453.01 Description.
PRESSURE GROUTING AND REPAIR OF PORTLAND CEMENT CONCRETE PAVEMENT
453.01 Description.
The work covered by this Secti on consists of the stabilization of existing unstable concrete pavement slabs by pressure pumping of a specified grout under the slabs along with the removal and replacement of designated shattered paving slabs or sections of slabs. The word slab in this S ection shall mean not only a slab, or a portion of a slab, in a jointed concrete pavement system, but also a portion of a continuously reinforced concrete pavement. Pressure pumping of grout or subsealing of the pavement slabs is intended to stabilize the slab by filling voids and cavities under the slabs with a grout mixture that will form a hard insoluble mass. Removal and replacement of concrete pavement shall be as directed by the Engineer. Cracking in concrete pavement is defined as follows: Hairline cracks - Small, tight cracks which in width resemble shrinkage cracks. No corrective repair procedure is required. Low severity cracks - Wider than hairline cracks with the crack opening clearly visible. The concrete on both sides of the crack is acting with interlock between the cracked pieces limiting movement of the individual pieces. Medium severity cracks - The concrete on both sides of the crack is acting with partial interlock between the cracked pieces allowing potential or actual small mov ement of the individual pieces. High severity cracks - The concrete on both sides of the crack is acting independently allowing unrestricted movement of the individual pieces. If the crack does not have the same severity level along the entire length, the crack will be rated as the highest severity level present. Appropriate repair procedures for the various types of cracked slabs in a jointed pavement are as follows: Low severity cracking will not require the removal of pavement. These cracks will be routed and sealed under Item 454 -A. Medium severity cracking will require the removal and replacement of at least a portion of the concrete slab. The entire slab is to be removed and replaced if broken into four or more pieces by at least medium severity cracks . High severity cracking will require the removal and replacement of at least a portion of the concrete slab. The entire slab is to be removed and replaced if it is broken into three or more pieces of high severity cracks. Due to the variations in quantiti es that can be experienced in this type work, the quantities for the items in this Section cannot be accurately determined before the work is done; therefore, the items in this Section shall be excluded from those items which may have their unit price adju sted as allowed by Subarticle 104.02(a). At any time during the life of the project, should any process or work herein be deemed ineffective or unnecessary by the Engineer, the Engineer may order any and/or all work under this Section stopped, reduced, and/or eliminated. In such case, the Contractor will be paid for all work ordered and performed. No claim will be considered because of elimination or reduction of work under this Section.
453.02 Materials.
a.General . Materials furnished for use shall confo rm to the appropriate requirements of Division 800, Materials, and the requirements noted in this Article.
b.Grout . The grout used in pressure grouting shall consist of one of the mixtures shown in Table I with the materials complying with the following: Type I or III Cement - Articles 815.01 and 815.03 Calcium Chloride - Section 805 Type I Fly Ash - Section 806 modified to waive the Loss on Ignition requirement
453.03 Construction Requirements.
Water - Section 807 Admixtures - Section 808 and 809 Limestone Dust - Limestone dust shall be t horoughly dry, free of lumps, meeting the following gradation requirements: Size % Passing by Weight {Mass} No. 30 {600 µm} Sieve 100 No. 100 {150 µm} Sieve 90 - 100 No. 200 {75 µm} Sieve 65 - 100 Fine Sand Fine sand shall comply with the appropriate requirements of Section 802 allowing the use of manufactured sand from limestone, sandstone or granite, or natural silica fine sand meeting the following gradation requirements: Size % Passing by Weight {Mass} No. 10 {2.00 mm} Sieve 95 - 100 No. 60 {250 µm} Sieve 40 - 90 No. 200 {75 µm} Sieve 0 - 50 Percent Silt 0 - 25 Percent Clay 0 - 12 Percent Organic Material 0 - 3 Sand shall be non -plastic as determined by AASHTO T 89 and T 90.
c.Concrete . Concrete for Portland Cement concrete pavement replacement shall meet the requirements of Section 450 utilizing either Type III cement or Type I cement containing a non -chloride accelerator. The use of an accelerator will not be required when the ambient air temperature is above 85 °F {29 °C}.
d.Adhesives . Adhesives furnished for anchoring tie bars and dowel bars shall meet the requirements of Article 870.04.
453.03 Construction Requirements.
a.Equipment .
1.Equipment for Pressure Grouting . The equipment for pressure grouting of concrete pavement shall be that customarily used in the pressure grouting of earthen embankments or in mud- jacking of concrete pavement consisting of at least the following:
a.Air compressors of sufficient capacity for operating pneumatic hammers.
b.A discharge pipe with an adequate securing device.
c.Pneumatic hammers equipped with drills that will cut 1.5 inch {38 mm} diameter or other approved diameter holes through the rigid pavement. The equipment shall be operated in such a manner so as to prevent unnecessary damage to the slab.
d.A portable gage apparatus which operates from the shoulder and is capable of monitoring slab movement during grouting of holes near the pavement edge. Dial gages with at least 1 inch {25 mm} of travel arm and capable of detecting 0.001 of an inch {25 µm} of movement shall be placed within 1 foot {300 mm} of the hole being grouted and 1 foot {300 mm} outside the edge of paving. The dial gage measuring movement with in 1 foot {300 mm} of the hole being grouted shall have an arm length of at least 6 feet {1.8 m}. The base of the support for the gage apparatus shall be a minimum of 5 feet {1.5 m} outside the edge of paving during the monitoring of movement and shall be moved along the shoulder during the grouting of holes along the
453.03 Construction Requirements.
pavement edge. An engineer's level, furnished and operated by the Department, will be used, periodically throughout the day, to supplement the gage apparatus to monitor slab movement. Alterna te gage apparatus setups may be used if requested in writing by the Contractor and approved by the Engineer.
e.Blow pipe to enlarge void area.
f.Equipment for accurately measuring and proportioning by volume or weight {mass} the various materials composi ng the grout. When volume is used, the weight per cubic foot {mass per cubic meter} of the materials will be determined and mix proportions adjusted accordingly.
g.A batch type mixer, capable of thoroughly mixing the various components of the grout. A hig h speed, colloidal type mixer will be required for grout mixes containing only cement and fly ash.
h.A positive action pump capable of forcing grout through a drilled hole into voids and cavities beneath the pavement slab. The pump shall be capable of sup plying adequate pressure at the end of the discharge pipe to insure filling of all voids at the required hole spacing. A gage shall be located on the discharge side of the pump to measure the pumping pressure.
i.A flow cone with all necessary components s o that the Engineer may make an accurate field determination of the consistency of the grout. The flow cone shall conform to the dimensions and other requirements of ALDOT -338.
2.Equipment for Removal and Replacement. The equipment for removal and repla cement of the concrete pavement slabs shall be suitable for the purpose intended and approved by the Engineer. Attention is directed to the operational requirements for removal and replacement in Subarticle (c) below.
b.Pressure Grouting of Pavement Slab s.
1.Weather Limitations . Unless approved otherwise by the Engineer in writing, all pressure grouting shall be performed between the dates of April 1 and November 1. Pressure grouting operations may not be started unless the air temperature, in the shade and away from artificial heat, is at least 35 °F {2 °C} and rising. Pressure grouting shall stop if the temperature is 40 °F {4 °C} and falling or when the subgrade contains an abnormal amount of moisture as evidenced by standing water on the pavemen t or in joints or cracks. To accelerate setting and provide early strength to mixes utilizing Type I cement, calcium chloride shall be used in the proportions tabulated below for respective temperature ranges. Normal traffic flow may be resumed three hours after grouting. Atmospheric Temperature % Calcium Chloride by Weight {Mass} Of Type I Cement 35 – 55 °F {2 - 12 °C} 5 56 – 69 °F {13 - 20 °C} 4 70 – 79 °F {21 - 26 °C} 3 80 – 89 °F {27 - 31 °C} 2 90 °F {32 °C} and above 1 When Type III cement is used, 0 -2% calcium chloride may be required as needed to accelerate setting in cold weather. Grouted slabs may be opened to traffic in accordance with Subarticle 453.03(d).
2.Preparation of Grout Mixture . The mixtures used in pressure grouting s hall consist of the proportions tabulated in Table I. The consistency may be varied by the addition of water and/or other additives. The quantity by weight {mass} of equivalent 100% pure calcium chloride to be included in the mixture shall be in accordance with Item 1 above. The calcium chloride, when required, shall be thoroughly pre -mixed in the approximate quantity of mixing water required for a predetermined batch size before combining with the other ingredients. The consistency of the grout shall be de termined in accordance with ALDOT -338. The quantity of mixing water used shall be that which will produce a grout of such consistency that the time of efflux from the flow cone will be a minimum of 14 seconds and a maximum of 22 seconds for undersealing. A fter the initial introduction of a sufficient amount of water into the mixture to obtain the necessary consistency, no additional water shall be added. The grout shall be used within 90 minutes after introduction of water into the mixture.
453.03 Construction Requirements.
Dry ingredients may be added to a mixed batch only in the amounts necessary to bring a too thin mixture to the required consistency. In this case the added dry ingredients shall be in the specified ratio. Grout which fails to meet the flow requirements specified above sh all not be used in grouting operations. A grout mixture shall be selected by the Contractor from the mixtures shown in Table I below. The Engineer reserves the right to specify a different mixture if the one chosen by the Contractor fails to produce the desired results. TABLE I GROUT MIXTURES Mix Proportions, Percent by Volume of Dry Ingredients Grout Type 1 2 3 4 5 6 Fine Sand 30 50 50 Limestone Dust 50 80 30 Fly Ash 80 30 50 30 Cement 20 20 20 20 20 20
3.Construction. Selected slabs designated by the Department for pressure grouting shall be drilled as indicated on the plans or designated by the Engineer. For holes nearest the edges of the slab, the joints, or a major crack, a maximum of 3 inches {75 mm} from the precise marked location is considered to be reasonable. For other holes, a maximum 6 inch {150 mm} tolerance is considered to be reasonable. Should it become necessary or desirable to drill holes at locations other than those shown on the plans, such holes shall be drill ed only as approved by the Engineer. In no instance shall holes be drilled in the wheel paths of a lane. The drills shall be rotated to avoid cracking the pavement and to provide satisfactory holes of the proper diameter for effective operations in pressure grouting. When drilling holes, the drills shall be held as nearly perpendicular to the pavement surface as possible. Holes which cannot be satisfactorily used in pressure grouting shall be filled with grout and not measured for pay; new holes shall be dr illed. After the holes are drilled, and just prior to pressure grouting, a high pressure air pipe may be required to clean the hole, if deemed necessary by the Engineer, to facilitate introduction of the grout. After the holes are cleaned, the discharge ho se on the pressure grout pump shall be connected to the hole in a manner that will provide adequate seal to maintain pressure past the connection. The discharge end of the pipe shall not extend below the lower surface of the concrete pavement. To fill all voids, pumping of grout will be required in holes designated by the Engineer. The maximum pressure allowed during the grouting operation will be 200 psi {1.5 Mpa}. A gage shall be located on the discharge side of the pump to measure the pumping pressure. N ormally, indication that grout is flowing out of an adjacent hole or joint or the edge of the slab is sufficient evidence that all cavities or voids are filled within the range of the hole being grouted and pumping in such hole shall cease. Additional evid ence that grouting should cease is a rapid rise of the slab, or indications of a rise of the adjacent shoulder. A minimal lifting of the slab will be allowed but not to exceed 0.05 of an inch {1 mm} per grouting pass. Care shall be taken not to crack slabs by differential lifting. Any slab or portion of slab or shoulder which is raised more than 0.05 of an inch {1 mm} each grouting will require corrective action, without payment, by the Contractor. Such corrective action shall consist of grinding or other m ethods approved by the Engineer. After grouting has been completed in a drill hole, the discharge pipe shall be withdrawn and latent grout removed. The hole shall not be plugged unless authorized otherwise by the Construction Engineer. Patching of the hole shall begin after the grout has taken an initial set. The grout shall be removed to a minimum depth of 4 inches {100 mm} below the pavement surface. A low slump concrete mix consisting of 1 -part Type I or Type III cement and 2 -parts No. 100 concrete sand by volume shall then be placed in the hole, rodded and leveled with the pavement surface. Filled holes that later shrink below the finished surface, ravel out, or otherwise become damaged before project completion shall be repaired. Corrective measures sha ll be taken in case stooling occurs by making proper adjustment in the stiffness of the grout being used. In case stooling does occur, additional holes shall be provided as
453.03 Construction Requirements.
directed and a more fluid grout shall be pumped through these new holes to fill the voids between the stools. At least 24 hours, but no later than 5 days, after a slab has been grouted, it shall be tested for movement between the hours of 3:00 a.m. and 7:00 a.m. On cool, cloudy days, this time frame may be extended if approved by the Eng ineer. The test rolling equipment shall be rubber -tired and of sufficient weight {mass} to give a 20,000 pounds {90 kN} single axle load with a minimum of 10,000 pounds {45 kN} per side (a properly loaded dump truck may be used). Each slab shall be tested by making one or more passes over it with the test roller. The rolling shall be slow enough to allow an observer to measure the movement and mark the slab if regrouting is needed. If the slab moves 0.03 of an inch {0.8 mm} or more during the test rolling, new holes shall be drilled and the slab regrouted. All slabs which have been regrouted shall be retested as outlined above for the initial testing. After two returns for regrouting, should the slab fail the test rolling, the Engineer will make the decision to leave the slab as is, continue regrouting, or remove and replace the slab. Payment will be made under the appropriate pay items for the additional drill holes and grout used in the regrouting operation. The cost of test rolling shall be absorbed in oth er items of work. The construction methods outlined above may be modified by the Engineer as field conditions indicate. Pressure grouting operations shall cease at least three hours before sundown, except that on cloudy days pressure grouting operations sh all cease earlier as necessary to permit grout to harden at least three hours prior to allowing traffic back on the grouted slab before first darkness. First darkness shall be defined as that time of day the average traveling public vehicle would first beg in to use its headlights.
c.Removal and Replacement of Pavement Slabs .
1.Removal . The extent of removal shall be as shown on the plans or directed by the Engineer. The slab section designated for removal shall be sawed as shown on the plans. The Contractor shall not oversaw the slab within 2 feet {600 mm} of another oversaw or within 2 feet {600 mm} of any type of joint. Transverse cuts for removal and the placing of new steel tie bars shall be performed as shown by plan details. The sections of pavement to be removed may be removed in any manner approved by the Engineer which does not damage the underlying base layer, adjacent concrete slabs, or the joint steel. Any damage to the underlying base or adjacent slabs shall be repaired to the satisfact ion of the Engineer. Joint steel shall be cleaned and reconditioned to provide the same load transfer and/or tie as in the original pavement design. Any damaged or destroyed steel, which in the opinion of the Engineer would not function properly, shall be replaced in kind and retied to the old pavement by drilling an appropriate size hole of the proper depth and anchoring the new bar with an approved adhesive material. This replacement also includes steel damaged or destroyed previous to the removal operati on. All tie bars and dowel bars tied to the old pavement shall be anchored into place with an approved adhesive material in such a manner as to meet a 7200 pound {32 kN}, minimum, pull -out requirement. The Department will perform the pull -out tests in accordance with ALDOT -366. The Contractor shall supply the equipment necessary to perform the pull -out test. Slabs shall be removed and replaced during the same day. Preparation for removal, including sawing the slab into smaller pieces, may be done the day prior to removal, but traffic shall be maintained on the slab the night before removal.
2.Concrete Pavement Replacement . After completion of removal operation, the joint steel and/or reinforcing steel shall be reconditioned or replaced (reconditioned means the cleaning and straightening of the steel bars and the cleaning, painting, greasing, replacement, etc. of the dowels), new tie bars placed as detailed by the plans, and the base cleaned and repaired as directed, and then the slab shall be poured. The Contractor shall provide gang drills or templates that will provide the proper alignment for holes drilled for dowels or tie bars. The size of the drilled hole shall be 1/8 of an inch {3 mm} greater in diameter than the diameter of the dowel or tie bar being installed therein. The drill used shall not cause any spalling of the existing concrete around the face of the drill hole. The Contractor shall provide a device that will place the adhesive in the back of the drilled hole first and then proceed toward the front. After the dowels or tie bars are anchored in place, the Contractor shall allow time for the adhesive to set and then allow sufficient time for any required pull-out tests to be per formed prior to pouring the replacement slab.
453.05 Basis of Payment.
The concrete paving sla b shall be poured in accordance with the provisions of Section 450 except that Structural Portland Cement Concrete meeting the requirements of Section 501 for a Class A concrete utilizing either Type III cement or Type I cement with a non -chloride accelera tor, shall be used and a full paving train will not be required. Unless shown otherwise by the plans, the surface finish and slope of the new pavement shall be the same as the adjoining pavement slabs. If the pavement is to be covered by a bituminous overl ay, a wood float finish and straight slope will be acceptable. All joints, except expansion joints, with adjacent pavement shall be butt type tied construction joints. Expansion joints shall be reconstructed so that the continuity of existing expansion joints are retained utilizing similar joint filler and sealed with the type sealer specified on the plans. Other reconstructed joints which require sealing shall be sealed with the specified type sealer. When a joint is completely removed, new materials shal l be used throughout the joint. All materials necessary to repair or reconstruct the joints in or adjacent to the concrete pavement replacement is considered incidental to said replacement. All joints shall be constructed in accordance with the provisions of Subarticle 450.03(j) except as noted herein. Due to the requirement for the use of either an accelerator or Type III cement in the concrete mix, extreme care shall be taken to see that joints are saw cut before uncontrolled shrinkage cracking begins. Slabs that have been removed shall be replaced the same day they are removed. The Contractor shall use such approved methods as necessary to keep all pavement surfaces adjacent to this operation reasonably clean of excess grout or other materials at all tim es.
d.Opening to Traffic . No traffic, including construction equipment, will be permitted on the grouted slabs until at least three hours after the grouting has been completed. No traffic, including construction equipment will be permitted on the replace d slab until at least six hours after the slab has been poured. Traffic shall be placed on grouted slabs before first darkness of the same day that the slabs were grouted; traffic shall be placed on replaced slabs no later than the morning following the da y the slabs were replaced.
453.04 Method of Measurement.
Each drill hole through the concrete paving slab ordered by the Engineer and placed in accordance with the requirements noted herein in this Section and properly filled after satisfactory use will be measured for payment. Portland cement concrete grout will be measured for payment by the bag (94 pounds {42 kg}) of Portland cement used in the grout; all other ingredients required in the grout will not be measured for payment. Concrete pavement removed will be measured in square yards {square meters} computed from surface measurements taken to the nearest 0.1 foot {0.1 meter}. Concrete pavement replacement slabs will be measured by computing the theoretical cubic yards {cubic meters} of concrete necessary to replace the removed slab. The thickness used in computing the theoretical cubic yards {cubic meters} will be the average thickness necessary to replace the slab and to fill any voids, except those caused by the Contractor, underneath the slab.
453.05 Basis of Payment.
a.Unit Price Coverage .
1.Drill Holes . Drill holes for stabilizing the concrete pavement, measured as noted above, will be paid for at the contract unit price bid per each which shall be full compensation for the drilling of the holes a nd the sealing of the holes after the satisfactory use thereof, and includes the furnishing of equipment, tools, labor, and incidentals necessary to complete this item of work.
2.Portland Cement Pressure Grout . Portland cement pressure grout, measured as noted above, will be paid for at the contract unit price bid per bag of cement used in the grout, which shall be full compensation for furnishing the grout, including all ingredients for the type mix designated, for the mixing, for pumping of the grout, and for all equipment, tools, labor, and incidentals necessary to complete this item of work.
454.01 Descriptio n.
3.Removal of Concrete Pavement Slabs . Removal of concrete pavement slabs, measured as noted above, will be paid for at the contract unit price bid per square yard {square meter}, which shall be full compensation for the sawing and satisfactory removal and disposal of the old concrete, for the reconditioning or replacement of all steel and the concrete joint including all equipment, tools, labor, and other incidentals necessary to complete this item of work.
4.Concrete Pavement Replacement Slabs . Concrete pavement replacement slabs, measured as noted above, will be paid for at the contract unit price bid per cubic yard {cubic meter} which shall be full compensat ion for the furnishing of the concrete mix, the hauling of the mix, the forming, placing, including any new steel, sawing and sealing of joints, finishing and curing of the slab and for all equipment, tools, labor, and incidentals necessary to complete thi s item of work.
5.Smoothness Acceptance . After the grouting operation, all surfaces shall receive grinding in accordance with Section 455 and shall meet the smoothness requirements of Subarticle 455.03e.
b.Payment will be made under Item No .: 453-A Drill Holes (Max. bid limited to $6.00 per Hole) - per each 453-B Portland Cement Pressure Grout - per bag (94 pounds {42 kg}) 453-C Removal of Concrete Pavement Slab - per square yard {square meter} 453-D Concrete Pavement Replacement Slab - per cubic ya rd {cubic meter} SECTION 454 CLEANING AND SEALING JOINTS AND CRACKS IN CONCRETE PAVEMENT
454.01 Description.
This Section shall cover the work of cleaning and sealing joints and cracks in existing concrete pavement. The shape of the joints shall be restored by sawing the concrete to allow the proper sealing of the joints. Cracks shall be sealed by the routing of a groove at the crack for the placement of sealant. The cleaning and sealing of joints and cracks will be classified by "Type" in accordance with the following: Type I: Cleaning and sealing of joints and cracks that will not be covered by a bituminous overlay. Type II: Cleaning and sealing of joints and cracks that will be covered by a bituminous overlay.
454.02 Materials.
The sealant shall be either a Hot Applied Joint Sealant or a Cold Applied Joint Sealant as shown on the plans. Joint sealants shall meet the requirements given in Section 832 for joint and crack sealants.
454.03 Construction Requirements.
a.Submittal of Equipment Data . The Contractor shall submit descriptions of all equipment proposed for use in sawing the joints, routing the cracks, cleaning the joints and cracks and placing the sealant. The submittal s hall also consist of the operational guidelines from the equipment manufacturer. The Contractor shall deliver the submittal to the Engineer for review. The Engineer will not approve the submittal but will review it for completeness. The Engineer will prohi bit the use of equipment that may damage the pavement or result in a joint or crack that cannot be sealed. Equipment shall not be brought to the worksite until the Engineer informs the Contractor that the submittal is complete.
b.Preparation of Joints for Sealant . The old joint sealant material and other debris shall be removed from the joint. Material placed to form an expansion joint during the original construction of the pavement shall not be removed. The joint shall then be cut with a concrete sa w to provide the shape and size of joint shown on the plans. The concrete saw shall be a saw that is designed for cutting concrete. If water is used to facilitate cutting, the resulting slurry shall be completely removed from the joint and the pavement
Source: Alabama Standard Specifications for Highway Construction, 2022 Edition. Pages 273–278 of 934.