Article 1 — Description
Mix and compact cement, water, and subgrade or base (with or without asphalt concrete pavement) in the roadway.
Article 2 — Materials
Furnish uncontaminated materials of uniform quality that meet the requirements of the plans and specifications. Notify the Engineer of the proposed material sources and of changes to material sources. Obtain verification from the Engineer that the specification requirements are met before using the sources. The Engineer may sample and test project materials at any time before compaction. Use material definitions in accordance with Tex -100-E .
2.1 Cement . Furnish hydraulic cement that meets the requirements of DMS -4600 , “Hydraulic Cement,” and the
Department’s Hydraulic Cement Quality Monitoring Program (HCQMP). Sources not i n the HCQMP will require testing and approval before use.
2.2 Subgrade . The Engineer will determine the sulfate content in accordance with Tex -145-E and organic
content in accordance with Tex-148-E before cement treatment begins. Suspend operations when material to be treated has a sulfate content greater than 7, 000 ppm or an organic content greater than 2 .0% and proceed as directed.
2.3 Flexible Base. Unless otherwise shown on the plans, furnish base material that meets the requirements of
Item 247, “Flexible Base,” for the type and grade shown on the plans, before the addition of cement. Unless otherwise shown on the plans, the compressive strength of the flexible base is waived.
2.4 Water . Furnish water free of industrial waste and other objectionable material.
2.5 Asphalt . When asphalt or emulsion is permitted for curing purposes, furnish materials that meet the
requirements of Item 300, “Asphalts, Oils, and Emulsions,” as shown on the plans or directed.
2.6 Mix Design . The Engineer will determine the target cement content and optimum moisture content to
produce a stabilized mixture that meets the strength requirements shown on the plans. The mix will be designed in accordance with Tex -120-E or will be based on prior experience with the project materials. The Contractor may propose a mix design developed in accordance with Tex-120-E . Meet strength requirements when shown on the plans. The Engineer will use Tex-120-E to verify the Contractor’s proposed mix design before acceptance. Reimburse the Department for subsequent mix designs or partial designs necessitated by changes in the material or requests by the Contractor. Limit the amount of recycled asphalt pavement to no more than 50% of the mix unless otherwise shown on the plans or directed.
Article 3 — Equipment
Provide machinery, tools, and equipment necessary for proper execution of the work . Provide rollers in accordance with Item 210, “Rolling.” Provide proof rollers in accordance with Item 216, “Proof Rolling,” when required.
3.1 Cement Storage Facility. Store cement in closed, weatherproof containers.
184 3.2. Cement Slurry Equipment . Use slurry tanks equipped with agitation devices to slurry cement on the project or other approved location. The Engineer may approve other slurrying methods. Provide a pump for agitating the slurry when the distributor truck is not equipped with an agitator. Equip the distributor truck with an approved sampling device.
3.3 Dry Cement Distribution Equipment . Provide equipment to spread cement evenly across the area to be
treated. Provide equipment with a rotary vane feeder to spread cement, when shown on the plans .
3.4 Pulverization Equipment . Provide pulverization equipment that:
cuts and pulverizes material uniformly to the proper depth using cutters that plane to a uniform surface over the entire width of the cut, provides a visible indication of the depth of cut at all times, and uniformly mixes the materials.
Article 4 — Construction
Construct each layer uniformly, free of loose or segregated areas , and with the required density and moisture content. Provide a smooth surface that conforms to the typical sections, lines, and grades shown on the plans or as directed.
4.1 Preparation of Subgrade or Existing Base for Treatment . Before treating, remove existing asphalt
concrete pavement in conformance with pertinent Items and the plans or as directed. Shape existing material in conformance with applicable bid items to conform to the typical sections shown on the plans and as directed. When shown on the plans or directed, proof roll the roadbed in accordance with Item 216 before pulverizing or scarifying existing material. Correct soft spots as directed. When material is imported from a borrow source, notify the Engineer of the location of the borrow source well in advance to allow time for testing and approval to avoid delay to the project. Stockpile as directed. The Engineer will test the borrow source and determine the sulfate and organic contents. When the borrow source has a sulfate content greater than 3, 000 ppm or an organic content greater than 2 .0%, proceed as directed. When new base material is required to be mixed with existing base, deliver, place, and spread the new material in the required amount per station. Manipulate and thoroughly mix new base with existing material to provide a uniform mixture to the specified depth before shaping.
4.2 Pulverization . Pulverize or scarify existing material after shaping. If the material cannot be uniformly
processed to the required depth in a single pass, excavate and windrow the material to expose a secondary grade to achieve processing to plan depth.
4.3 Application of Cement . Uniformly apply cement using dry placement unless otherwise shown on the plans.
Add cement at the percentage determined in accordance with Section 275.2.6., “Mix Design.” Apply cement only on an area where mixing, compacting, and finishing can be completed during the same working day. Start c ement application only when the air temperature is at least 35°F and rising or is at least 40°F. The temperature will be taken in the shade and away from artificial heat. Suspend application when the Engineer determines that weather conditions are unsuitable.
4.3.1 Dry Placement . Before applying cement, bring the prepared roadway to approximately optimum moisture
content. When necessary, sprinkle in accordance with Item 204, “Sprinkling.” Distribute the required quantity of dry cement using approved equipment. Minimize dust and scattering of cement by wind. Do not apply 185 cement when wind conditions, in the opinion of the Engineer, cause blowing cement to become dangerous to traffic or objectionable to adjacent property owners.
4.3.2 Slurry Placement . Mix the required quantity of cement with water, as approved. Provide slurry free of
objectionable materials and with a uniform consistency that can be easily applied. Agitate the slurry continuously. Apply slurry within 2 h r. of adding water and when the roadway is at a moisture content drier than optimum. Distribute slurry uniformly by making successive passes over a measured section of roadway until the specified cement content is reached.
4.4 Mixing . Thoroughly mix the material and cement using approved equipment. Mix until a homogeneous
mixture is obtained. Sprinkle the treated materials during the mixing operation, as directed, to maintain optimum mixing moisture. Spread and shape the completed mixture in a uniform layer. After mixing, the Engineer may sample the mixture at roadway moisture and test in accordance with Tex-101-E , Part III, to determine compliance with the gradation requirements shown in Table 1. When strength requirements are shown on the plans, the Engineer may sample the mixture to verify strength in accordance with Tex-120-E and adjust cement content to achieve the target strength for work going forward. Table 1 Gradation Requirements (Min % Passing ) Sieve Size Base Subgrade 1-3/4″ 100 100 3/4″ 85 85 #4 – 60
4.5 Strength Testing. The Engineer will sample and test the cement -treated mixture for unconfined compressive
strength in accordance with Tex -117-E , Part II. The unconfined compressive strength must be greater than 150 psi, unless otherwise shown on the plans.
4.6 Compaction. Compact the mixture in one lift using density control , unless otherwise shown on the plans.
Com plete compaction within 2 hr. after the application of water to the mixture of material and cement . Sprinkle the treated material in accordance with Item 204, or aerate the treated material to adjust the moisture content during compaction so that it is within 2.0% of optimum as determined in accordance with Tex-120-E . Adjust operations as required. Begin rolling longitudinally at the sides and proceed toward the center, overlapping on successive trips by at least one- half the width of the roller unit. On superelevated curves, begin rolling at the low side and progress toward the high side. Offset alternat ing trips of the roller. Operate rollers at a speed between 2 and 6 mph, as directed. Before final acceptance, the Engineer will select the locations of tests in each unit and measure the treated depth in accordance with Tex -140-E . Correct areas deficient by more than 1/2 in. in thickness or more than 1/2% in target cement content by adding cement as required, reshaping, recompacting, and refinishing at the Contractor’s expense. Remove or rework areas that lose required stability, compaction, or finish, as directed. When a section is reworked more than 4 hr. after completion of compaction, add additional cement as directed. Perform the work at no additional cost to the Department .
4.6.1 Ordinary Compaction. Roll using approved compaction equipment, as directed. Correct irregularities, depressions, and weak spots immediately by scarifying the areas affected, adding or removing treated material as required, reshaping, and recompacting.
4.6.2 Density and Moisture Control . Compact to at least 95% of the maximum density and within ±2.0% of the
optimum moisture content as determined in accordance with Tex-120-E . Provide the Engineer with the beginning and ending station numbers of the area completed for testing. The Engineer will determine 186 roadway density and moisture content in accordance with Tex -115-E, Part I within 4 hr. from the time compaction is c ompleted. The Engineer will determine random locations for testing in accordance with Tex-115-E , Part IV. The Engineer may verify strength in accordance with Tex -120-E and adjust cement content to achieve the target strength for work going forward. Remove material that does not meet density requirements , or rework by adding the target cement content, reshaping, recompacting, and refinishing, at the Contractor’s expense. When the density is less than 95% of the maximum dry density, the Engineer may perform additional testing to determine the extent of the area to correct . The Engineer may accept the section if no more than one of the five most recent density tests is below the specified density and the failing test is no more than 3 pcf below the specified density.
4.7 Miscellaneous and Small Areas . Miscellaneous areas are those that typically involve handwork or
discontinuous paving operations, such as temporary detours, driveways, mailbox turnouts, crossovers, gores, spot level -up areas, and other similar areas. Miscellaneous and small areas are not subject to density testing but may be tested as directed.
4.8 Finishing. Immediately after completing compaction of the final course, clip, skin, or tight -blade the surface
of the cement treated material using a maintainer or subgrade trimmer to a depth of approximately 1/4 in. Remove loosened material and dispose of at an approved location. Roll the clipped surface immediately using a pneumatic tire roller until a smooth surface is attained. Add small amount s of water as needed during rolling. Shape and maintain the course and surface in conformity with the typical sections, lines , and grades shown on the plans or as directed. Finish grade of constructed subgrade to within 0.1 ft. in the cross -section and 0.1 ft. in 16 ft. measured longitudinally . Correct grade deviations of constructed base greater than 1/4 in. in 16 ft. measured longitudinally or greater than 1/4 in. over the entire width of the cross -section in areas where surfacing is to be placed. Remove excess material, reshape, and roll using a pneumatic tire roller. Correct as directed if material is more than 1/4 in. low. D o not surface patch.
4.9 Microcracking . When shown on the plans, maintain moisture content of the finished cement -treated base for
a period of 24–48 hr. During this time, but no sooner than 24 hr., roll the finished course using a vibratory roller to induce microcracking. The vibratory roller must be in accordance with Item 210, with a static weight equal to or more than 12 ton, and the vibratory drum must be no less than 20 in. wide. The roller must travel at a speed of 2 mph, vibrating at maximum amplitude, and make two –four passes with 100% coverage excluding the outside 1 ft. of the surface crown, unless otherwise directed by the Engineer. Additional passes may be required to achieve the desired crack pattern as directed. Notify the Engineer 24 h r. before the microcracking begins .
4.10 Curing. Cure for at least 3 days by sprinkling in accordance with Item 204 or by applying an asphalt material at the rate of 0.05–0.20 gal. per square yard, as shown on the plans or as directed. When a section is
microcracked, cure section for an additional 2 days after microcracking. Maintain the moisture content dur ing curing at no lower than 2 percentage points below optimum. Continue curing until placing another course.
4.11 Ride Quality. When sho wn on the plans, measurement of ride quality only applies to the final travel lanes
that receive a one- or two-course surface treatment for the final riding surface. Measure the ride quality of the base course either before or after the application of the prime coat, as directed, and before placement of the surface treatment. Use a certified profiler operator on the Department ’s MPL. When requested, furnish the Engineer with documentation for the person certified to operate the profiler. Provide all profile data to the Engineer in electronic data files within 3 days of measuring the ride quality using the format specified in Tex-1001-S . The Engineer will use Department software to evaluate longitudinal profiles to determine areas requiring corrective action. Correct 0.1- mi. sections with an average international roughness index (IRI) value greater than 100 in. per mile to an IRI value of 100 in. per mile or less, unless otherwise shown on the plans. Reprofile and correct sections that fail to maintain ride quality before the 187 placement of the surface treatment , as directed and approved. Unless ride deterioration is due to environmental impact, traffic, or other incidents outside the C ontractor’s control, perform this work at no additional expense to the Department, as approved.
Article 5 — Measurement
5.1 Cement . Cement will be measured by the ton (dry weight). When cement is furnished in trucks, the weight of
cement will be determined on certified scales, or the Contractor must provide a set of standard platform truck scales at a n approved location. Scales must meet the requirements of Item 520, “Weighing and Measuring Equipment.” When cement is furnished in bags, indicate the manufacturer’s certified weight. Bags varying more than 5% from that weight may be rejected. The average weight of bags in any shipment, as determined by weighing 10 bags taken at random, must be at least the manufacturer’s certified weight.
5.1.1 Slurry . Cement slurry will be measured by the ton (dry weight) of the cement used to prepare the slurry at
the jobsite or from the minimum percent dry solids content of the slurry, multiplied by the weight of the slurry in tons delivered.
5.2 Cement Treatment . Cement treatment will be measured by the square yard of surface area. The dimensions
for determining the surface areas are established by the widths shown on the plans and lengths measured at placement.
Article 6 — Payment
The work performed and materials furnished in accordance with this Item and measured as provided under “Measurement” will be paid for in accordance with Section 275.5.1., “Cement,” and Section 275.5.2., “Cement Treatment.” Furnishing and delivering new base will be paid for in accordance with Section 247.6.2., “Flexible Base (Roadway Delivery).” Mixing, spreading, blading, shaping, compacting, and finishing new or existing base material will be paid for under Section 275.6.2., “Cement Treatment.” Removal and disposal of existing asphalt concrete pavement will be paid for in conformance with pertinent Items or in accordance with Article 4.4., “Changes in the Work.” Sprinkling and rolling, except proof rolling, will not be paid for directly , but will be subsidiary to this Item, unless otherwise shown on the plans. When proof rolling is shown on the plans or directed by the Engineer, it will be paid for in accordance with Item 216. Where subgrade is constructed under this Contract, correction of soft spots in the subgrade or existing base will be at the Contractor’s expense. Where subgrade is not constructed under this Contract, correction of soft spots in the subgrade or existing base will be in conformance with pertinent Items or in accordance with Article 4.4., “Changes in the Work.” Where subgrade to be treated under this Contract has sulfates greater than 7,000 ppm, work will be paid for in accordance with Article 4.4., “Changes in the Work.” Asphalt used solely for curing will not be paid for directly, but will be subsidiary to this Item. Asphalt placed for curing and priming will be paid for under Item 310, “Prime Coat.”
6.1 Cement . Cement will be paid for at the unit price bid for “Cement.” This price is full compensation for
materials, delivery, equipment, labor, tools, and incidentals.
6.2 Cement Treatment . Cement treatment will be paid for at the unit price bid for “Cement Treatment (Existing
Material),” “Cement Treatment (New Base),” or “Cement Treatment (Mixing Existing Material and New Base),” for the depth specified. No payment will be made for thickness or width exceeding that shown on the 188 plans. This price is full compensation for shaping existing material, loosening, mixing, pulverizing, spreading, applying cement, compacting, microcracking, finishing, curing, curing materials, blading, shaping and maintaining shape, replacing mixture, disposing of loosened materials, processing, hauling, preparing secondary subgrade, water, equipment, labor, tools, and incidentals.