103 Method B
2.Chloride s using CPL 2104
3.Resistivity using ASTM G57
4.pH using ASTM G51 The average of three consecutive tests shall show the imported material’s sulfate, chloride, pH and resistivity is not greater than the limits corresponding to the Pipe Class in Table 203 -1 or 203- 2 for the pipe class specified in the Contract. No single test shall have a result more than 20 percent greater than that corresponding to the limit in Table 203 -1 or Table 203 -2 for sulfates, chlorides and resistivity. No single test shall have a result more than 5 percent outside the limit in Table 203 -1 for pH. The remaining sample material from a single failing test shall be split into three equal portions. CDOT shall receive one portion, the Contractor shall receive one portion and the remaining por tion shall be retained by the Project. CDOT and the Contractor’s Lab shall retest the failed sample; if the results from those tests are within 10 percent of each other, the results will be averaged. The averaged result will be used for Contract complian ce. If the results from the Labs are not within 10 percent of each other, the remaining sample portion shall be sent to an independent laboratory for testing using the testing requirements specified above. The independent laboratory shall be mutually agreed upon by the Department and the Contractor. The Independent Lab’s test result will be used for Contract compliance. If the imported material’s sulfates, chlorides, and resistivity are less than the limits and the pH is within the limits in Table 203 -1 or 203- 2, CDOT will bear all costs associated with the independent lab test. If the imported material’s sulfates, chlor ides, and resistivity is greater than the limits and the pH is outside the limits in Table 203 -1 or 203- 2, all costs associated with independent lab testing shall be at the Contractor’s expense. Embankment represented by failing tests shall be removed from the project and replaced at the Contractor’s expense. Table 203-1 SULFATE, CHLORIDE AND pH OF IMPORTED MATERIAL Pipe Class Soil Sulfate (SO4) % max. Soil Chloride (Cl) % max. Soil pH 0, 7 0.05 0.05 6.0-8.5 1, 7 0.1 0.1 6.0-8.5 2, 8 0.2 0.2 6.0-8.5 3, 9 0.5 0.5 6.0-8.5 4, 9 1 1 5.0-9.0 5, 10 2 2 5.0-9.0 6, 10 >2.00 >2.00 <5 or >9 203.04 203-5 Table 203 -2 RESISTIVITY AND pH OF IMPORTED MATERIAL SOIL SIDE Resistivity R (Ohm – cm) SOIL SIDE pH ≥ 1500 5.0-9.0 ≥ 250 3.0-12.0 CONSTRUCTION REQUIREMENTS
203.04 General. The excavations and embankments shall be finished to smooth and uniform
surfaces conforming to the typical sections specified. Variation from the subgrade plan elevations specified shall not be more than 0.08 foot. Where asphalt or concrete surfacing materials are to be placed directly on the subgrade, the subgrade plane shall not vary more than 0.04 foot. Materials shall not be wasted without written permission of the Engineer. Excavation operations shall be conducted so material outside of the slope limits will not be disturbed. Before beginning grading operations, all necessary clearing and grubbing in that area shall have been performed per Section 201. The Contractor shall notify the Engineer at least five workdays before beginning excavation. The Contractor shall not excavate beyond the dimensions and elevations shown in the Contract. Archaeological and paleontological materials encountered during the work shall be handled per subsection 107.23. All excavation activities in areas where asbestos is encountered or expected to be encountered shall conform to the Colorado Department of Public Health and Environment’s Asbestos - Contaminated Soil Guidance Document or the State of Colorado’s Asbestos Contaminated Soil Statewide Management Plan (ACS), whichever is more recent at the time of advertisement and per subsection 250.07(d) and the Air Quality Control Commission Regulation No. 8 Part B or Section 5.5 of the solid Waste Regulation 6 CCR 1007 -2, as applicable.
203.05 Excavation . Excavation shall be one or more of the following:
a.Rock. Unless otherwise specified, rock shall be excavated to a minimum depth of 0.5 foot and a maximum depth of 1 foot below subgrade, within the limits of the roadbed. Rock removed in excess of 1 foot below subgrade will not be paid for. Backfilling of the depth in excess of 1 foot below subgrade shall be at the Contractor’s expense. Approved embankment material shall be used to bring the rock -excavated areas to subgrade elevations within the tolerances specified in subsection 203.04. Undrained pockets shall not be left in the rock surface and depressions shall be drained at the Contractor’s expense. When required for rock excavation, controlled blasting shall be conducted per the Contract.
b.Unclassified. Excess or unsuitable excavated material, including rock and boulders, that cannot be used in embankments may be placed on the side slopes of the nearest fill if approved. 203.06 203-6 Unless otherwise specified by the Engineer , intercepting ditches shall be made above the top of cut slopes and carried to outlets near the ends of the cuts. In order to blend the intersection of cut slopes with the slope of the adjacent natural ground surfaces in a uniform manner, the tops of all cut slopes, except those in solid rock, shall be flattened and rounded per typical sections and details specified. Earth overburden lying above solid rock cuts shall be treated in the same manner as earth cuts. The Department reserves the right to change cut slopes during the progress of excavation.
c.Unsuitable Material . Unsuitable materials encountered in the subgrade, roadway, or embankment foundation that are determined to be detrimental to the roadway or embankment shall be removed to the depth and extents directed by the Engineer. The excavated area shall be backf illed to the finished graded section with approved material. Materials that contain organics or that cannot be dried or moisture conditioned, then compacted to the required density shall be disposed of and shall not be reused as embankm ent fill. Materials that do not contain organics and that can be dried or moisture conditioned and compacted to the required density may be reused as embankment fill as approved by the Engineer.
d.Borrow . If the Contractor places more borrow than is specified or approved and causes a waste of roadway excavation, the quantity of waste will be deducted from the borrow volume. All borrow areas shall be bladed and shaped to permit accurate measurements after excavation is completed. The finished borrow areas shall be graded to a smooth and uniform surface and shall be finished so water will not collect or stand, unless otherwise specified.
e.Stripping . Overburden shall be removed to the depth required for the production of acceptable material, and at least 5 feet beyond area being excavated.
f.Potholing . All necessary potholing as determined by the Contractor and agreed to by the Engineer shall be completed under this item with appropriate equipment as approved. The Contractor shall acquire necessary permits, locate utilities, excavate all materials of whatever character required to expose the utilities, survey the location of the utilities, and backfill the excavation to existing grade lines with the excavated or other approved materials. Backfilling shall be accomplished per subsection 206.03. The Contractor shall use extreme caution during this work. All damage to existing utility lines or adjacent facilities shall be repaired promptly at the Contractor’s expense.
203.06 General Embankment Construction Requirements . When Contractor Process
Control is required, the Contractor’s Process Control Representative shall be certified with Western Alliance for Quality Transportation Construction (WAQTC ) Embankment and Base Testing and CDOT’s Excavation, Embankment, and Soil Inspection certification course. Embankment construction shall include preparation of the areas where embankments are to be placed, construction of dikes, and placing and compacting approved material within roadway areas including holes, pits, and other depressions within the roadway area. Only approved materials shall be used in the construction of embankments and fills. 203.07 203-7 All sod, vegetable and other organic matter , stumps, and roots shall be removed from the surface where the embankment is to be placed per Section 201. Unless a thickness is otherwise specified in the Contract, the upper 4 inches of the ground surface will be considered topsoil and shall be removed per Section 207 before placement of embankment fill. The cleared surface shall be completely broken up by plowing or scarifying to a minimum depth of 6 inches or as specified in the Contract, the moisture content increased or reduced as necessary, and compacted to the specified embankment density for the material type present. When embankment is placed on a slope that is steeper than 4H:1V , as measured in the steepest direction, the existing slope shall be benched as the embankment is placed in layers. A 2-foot- deep key shall be excavated at the base of the existing slope and backfilled with approved and compacted material. The embankment shall be placed in layers from that key. Each horizontal cut shall begin at the intersection of the original ground and the vertical sides of the previous bench. Excavated material from benc hing may be placed and compacted with the embankment material at the Contractor’s expense. During the course of construction, embankment side slopes shall be built a minimum of 12 inches wider than the final grade indicated in the Contract to allow for compaction equipment to compact the full width of the embankment. Once the specified level of compaction is achieved, the side slopes shall be trimmed back to final grade. Excess material placement and removal to satisfy this requirement shall be at the Contractor’s expense. If embankment can be placed on only one side of structures such as retaining walls, abutments, wing walls, piers, or culvert headwalls, compaction shall be accomplished without initiating movement or deformation of the structure and without placing excessi ve pressure against the structure. When noted in the Contract, the fill adjacent to the abutment of a bridge shall not be placed higher than the bottom of the backwall until the superstructure is in place. When embankment is placed on both sides of a con crete wall or box type structure, the embankment shall be brought up equally on both sides of the structure. Where embankment is to be placed and compacted and end dumping is used, the slopes of the original ground or embankment shall be deeply plowed or scarified before starting end dumping. Embankment fill other than A -1 soil types shall not be placed within standing water, unless otherwise noted in the Contract. During the construction of the embankment, the top surface shall be maintained so that it is well drained at all times. Frozen materials shall not be used in construction of embankments. Frozen material will be identified by the visual observation of ice crystals within the foundation or embankment material, or by measuring the temperature of the ground surface.
203.07 Embankment Placement and Compaction Requirements . Materials incorporated into
embankment fill shall be placed and compacted according to the following requirements:
a.Soil Embankment. All soil embankment shall be placed in horizontal layers not to exceed 8 inches in loose lift thickness. Each layer shall be compacted before the placement of subsequent layers. Spreading equipment shall be used to obtain uniform thickness before compaction. As the compaction progresses, continuous mixing, leveling, and manipulating shall be done to assure uniform moisture and density. Additional work involved in drying soil embankment to the required moisture content shall be included in the contract price paid for excavating or furnishing the material with no additional compensation. 203.07 203-8 Soil embankment that is classified as A -1 material may be used to bridge across standing water or swampy ground within the embankment foundation and may be placed in lift thicknesses greater than 8 inches when used for this purpose if approved by the Engineer. Soil embankment with less than or equal to 30 percent retained on the 3/4 -inch sieve shall be tested for compaction using CP 80. Materials classified as AASHTO A -1, A-2-4, A- 2-5, and A -3 soils shall be compacted at plus or minus 2 percent of Optimum Moisture Content (OMC) and to at least 95 percent of maximum dry density determined per AASHTO T 180 as modified by CP 23. All other soil types shall be compacted to 95 percent of the maximum dry density determined per AASHTO T 99 as modified by CP 23. Soils with 35 percent fines or less shall be compacted at plus or minus 2 percent of OMC. Soils with greater than 35 percent fines shall be compacted at a moisture content equal to or above OMC to achieve stability of the compacted lift. Stability is defined as the absence of rutting or pumping as observed and documented by the Contractor’s Process Control Representative and as approved by the Engineer. If the soils cannot be compacted and prove to be unstable at a moisture content equal to or above OMC, then the required moisture content for compaction may be reduced below OMC if approved by the Engineer. Before placing any soil embankment with greater than 30 per cent retained on the 3/4 - inch sieve, the Contractor shall construct a test strip to the dimensions specified in the Contract or as directed by the Engineer. The test strip may be incorporated into the final embankment. The Contractor shall determine the moisture conditioning ne cessary to achieve compaction and shall determine the equipment and number of passes necessary to achieve adequate compaction. The Contractor shall use compression -type or vibratory rollers on granular materials and sheepsfoot rollers on cohesive soils. Adequate compaction shall be demonstrated by the absence of rutting, pumping, or deflection following a proof roll of the test strip using any piece of construction equipment that exerts a minimum 18 -kip per axle load. The proof roll will be observed and accepted by the Engineer. Once the test strip passes a proof roll, the Contractor may resume embankment construction using the same moisture conditioning and compaction methods that were used to construct the test strip. Placement, moisture conditioning, and compaction of every lift of soil embankment with greater t han 30 percent retained on the 3/4 -inch sieve shall be observed by the Contractor’s Process Control Representative and accepted by the Engineer . Adequate compaction of each lift shall be demonstrated as the absence of rutting, pumping, or deflection as construction equipment is routed over a lift following the compactive efforts that were used and accepted for the respective test strip. The Eng ineer may request a proof roll at any time to document the condition of a lift. Significant changes in the material being hauled for soil embankment with greater t han 30 percent retained on the 3/4 -inch sieve will require construction of a new test strip, and demonstration of adequate compaction methods using a proof roll. Non-durable bedrock shall be watered to promote slaking and break down and pulverized or processed to a maximum particle size of 6 inches. These materials shall be placed and compacted as soil embankment; except they shall be compacted with a heavy tamping foot roller weighing at least 30 tons. Each tamping foot shall protrude from the drum a minimum of 4 inches. Each embankment layer shall receive a minimum of four passes with the tamping foot roller. 203.07 203-9 The roller shall be operated at a uniform speed not exceeding 3 miles per hour. No additional compensation will be made for additional roller passes to achieve specified density requirements. Non-durable Bedrock shall not be used to bridge over standing water or swampy ground within an embankment foundation. Non -durable bedrock shall also not be placed within 2 feet of the final subgrade elevation.
b.Rock Embankment and Rock Fill. Rock embankment shall be placed in horizontal layers not to exceed 8 inches in loose lift thickness. The lift thickness can be increased when bridging over standing water or swampy ground in the embankment foundation as directed by the Engineer. Each lay er shall be compacted before the placement of subsequent layers. Spreading equipment shall be used to obtain uniform thickness before compaction. Rock fill shall be placed in horizontal layers not to exceed a loose lift thickness equivalent to the average particle size up to a maximum permitted lift thickness of 18 inches. Particles with a maximum dimension of 36 inches are permitted; however, rock s larger than the lift thickness shall be separated enough to allow compaction equipment to operate in between. Material shall be placed to fill in voids between larger stones with finer particle sizes and to avoid nesting. Spreading equipment shall be u sed to obtain uniform thickness before compaction. If the use of leveling equipment is not practical, the Engineer may permit rock fill material to be cast or end dumped. In such cases sufficient hand or machine work will be required to construct a compact, stable fill and to finish the slop es to a neat and smooth appearance. Rock fill shall not be placed within 2 feet of the final subgrade elevation. When a rock fill is placed over any structure, the structure shall be covered with a minimum of 2 feet of compacted soil embankment or rock embankment material before the rock fill is placed. The Contractor shall determine the moisture conditioning necessary to achieve compaction for rock embankment or rock fill. Vibratory or compression -type rollers shall be used to compact these materials. At a minimum, compression -type rollers weighing 20 tons shall complete four passes over the entire width of a lift at a speed not to exceed 3 miles per hour. Vibratory rollers shall exert a minimum dynamic force of 30,000 pounds of impact per vibration and achieve a minimum 1,000 vibrations per minute. Vibratory rollers shall complete a minimum of four passes over the entire width of a lift at a speed not to exceed 1.5 miles per hour. Before placing rock embankment or rock fill, the Contractor shall construct a test strip to the dimensions specified in the Contract, or as directed by the Engineer. The test strip may be incorporated into the final embankment. Adequate compaction of the rock embankment or rock fill test strip shall be demonstrated by the absence of rutting, pumping, or deflection following a proof roll of the test strip using any piece of construction equipment that exerts a minimum 18 -kip per axle load. The proof roll will be observed and accepted by the Engineer. Once the test strip passes a proof roll, the Contractor can resume rock embankment or rock fill construction with the same moisture conditioning and compaction methods as the test strip was constructed. Plac ement, moisture conditioning, and compaction of every lift of rock embankment and rock fill shall be observed by the Contractor’s Process Control Representative and accepted by the Engineer. Adequate compaction of each lift shall be demonstrated as the ab sence of rutting, pumping, or 203.08 203-10 deflection as construction equipment is routed over a lift following the compactive efforts that were used and accepted for the respective test strip. The Engineer may request a proof roll at any time to document the condition of a lift. Significant changes in the characteristics of material being hauled for rock embankment or rock fill will require construction of a new test strip, and demonstration of adequate compaction methods using a proof roll. If the Contractor wishes to deviate from the minimum equipment and compactive efforts specified above for rock embankment or rock fill, the Contractor must first demonstrate the adequacy of the proposed methods with a test strip and passing proof roll. In addition, proof rolls are required for every lift placed for the first 2,000 cubic yards of rock embankment or rock fill placed. The proof rolls used to demonstrate adequate compaction of the first 2,000 cubic yards placed will not be measured and paid f or separately but shall be performed at the Contractor’s expense.
c.Use of Recycled Concrete and Asphalt . Recycled concrete and asphalt may be incorporated into embankment material, and shall be processed, placed, and compacted per subsection 203.07(a) or (b), depending on the overall classification of the embankment material once the recycled material is incorporated. Rebar shall not extend more than one inch beyond the edges of recycled concrete particles. Recycled concrete or asphalt shall not be placed in the upper 2 feet of the final subgrade elevation or within 2 feet of the final finished side slopes unless otherwise noted in the Contract.
203.08 Proof Rolling . Proof rolling with pneumatic tire equipment shall be performed
using a minimum axle load of 18 kips per axle. A weigh ticket from an approved scale shall be furnished by the Contractor to substantiate this weight. The subgrade shall be proof rolled after the required compaction has been obtained and the subgrade has been shaped to the required cross section. The proof roller shall be operated in a systematic manner so that a record may be readily kept of the area tested and the working time required for the testing. Areas that are observed to have soft spots in the subgrade, where deflection is not uniform or is excessive as determined by the Engineer, shall be ripped, scarified, dried or wetted as necessary, and re-compacted to the requirements for density and moisture at the Contractor’s expense. After re -compaction, these areas shall be proof rolled again and all failures again corrected at the Contractor’s expense. Upon approva l of the proof rolling, the sub base, base course, or initial pavement course shall be placed within 48 hours. If the Contractor fails to place the subbase, 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 at the Contractor’s expense.
203.09 Blading .
Blading shall consist of furnishing motor graders of the specified horsepower rating, with operators, for shaping roadway, shoulders, or other areas as designated by the Engineer. When scarifying is specified, the motor grader shall be equipped with an independently operated “V” type scarifier and attachments. 203.10 203-11 203.10 Dozing . Dozing shall consist of furnishing crawler -type tractors of the specified horsepower rating, complete with operators and bulldozer blades. Rippers, if specified, will not be measured and paid for separately, but shall be included in the work. METHOD OF MEASUREMENT
203.11 Items paid for by volume be the quantities designated in the Contract. Exceptions will
be made when field changes are ordered or when it is determined that there are discrepancies in the Contract in an amount of at least plus or minus two percent of the p lan quantity.
a.Excavation . The original cross -sections will be used for determination of volumes of excavated material removed, unless changes have been directed. These measurements will include authorized excavation of rock, shale, or other unsuitable material. All accepted stripping will be measured in stockpiled locations by cross -sectioning. When the excavation conforms to the staked lines and grades, the original cross -sections and the staked sections shall be used for the determination of volumes excavated. Volumes will be computed from the cross -sections by the average end area or other acceptable method. When topsoil or wetland topsoil is included as a separate pay item and is specified, the measured volume of excavation will be reduced by the volume of topsoil or wetland topsoil removed from the area shown as excavation in the Contract. Measurements will include over -breakage in rock excavation from the back slopes to an amount not to exceed, in any half station of 50 feet, 10 percent of the actual quantity required for that half station.
b.Embankment . If provided in the Contract, embankment material will be measured in its final compacted position in the roadway. Measurement will be made upward from the original ground line without any allowance for subsidence due to compaction of the base under the embankment. The original cross -sections will be used for determination of volumes of embankment material placed, unless changes have been directed. The measured volume of embankment material will be increased by the volume of topsoil or wetland topsoil removed from the area below the original ground line and under the embankment.
c.Rock Fill. Rock fill will be measured as the volume in cubic yards in its final position, unless otherwise specified, and shall be limited to the elevations specified.
d.Blading and Dozing . The quantity measured for blading and dozing will be the number of hours that each motor grader or bulldozer is actually used as ordered. A minimum of four hours for any half shift or part thereof will be paid for unless the equipment is inoperative due to breakdown or other causes determined to be the Contractor’s responsibility. Time involved in moving onto or off the project will not be measured and paid for. Time will be paid for moving motor graders or bulldozers from one location on the project to another, if directed; but time will not be allowed for moves that are made for the convenience of the Contractor. Payment for a minimum of four hours will not be allowed in cases where the motor grader, bulldozer, or operator is assigned to work on other pay items connected with the project. 203-12 (e) Potholing . Potholing will be measured by the total number of hours that excavation and backfilling equipment is actually used as directed. All other related work, including removal of existing pavement, backfilling, shoring, and labor will not be measured and paid for separately, but shall be included in the work.
f.Proof Rolling . Proof rolling will be measured by the actual number of hours that the pneumatic equipment is used as a proof roller. The time to be measured under this item will be the number of hours that each piece of equipment is actually used as ordered. Proof rolling will be measured and paid for only once for each test strip required during construction; for final verification of subgrade before placement of subbase, base coarse, or pavement; or for each incident where the Engineer directs it through the course of construction. Additional proof rolling that is required due to failure of embankment fill; due to the Co ntractor’s failure to place subbase, base course, or initial pavement course within 48 hours of the initial proof roll; or due to the condition of the subgrade changing due to weather; or additional proof rolls deemed necessary due to the Contractor’s choice to deviate from minimum equipment and compaction efforts specified, shall be at the Contractor’s expense. BASIS OF PAYMENT
203.12 The accepted quantities will be paid for at the contract unit price for each of the
pay items listed below that appear in the bid schedule. Payment will be made under: Pay Item Unit Rock Excavation Cubic Yard Rock Fill Cubic Yard Unclassified Excavation Cubic Yard Unclassified Excavation (Complete in Place) Cubic Yard Unsuitable Materials Cubic Yard Borrow Cubic Yard Borrow (Complete in Place) Cubic Yard Embankment Material (Complete in Place) Cubic Yard Stripping Cubic Yard Blading Hour Dozing Hour Potholing Hour Proof Rolling Hour Water will not be measured and paid for separately but shall be included in the work. Compaction will not be measured and paid for separately but shall be included in the work. 203-13 Payment for replacement of unsuitable material shall be as follows: If excavated material can be re -used as embankment fill by moisture conditioning and compaction, replacement shall be included in the cost for Unsuitable Material. If the material cannot be re -used as embankment fill, payment for replacement of unsuitable material shall be for the volume that is placed in the excavated area at the respective unit price for the material that is approved by the Engineer and used. Payment for Unclassified Excavation (Complete in Place), Embankment Material (Complete in Place), or Borrow (Complete in Place) shall be full compensation for all work necessary to complete the item including construction of embankments, reworking of exist ing materials to satisfy benching requirements, unclassified excavation, borrow, compaction, compaction of bases of cuts and fills, all work in available materials pits, and disposal of excess excavated material. Reducing the size of the claystone particles, removing the oversized particles, and disposal of the oversized particles will not be measured and paid for separately but shall be included in the work. Ripping tests or seismic tests used to evaluate whether a material meets the criteria for Rock Excavation will not be measured and paid for separately but shall be included in the work. Pavement replacement if required due to potholing, shall be accomplished, measured, and paid for per appropriate sections of the specifications. Pneumatic tire equipment and load required to achieve the desired weight of proof rolling equipment will not be measured and paid for separately but shall be included in the work. 203-14 THIS PAGE INTENTIONALLY LEFT BLANK 206.01 206-1 SECTION 206 EXCAVATION AND BACKFILL FOR STRUCTURES DESCRIPTION
206.01 This work consists of the excavation and backfill, or disposal of all material required
for the construction of structures. The excavation and disposal of excavated material for ditches and channels shall be accomplished per Section 203. All excavation and backfill for structures below the designed slope or subgrade line provided in the Contract shall be included under this item. Unless otherwise specified, structure excavation shall include all pumping, bailing, draining, and incidentals required for proper execution of the work. MATERIALS
206.02 General. All structure backfill, bed course material, and filter material will be accepted
in place.
a.Structure Backfill.
1.Structure Backfill (Class 1), (Class 2), and (Class 3). Class 1, Class 2, and Class 3 structure backfill shall be composed of non -organic mineral aggregates and soil from excavations, borrow pits, or other sources. Material shall conform to the requiremen ts of subsection 703. 08. Class of material shall be as specified in the Contract or as designated. Structure Backfill (Class 1) with mechanical reinforcement shall be used to backfill bridge abutments, unless otherwise shown on the Plans. Imported material used as structure backfill for pipes (storm sewer , cross culverts, side drains, etc.) shall meet the requirements of the Class specified and the requirements of subsection 206.02(a)3. The Contractor may substitute Structure Backfill (Flow -Fill) conforming to subsection 206.02(a)2 for Structure Backfill (Class 1) or Structure Backfill (Class 2) to backfill culverts and sewer pipes. The Contractor may also substitute Structure Backfill (Class 3) as backfill for culverts and sewer pipes.
2.Structure Backfill (Flow -Fill). Flow -Fill shall be a self -leveling low strength concrete material composed of cement, fly ash, aggregates, water, chemical admixtures or cellular foam for air -entrainment. Flow -fill shall have a slump of 7 to 10 inches, when tested per ASTM C143 or a minimum flow consistency of 6 inches when tested per ASTM D6103. Flow- Fill shall have a minimum compressive strength of 50 psi at 28 days when tested per ASTM D4832. Flash fill is a rapid setting Flow -Fill that may be used when approved by the Engineer and will be tested, accepted, and paid for as Flow -Fill.
Source: Colorado Standard Specifications for Road and Bridge Construction, 2023 Edition. Pages 203–216 of 943.