No measurement will be made of unexposed surfaces such as support slabs at joints, integral curb faces, or cut -off walls. 912- 5 Basis of Payment: Payment for shotcrete will be made at the contract unit price per square yard, complete in place, including excavating, backfilling, fine grading, compaction, and reinforcement. SECTION 913 BANK PROTECTION: 913- 1 Description: The work under this section shall consist of furnishing all materials and constructing bank protection in accordance with the details shown on the plans and the requirements of the specifications. Bank protection shall be dumped riprap, grouted riprap, wire tied riprap, riprap in wire baskets or gabions, soil-cement, and other types of bank protection and shall be constructed at the locations and as shown on the project plans. 913- 2 Materials: 913- 2.01 Rip Rap Bank Protection :
A.Rock : Rock shall be sound and durable, free from clay or shale seams, cracks or other structural defects. The bulk (SSD) specific gravity of the rock shall be a minimum of 2.4 as determined in accordance with the requirements of Arizona Test Method 210, modified to specify that testing shall be performed on 3- inch maximum to plus N o. 4 size material. If required by the Engineer, the contractor shall break an adequate amount of rock down to 3- inch maximum size particles for performance of the necessary testing. Rock used to construct dumped riprap shall be angular in shape. Rock used to construct other types of bank protection may be rounded stones or boulders. Rock shall have a least dimension not less than one- third of its greatest dimension and a gradation in reasonable conformity with that shown herein for the various types of bank protection. Control of the gradation will be by visual inspection. When a source of rock is designated, it shall be the contractor's responsibility to negotiate for the material, obtain the right -of-way and pay all royalties and damages. TABLE OF CONTENTS INDEX The acceptability of the rock will be determined by the Engineer by visual inspection and/or testing. If testing is required, suitable samples of rock shall be taken in the presence of the Engineer at least 25 days in advance of its expected use. The approval of som e rock fragments from a particular quarry site shall not be construed as constituting the approval of all rock fragments taken from that quarry. During construction of the bank protection, the contractor shall provide two samples of rock for the intended use. The size of each sample for dumped riprap and riprap (slope mattress) shall be at least 5 tons. The size of each sample for grouted riprap, wire tied riprap, gabions, and rail bank protection shall be at least 500 pounds. One sample shall be provided at the construction site and may be a part of the finished bank protection. The other sample shall be provided at the quarry. These samples w ill be used as a frequent reference for judging the gradation of the rock supplied. Any difference of opinion between the Engineer and the contractor shall be resolved by checking the gradation of two random samples of the rock. Material that is deemed unsatisfactory by the Engineer shall be replaced with acceptable material at no additional cost to the Department.
1.Grouted Riprap: Gradation of the rock for grouted riprap shall be as specified in the Special Provisions or as shown on the project plans.
2.Wire Tied Riprap: Rock for wire tied riprap shall be well graded with at least 95 percent exceeding the least dimension of the wire mesh opening. The maximum size rock, measured normal to the mat, shall not exceed the mat thickness.
3.Dumped Riprap: Gradation of the rock for dumped riprap shall be as shown on the project plans or as specified in the Special Provisions. Mechanical equipment, a sorting site, and labor needed to assist in checking gradation shall be provided by the contractor at no additional cost to the Department.
4.Gabions: Rock for gabions shall be well graded, varying in size from 4 to 8 inches. TABLE OF CONTENTS INDEX
5.Riprap (Slope Mattress) : Rock for slope mattress shall be well graded with 70 percent exceeding 3 inches. The maximum dimension of a single rock shall not exceed the least dimension of the gabion.
6.Rail Bank Protection: Rock used to construct rail bank protection shall be well graded, varying in size from 4 to 12 inches.
B.Metal Items:
1.Wire Fabric: Welded wire fabric shall be galvanized and shall conform to the requirements of AASHTO M 55, except that the minimum weight of the zinc coating shall be 0.15 ounces per square foot of actual surface. Woven wire fabric shall be galvanized and shall conform to the requirements of ASTM A116, except that the minimum weight of the zinc coating shall conform to the requirements of ASTM A641, Class 3. Wire fabric shall be of the diameter, spacing, pattern, and dimensions shown on the plans. The selvage on each sheet of mesh shall be galvanized steel wire with a minimum di ameter 25 percent larger than that used in the body of the mesh. Certificates of Compliance conforming to the requirements of Subsection
106.05 of the specifications shall be submitted.
2.Miscellaneous Fittings and Hardware: Miscellaneous fittings and hardware shall be of the type and size provided by the manufacturer of the major item to which they apply and shall be galvanized in accordance with the requirements of AASHTO M 232. Certificates of Compliance conforming to the requirements of Subsection 106.05 of the specifications shall be submitted.
3.Tie Wires: Tie wires shall be of good commercial quality and the size shall be as shown on the project plans, except that the minimum weight of the zinc coating shall conform to the requirements of ASTM A641, Class 3. At the option of the contractor, approved wire fasteners may be used on gabions, slope mattresses, or wire fabric in lieu of tie wires. TABLE OF CONTENTS INDEX Certificates of Compliance conforming to the requirements of Subsection
106.05 of the specifications shall be submi tted.
4.Steel Cable: Steel cable shall be zinc- coated steel structural wire rope conforming to the requirements of ASTM A475, seven- wire strand, Class A, for the diameter shown on the plans. Certificates of Compliance conforming to the requirements of Subsection 106.05 of the specifications shall be submitted.
5.Railroad Rail: Railroad rails may be new or used. If used rails are furnished, they shall be free from rust and equal to at least 95 percent of the original section.
6.Soil Anchor Stakes: Soil anchor stakes shall be steel and of the length called for on the plans. When not specified to be railroad rails, the following items may be used: crane rails with a weight of at least 40 pounds per linear foot, 2-inch diameter steel pipe conforming to the requirements of ASTM A53, or 3 -inch by 3- inch by 3/8 -inch structural steel angles conforming to the requirements of ASTM A36. Used rails, pipe or angles may be used provided the material is not rusted or damaged to the extent that the strength of the item is reduced to less than 90 percent of a new item of the same type and size. Certificates of Compliance conforming to the requirements of Subsection
106.05 of the specifications shall be submitted.
C.Bedding Material: Bedding material shall consist of granular material having a maximum dimension of 2 inches and shall be free of clay or organic material.
D.Grout: Grout shall consist of Portland cement, aggregate, and water. It may also contain su pplementary cementitious material. Portland cement, aggregate, water, and supplementary cementitious material shall conform to the requirements of Section 1006 of the specifications. If approved by the Engineer, chemical admixtures may be used. Chemical admixtures shall conform to the requirements of Subsection 1006- 2.04 of the specifications, except no admixtures containing chlorides or nitrates shall be used. Air -entraining admixtures, conforming to the requirements of Subsection 1006- 2.04 of the specifications , will be required for grout placed at elevations of 3, 000 feet or above. TABLE OF CONTENTS INDEX The grout shall meet the requirements given in the table below. Minimum Cementitious Material Content: Lbs per CY (See Note 1) Maximum Water/Cementitious Material Ratio (w/cm): Lb./Lb. Slump: Inches (See Note 2) Air Content: Percent (See Note 3) 850 0.60 9 ± 2 0 – 8 Note s:
1.A maximum of 25 percent of the cementitious material, by weight, may consist of an approved Class F fly ash, conforming to the requirements of ASTM C618.
2.The slump shall be in the appropriate range to permit gravity flow into the interstices with limited spading and brooming. The consistency of the grout shall be as approved by the Engineer.
3.For placement of grout at elevations of 3 ,000 feet or above, the air content shall be a minimum of 4 percent and a maximum of 8 percent. The mix shall consist of fine aggregate; however, at the option of the contractor, No. 8 coarse aggregate may be used in the grout. If No. 8 coarse aggreg ate is used, the volume shall be a maximum of 35 percent of the total aggregate volume. For plant -mixed grout, the proportioning, mixing, and placing shall be in accordance with the applicable requirements in Section 1006 of the specifications. For on- site mixing, grout that has been mixed more than one hour shall not be used. Retempering of grout will not be permitted.
E.Bank Protection Fabric: Fabric shall be supplied in accordance with and conform to the material requirements of Subsections 1014- 1 and 1014- 5 of the specifications, respectively. Special attention shall be given to the required survivability of the fabric. The identification, packaging, handling, and storage of the geotextile fabric shall be in accordance with ASTM D4873. Fabric rolls shall be furnished with suitable wrapping for protection against moisture and extended ultraviolet exposure prior to placement. Each roll shall be labeled or tagged to provide product identification sufficient to determine the product type, manufacturer, quantity, lot number, roll TABLE OF CONTENTS INDEX number, date of manufacture, shipping date, and the project number and name to which it is assigned. Rolls will be stored on the site or at another identified storage location in a manner which protects them from the elements. If stored outdoors, they shall be elevated and protected with a waterproof, light colored, opaque cover. At no time, shall the fabric be exposed to sunlight for a period exceeding 14 days.
F.Sacked Concrete: Sacked concrete shall be utility concrete conforming to the requirements of Section 922 of the specifications, except that the minimum cement content shall be 376 pounds per cubic yard; the slump shall be from 3 to 5 inches; and the aggregate shall conform to the following gradation when tested in accordance with the requirements of Arizona Test Method 201: Sieve Size Percent Passing 2 inch 100 1/4 inch 45 - 89 No. 200 0 - 12.0 Sacks for sacked concrete riprap shall be made of at least AASHTO M 182, Class 3, burlap and shall be approximately 19- 1/2 by 36 inches measured inside the seams when the sack is laid flat, with an approximate capacity of 1.25 cubic feet. Sound, reclaimed sacks may be used. 913- 2.02 Soil -Cement Bank Protection:
A.Hydraulic Cement, Fly Ash, and Water: Hydraulic cement, fly ash, and water shall conform to the requirements of Subsection 1006 -2 of the specifications.
B.Soil -Aggregate: The source of soil -aggregate materials shall be the responsibility of the contractor. The contractor shall be solely responsible for the construction of the stockpile(s), including monitoring for quality and uniformity of the material placed therein. The soil -aggregate used in the soil-cement mixture shall consist of stone, gravel or other approved inert material of similar characteristics, and shall be clean and free from vegetable matter and other deleterious substances. Soil- cement aggregate shall conform to the following gradation requirements when tested in accordance with Arizona Test Method 201: Sieve Size Percent Passing 1-1/2 in 98 - 100 No. 4 60 - 90 No. 200 5.0 - 15.0 TABLE OF CONTENTS INDEX The Plasticity Index shall be a maximum of 5 when tested in accordance with the requirements of AASHTO T 90. Clay lumps larger than 1 inch shall be removed. When soil -aggregates are stored on the ground, the sites for the stockpiles shall be clear of all vegetation and level. The bottom 1 -foot layer of aggregate shall not be disturbed or used. The debris or waste material resulting from the clearing and preparing of the site shall be disposed of in accordance with Subsection 201- 3.02 of the specifications.
C.Mix Design Requirements for Soil -Cement Bank Protection: Utilizing soil- aggregate, cementitious material, and water, a mix design conforming to the requirements specified herein shall be formulated and submitted by the contractor to the Engineer for approval prior t o incorporating any of the material into the work. The amount of cement shall be determined by laboratory testing by the contractor in accordance with Arizona Test Method 220. For mix design purposes, the cement content of the soil -cement mixture shall be determined as the cement content which yields a seven day compressive strength of 1250 pounds per square inch for the soil -cement mixture. The percent of cement to be used in the mix shall be calculated to be the weight of cement di vided by the total weight of the dry compacted soil-cement. Included in the mix design data shall be the grade of cement, brand of fly ash, and the source of aggregate. A new mix design shall be submitted for approval any time the contractor requests a change in soil - aggregate source from that given in the approved mix designs. 913- 3 Construction Requirements: 913- 3.01 Rip Rap Bank Protection : Areas on which bank protection is to be constructed shall be cleared, grubbed, and excavated or backfilled in accordance with the requirements of the appropriate sections of Division II to produce a ground surface in reasonable conformance with the lines and grades shown on the project plans or established by the Engineer. Placement through water will not be permitted unless otherwise approved by the Engineer. TABLE OF CONTENTS INDEX SECTIO N 913 Areas which are excavated for installation of rail bank protection shall be backfilled to original ground or to the lines and grades shown on the plans.
A.Bank Protection Fabric: When fabric is required, it shall be placed in the manner and at the locations shown on the project plans. The surface to receive the fabric shall be free of obstructions, depressions and debris. T he fabric shall be loosely laid and not placed in a stretched condition. The strips shall be placed to provide a minimum 24 inches of overlap for each joint. On horizontal joints, the uphill strip shall overlap the downhill strip. On vertical joints, the upstream strip shall overlap the downstream strip. The fabric shall be protected at all times during construction from extensive exposure to sunlight. When the maximum size of the rock to be placed on fabric exceeds 18 inches, the fabric shall be protect ed during the placement of the rock by a layer of bedding material. The bedding material shall be spread uniformly on the fabric to a depth of 4 inches and shall be free of mounds, dips or windrows. Compaction of the bedding material will not be required. Rock shall be carefully placed on the bedding material and fabric in such a manner as not to damage the fabric. If, in the opinion of the Engineer, the fabric is damaged or displaced to the extent that it cannot function as intended, the contractor shal l remove the rock, regrade the area if necessary, and replace the fabric.
B.Dumped Riprap : The rock shall be placed to its specified thickness in one operation and in a manner which will produce a reasonably w ell graded mass with a minimum amount of voids and with the larger rock evenly distributed throughout the mass. No method of placing the rock that will cause segregation will be allowed. Hand placing or rearranging of individual rock may be necessary to obtain the specified results.
C.Wire -Tied Riprap: After installation of the lower portion of the wire mesh, rock shall be placed in accordance with the requirements of Subsection 913- 3.01(B) of the specifications. After placement of the rock, the upper portion of the wire mesh shall be placed, laced, and tied in accordance with the details shown on the project plans. TABLE OF CONTENTS INDEX
D.Grouted Riprap: Rock for grouted r iprap shall be placed in accordance with the requirements of Subsection 913- 3.01(B) of the specifications. The stones shall be thoroughly moistened and any excess of fines shall be sluiced to the underside of the stone blanket before grouting. The grout may be delivered to the place of final deposit by any means that will ensure uniformity and prevent segregation of the grout. If penetration of grout is not obtained by gravity flow into the interstices, the grout shall be spaded or rodded to completel y fill the voids in the stone blanket. Pressure grouting shall not unseat the stones, and during placing by this method, the grout shall be spaded or rodded into the voids. Penetration of the grout shall be to the depth specified on the project plans. When a rough surface is specified, stone shall be brushed until from 25 to 50 percent of the depth of the maximum size stone is exposed. For a smooth surface, grout shall fill the interstices to within 1/2 inch of the surface. Grout shall not be placed when the descending air temperature falls below 40 degrees F nor until the ascending air temperature rises above 35 degrees F. Temperatures shall be taken in the shade away from artificial heat. Curing of the grout shall be in accordance with the requirements of Subsection 912- 3.09 of the specifications. At the option of the contractor, shotcrete conforming to the requirements of Section 912 of the specifications may be furnished in lieu of grout.
E.Slope Mattress Riprap: The mattress bed shall be excavated to the width, line and grade as shown on the plans. The mattress shall be founded on this bed and laid to the lines and dimensions required. Excavation for toe or cut -off walls shall be made to the neat lines of the wall. Mattresses shall be fabricated in such a manner that the sides, ends, lid and diaphragms can be assembled at the construction site into rectangular units of the specified sizes. Mattresses are to be of single unit construction, the base, ends and sides either to be woven into a single unit or one edge of these members connected to the base section of the unit in such a manner that strength and flexibility at the point of connection is at least equal to that of the mesh. TABLE OF CONTENTS INDEX All perimeter edges of the mattresses are to be securely selvaged or bound so that the joints formed by tying the selvages have at least the same strength as the body of the mesh. Mattresses shall be placed to conform with the details shown on the project plans. Stone shall be placed in close contact within the unit so that maximum fill is obtained. The units may be filled by machine with sufficient hand work to accomplish the requirements of this specification. Broken concrete shall not be used in slope mattresses. Before the mat tress units are filled, the longitudinal and lateral edge surfaces of adjoining units shall be tightly connected by means of wire ties placed every 4 inches or by a spiral tie having a complete loop every 4 inches. The lid edges of each unit shall be connected in a similar manner to adjacent units. The slope mattress shall be anchored as shown on the project plans. Each anchor stake shall be fastened to the cover mesh with a tie wire.
F.Gabions: The gabion bed shall be excavated to the width, line and grade as shown on the plans. The gabions shall be founded on this bed and laid to the lines and dimensions required. Excavation for toe or cut -off walls shall be made to the neat lines of the wall. Gabions shall be fabricated in such a man ner that the sides, ends, lid and diaphragms can be assembled at the construction site into rectangular units of the specified sizes. Gabions are to be of single unit construction, the base, ends and sides either to be woven into a single unit or one edge of these members connected to the base section of the unit in such a manner that strength and flexibility at the point of connection is at least equal to that of the mesh. Where the length of the gabion exceeds its horizontal width, the gabion is to be eq ually divided by diaphragms, of the same mesh and diameter as the body of the gabions, into cells whose length does not exceed the horizontal width. The gabion shall be furnished with the necessary diaphragms secured in proper position on the base section in such a manner that no additional tying at this juncture will be necessary. All perimeter edges of gabions are to be securely selvaged or bound so that the joints formed by tying the selvages have at least the same strength as the body of the mesh. Gabi ons shall be placed to conform with the project plan details. Stone shall be placed in close contact in the unit so that maximum fill is TABLE OF CONTENTS INDEX obtained. The units may be filled by machine with sufficient hand work to accomplish requirements of this specificati on. The exposed face or faces shall be hand- placed using selected stones to prevent bulging of the gabion cell and to improve appearance. Each cell shall be filled in three lifts. Two connecting tie wires shall be placed as shown on the project plans betw een each lift in each cell. Care shall be taken to protect the vertical panels and diaphragms from being bent during filling operations. The last lift of stone in each cell shall be level with the top of the gabion in order to properly close the lid and provide an even surface for the next course. All gabion units shall be tied together each to its neighbor along all contacting edges in order to form a continuous connecting structure. Empty gabions stacked on filled gabions shall be laced to the filled gabion at the front, side and back.
G.Sacked Concrete Riprap: The sacks shall be filled with concrete, loosely packed so as to leave room for folding or tying at the top. Approximately 1 cubic f oot of concrete shall be placed in each sack. Immediately after filling, the sacks shall be placed according to the details shown on the project plans and lightly trampled to cause them to conform with the earth face and with adjacent sacks in place. The first two courses shall provide a foundation of double thickness. The first foundation course shall consist of a double row of stretchers laid level and adjacent to each other in a neatly trimmed trench. The trench shall be cut back into the slope a suff icient distance to enable proper subsequent placement of the riprap. The second foundation course shall consist of a row of headers placed directly above the double row of stretchers. The third and remaining courses shall consist of a double row of stret chers and shall be placed in such a manner that joints in succeeding courses are staggered. All dirt and debris shall be removed from the top of the sacks before the next course is laid thereon. Stretchers shall be placed so that the folded ends will not be adjacent. Headers shall be placed with the folds toward the earth face. Not more than four vertical courses of sacks shall be placed in any tier until initial set has taken place in the first course of any such tier. When there will not be proper bearing or bond for the concrete because of delays in placing succeeding layers of sacks, a small trench shall be excavated back of the row of sacks already in place, and the trench shall be filled with fresh concrete before the next layer of sacks is laid. The TABLE OF CONTENTS INDEX size of the trench and the concrete used for this purpose shall be approved by the Engineer. The Engineer may require header courses at any level to provide additional stability to the riprap. Sacked concrete riprap shall be cured by being covered with a blanket of wet earth or by being sprinkled with a fine spray of water every two hours during the daytime for a period of four days.
H.Rail Bank Protection: Excavation, where required for rock fill, shall be per formed in reasonably close conformity to the lines and grades established or shown on the plans. Rails shall be driven at the locations and to the minimum penetrations shown on the plans. Driving equipment shall be capable of developing sufficient energy to drive the rails to the specified minimum penetration and be approved by the Engineer. If hard material is encountered during driving before minimum penetration is reached and it has been demonstrated to the satisfaction of the Engineer that additional attempts at driving would result in damage to the rails, the Engineer may order additional work to be performed, such as jetting or drilling, in order that minimum penetration may be obtained or the Engineer may order the minimum penetration to be reduced a s required by the conditions encountered. Wire fabric shall be securely fastened to the rails, placed in the trenches and laid on the slopes. The rock backfill shall then be carefully placed so as not to displace the wire fabric or rails. The wire fabric shall entirely enclose the rock backfill. The completed rock fill shall be backfilled as necessary and the waste material disposed of as directed by the Engineer. 913- 3.02 Soil -Cement Bank Protection: Soil -cement bank protection construction shall include excavating, backfilling, and grading the wash bed and banks to the lines, grades and cross sections shown on the project plans or established by the Engineer; furnishing and mixing aggregate, cement, fly ash and water; and spreading, compacting, and curing the mixture. The contractor shall investigate for ground water as soon as possible. If there is a need for dewatering, the contractor shall provide to the Engineer for review a comprehensive dewatering plan a minimum of two weeks before construction starts. The dewatering plan shall address any water quality requirements of the Corps of Engineers permit and ADEQ certification. Dewatering activities shall not begin until the Engineer has approved the plan. TABLE OF CONTENTS INDEX The dewatering shall comply with all laws and permit requirements. If changes to the approved dewatering plan are required, the contractor shall submit a revised plan to the Engineer for approval. For soil -cement bank protection the contractor shall be responsible for quality control as necessary t o meet the requirements established herein. The contractor shall monitor the complete mix during construction of soil -cement, including the amounts of cement and fly ash used.
A.Required Contractor Submittals: Two weeks prior to the start of the soil -cement bank protection construction, the contractor shall submit in writing to the Engineer for approval, the following items:
1.The type of compaction equipment to be used;
2.The number and type of watering equipment to be used;
3.The method used to keep surfaces continuously moist until subsequent layers of soil -cement are placed;
4.The method used to cure permanently exposed surfaces;
5.The proposed source of soil -aggregate ;
6.The proposed source(s) of Portland cement and fly ash (if used) ;
7.The approximate length of soil -cement bank protection or area of soil -cement to be placed each day prior to starting placement and compaction operations, on a daily basis; and
8.The soil -cement mix design. Such submittals shall not relieve the contractor of the responsibility for achieving the desired result of constructing sound soil -cement, free from defects, according to the specifications and plans, or as directed by the Engineer. Changes in the source(s) of cement or fly ash will not be permitted without the prior approval of the Engineer.
B.Preparation of Subgrade: Before placement of the soil -cement, the area to be treated shall be graded and shaped to the lines and grades as shown on the plans. The subgrade shall be compacted to a minimum of 95 percent of the maximum dry density determined in accordance with Arizona Test Method 225. TABLE OF CONTENTS INDEX The subgrade shall be compacted at a moisture content within 2 percentage points of the optimum moisture content determined in accordance with Arizona Test Method 225. When the embankment material is composed predominantly of rock such that these compaction control procedures will not indicate the density achieved, the Engineer will determine the amount of compaction required and the adequacy of equipment used in obtaining the required compaction. Immediately prior to placement of the soil -cement mixture, the subgrade within the lines and grades of the plans shall be moistened and any soft or yielding subgrade shall be corrected and made stable before construction proceeds in accordance with requirements of Subsection 203- 5.03(A) of the specifications. Any additional subgrade reparations required outside of the lines and grades shown on the plans, as determined by the Engineer, shall be repaired by the contractor and paid for by Force Account.
C.Mixing Plant: Aggregate and cementitious materials for the soil -cement shall be proportioned and mixed in a central mixing plant. The plant shall be either of the batch- mixing type using revolving blade, rotary drum mixers, or of the cont inuous mixing type using a stationary twin shaft pug mill mixer, at the option of the contractor. The aggregate, fly ash, and cement shall be proportioned by weight. The mixing plant shall be designed, coordinated, and operated to produce a soil -cement m ixture of the proportions specified within required tolerances. If the soil -cement temperatures measured at the mixer are 85 degrees F or less, the placing and compaction shall be completed within 1- 1/2 hours of the batch time. If soil -cement temperatures measured at the mixer are greater than 85 degrees F but less than 91 degrees F, placing and compaction shall be completed within 1 hour of the batch time. If soil-cement temperatures are 91 degrees F or greater when measured at the mixer, the contractor shall take immediate steps to lower the batch plant mix temperature to 90 degrees F or below, and follow the above time limits as mix temperature dictates, prior to further placement and compaction of soil -cement materials. The water shall be proportioned by weight or volume and there shall be means by which the Engineer may readily verify the amount of water utilized per batch or the rate of water flow utilized for continuous mixing.
1.Measuring Devices: The mixing plant shall record the quantity of the materi al, shall have a digital readout, and shall provide an hourly printed record such that the total discharged quantity per hour and the cumulative total quantity are displayed. Measuring devices shall be calibrated and approved by the Engineer. TABLE OF CONTENTS INDEX Each weight measuring device shall be calibrated to an accuracy of 0.2 percent and shall be inspected and calibrated as often as the Engineer deems necessary to assure their accuracy. Each volume measuring device shall be calibrated to an accuracy of ± 1.5 per cent and shall be inspected and calibrated as often as the Engineer deems necessary to assure their accuracy.
2.Batch Mixing: The mixer shall be equipped with a sufficient number of paddles of a type and arrangement to produce a uniformly mixed batch. The m ixer shall be equipped with a timing device which will indicate, by a definite audible or visual signal, the expiration of the mixing period. The device shall be accurate to within two seconds. The allowable tolerance for weight batching of aggregates and cementitious material shall be 2.0% and 0.5%, respectively, for each batch. The batch mixing plants shall provide sampling facilities which are satisfactory to the Engineer and which allow representative samples of the soil -aggregate mixture prior to the addition of water and cementitious material to be obtained easily and safely. Samples of the soil -aggregate will be taken at this point to determine conformance to the gradation and plasticity requirements listed in Subsection 913- 2.02(B) of the specificat ions.
3.Continuous Mixing: Aggregates shall be drawn from the storage facility by a feeder or feeders which will continuously supply the correct amount of soil - aggregate in proportion to the cementitious material. A control system shall be provided that wi ll automatically close down the plant when material in any storage facility approaches the strike off capacity of the feed gate. The plant will not be permitted to operate unless this automatic control system is in good working condition. The feeder for the soil -aggregate shall be mechanically or electrically driven. Continuous mix plants shall provide sampling facilities which are satisfactory to the Engineer and which allow representative samples of the soil -aggregate mixture prior to the addition of wa ter and cementitious material to be obtained easily and safely. Samples of the soil -aggregate will be taken at this point to determine conformance to the gradation and plasticity requirements listed in Subsection 913- 2.02(B) of the specifications.
4.Blend ing of Cement and Fly Ash: The blending procedure shall be sufficient to provide a uniform, thorough, and consistent blend of cement and fly ash. The blending method and operation shall be approved by the Engineer prior to the commencement of soil -cement production. During blending of the TABLE OF CONTENTS INDEX cementitious materials, the percent of fly ash content shall not vary by more than ± 0.5 percent of the content approved by the Engineer. Weight measuring devices are required at both the cement and fly ash feeds. At th e direction of the Engineer, an additional measuring device may also be required when the cement and fly ash are pre- blended at the site. In the production of the soil -cement mixture, the percent of cementitious material shall not vary by more than ± 0.5 percent of the contents approved by the Engineer. Silos and feeders shall be equipped and operated so as to provide uniform rates of feed and prevent caking. The charge in the batch mixer or rate of feed to the continuous mixer shall not exceed that which will permit complete mixing of all the mix material. Provisions shall be made to allow for ready sampling of the cementitious materials.
D.Spreading: The soil -cement mixture shall be transported from the mixing plant to the construction site in clean haul ing equipment vehicles outfitted with suitable covers to protect the mixture in unfavorable weather. Spreading shall be accomplished by the use of approved scrapers, bulldozers, or motor graders. The layers of soil -cement shall not exceed 12 inches after c ompaction, or be less than 4 inches thick after compaction, unless the contractor can demonstrate the ability to place thicker layers with the equipment being utilized in the control strip. If potholing is performed to allow testing of each lift, the recompacted material used to repair the pothole shall also be tested and meet the requirements of this specification. Each successive layer shall be placed as soon as practicable after the preceding layer is completed, and approved by the Engineer. The maximum depth of compacted soil -cement that shall be placed per day is 4 feet, unless approved by the Engineer. Prior to spreading new material on a previously compacted lift which has cured for more than 1- 1/2 hours, or if the surface has dried due to temperature and/or wind effects, scarification of the lift shall be performed parallel with the direction of placement using equipment approved by the Engineer. The scarification shall be performed to a depth of at least 2 inches, spaced between 18 and 24 inches. The Engineer may waive requirements for scarification if compaction is performed by means which provide an appropriate surface for bonding with the subsequent layer. All construction equipment, including water spray trucks, shall be restricted from entering scarified surface areas during the interim between spreading and compaction operations. If the surface cannot be scarified, the surface shall have a cement grout slurry applied to ensure a proper bonding between lifts. The cement slurry shall have a water/cement ratio between 0.70 and 0.80 and be approved for use by the Engineer prior to placement of any additional soil-cement mixture. TABLE OF CONTENTS INDEX All soil- cement surfaces that will be in contact with succeeding layers of soil-cement shall be kept continuously moist by fog spraying until placement of the subsequent layer, provided that the contractor will not be required to keep such surfaces continuously moist for a period longer than seven days. Mixing and pl acing shall not proceed when the soil - aggregate or the area on which the soil -cement is to be placed is frozen. Soil -cement shall be mixed and placed when the air is at least 40 degrees F and rising.
E.Monitoring Moisture Content in the Field: Control of water content by the contractor in the field shall be accomplished in two ways:
1.The moisture- density relationship for the soil -cement mixture shall be determined in accordance with Arizona Test Method 221 on a routine basis, or when any signific ant gradation shift or rock content change occurs.
2.The actual moisture content of the mixture at the time of compaction, or shortly thereafter, shall be determined in accordance with Arizona Test Method 235 to determine if the optimum moisture content as determined by Arizona Test Method 221 is being maintained. The water content in the soil -cement mixture is to be continuously monitored, and the mixing water shall be adjusted at the plant as necessary to achieve the compressive strength and compaction req uirements specified herein.
F.Quality Control Compaction Testing: Soil -cement shall be uniformly compacted to a minimum of 98 percent of the maximum dry density determined in accordance with Arizona Test Method 221. A running average of five consecutive in place density tests shall not be less than 100 percent of maximum density as monitored by nuclear density tests in accordance with Arizona Test Method 235. Compaction shall be performed within 2 percentage points of the optimum moisture content as determi ned in accordance with Arizona Test Method 221. Quality control density and moisture tests shall be performed in accordance with Arizona Test Method 235 at a minimum frequency as specified in the following table: Quality Control Minimum Requirements for C ompaction Moisture/Density 1 test / 500 sy / lift
G.Control Strips: A control strip shall be constructed at the beginning of work on the soil - cement to be compacted. The control strip construction shall be required to establish equipment and procedures required to attain densities for the specified course. TABLE OF CONTENTS INDEX Each control strip, constructed to acceptable density and surface tolerances shall remain in place and become a section of the completed embankment. Unacceptable control strips shall be corrected or removed and replaced at the contractor's expense. A control strip shall have an area of approximately 100 square yards and shall be of the same depth specified for the construction of the course which it represents. The materials used in the construction of the control strip shall conform to the specification requirements. They shall be furnished from the same source and shall be of the same type used in the remainder of the course represented by the control strip. The underlying surface upon which a control strip is to be constructed shall have prior approval of the Engineer. The equipment used in the construction of the control strip shall be approved by the Engineer and shall be of the same type and weight to be used on the remainder of the course represented by the control strip. Compaction of control strips shall commence immediately after the course has been placed to the specified thickness, and shall be continuous and uniform over the entire surface. Compaction of the control strip shall be continued until no discernable increase in density can be obtained by additional compaction effort. Upon completion of the compaction, the mean density of the control strip will be determined by averaging the results of ten nuclear density tests taken at randomly selected sites within the control strip. If the mean density of the control strip is less than 100 percent of the density of laborator y compacted specimens as determined by testing procedures appropriate for the material being placed, the Engineer may order the construction of another control strip. A new control strip may also be ordered by the Engineer or requested by the contractor when:
1.A change in the material or mix design is made; and/or
2.A control strip density is not representative of the material being placed.
H.Power Tampers and Small Vibratory Rollers: Small vibratory rollers which are capable of operating within 6 inches of a vertical face shall be used for compaction adjacent to the guide banks, next to the utilities and drainage conduit; at transitions to constructed levee protection, and at other areas where larger vibratory rollers cannot maneuver. The amount of rolling and tamping required shall be whatever is necessary for the particular equipment to provide the same degree of compaction as would be attained with larger self -propelled TABLE OF CONTENTS INDEX vibratory rollers. Standby replacement equipment shall be available within 1 hour if needed.
I.Finishing/Trimming: After compaction, the soil -cement shall be further shaped, if necessary, to the required lines, grades, and cross- sections and rolled to a reasonably smooth surface. Shaping of the face of the soil -cement bank protection shall be conducted daily at the completion of each day’s production. The exposed face of the soil -cement bank protection shall be trimmed to a neat line as shown on the plans. The resulting soil -cement bank protection width shall not be less than 8 feet after trimm ing unless specified on the plans.
J.Curing: Whenever the atmospheric temperatures are expected to drop below 30 degrees F, the soil -cement shall be protected from freezing for seven days, after its construction by a covering of straw, earth, or other suitable material approved by the Engineer. Temporarily exposed surfaces shall be kept moist as previously set forth. Care must be exercised to ensure that no curing material other than water is applied to the soil -cement surface that will be in contact with succeeding layers. Permanently exposed surfaces shall be kept in a moist condition for seven days, or they may be covered with bituminous curing material, subject to the Engineer's approval. Any damage to the protective covering within seven days shal l be repaired to the satisfaction of the Engineer at no additional cost to the Department. Regardless of the curing material used, the permanently exposed surfaces shall be kept moist until the protective cover is applied. Such protective cover is to be a pplied as soon as practicable, with a maximum time limit of 24 hours between the finishing of the surface and the application of the protective cover or membrane.
K.Backfill: Backfill shall not be placed against the soil -cement until it has achieved its ful l design strength. After full design strength is achieved, special care shall be taken when placing backfill against the soil -cement to prevent damage. TABLE OF CONTENTS INDEX
L.Maintenance: The contractor shall maintain and protect the soil -cement in good condition until all work is completed and accepted. Maintenance shall include immediate repairs of any defects that may occur. This work shall be done at no cost to the Deparment and repeated as often as necessary. Faulty work shall be replaced for the full depth of the layer. The contractor shall take all necessary precautions to avoid damage to the completed soil -cement by equipment, and to avoid the deposition of raw earth or foreign materials between layers of soil - cement. Where ramps are constructed over soil -cement which are not to grade, all foreign materials and the uppermost 1 inch of the previously placed soil -cement mixture must be removed prior to continuation of the soil-cement construction.
M.Construction Joints: Construction joints are to be provided at the end of each day's work or when work is to be halted for 90 minutes or more. The joints shall be trimmed to a 15 degree minimum skew, transverse construction joint shall be formed by cutting back into the completed work to form a vertical face to the full depth of the previous lift. Before resuming placement of new material, the joints shall be roughened and loose material shall be removed by power broom.
N.Acceptance of Soil -Cement: The Engineer will cast, transport, cure, and test specimens in accordance with Arizona Test Method 241 for each 1,500 cubic yards of soil cement placed. Three cylinders will be tested at seven days. The average compressive strength of the three cylinders shall achieve a minimum compressive strength of 750 pounds per square inch . Any early strength testing for the purpose of correlating seven day strength results to provide an early indicator of potentially low strength material shall be the responsibility of the contractor. 913- 4 Method of Measurement: Riprap, except gabions a nd sacked concrete, will be measured by the cubic yard of protection constructed by computing the surface area measured parallel to the protection surface and the total thickness of the riprap measured normal to the protection surface. Riprap (gabions) wil l be measured by the cubic yard by computing the volume of the rock- filled wire baskets used. Riprap (sacked concrete) will be measured by the cubic yard of concrete placed in the completed work. The measurement will be based on mixer volumes. TABLE OF CONTENTS INDEX Rail bank protection will be measured by the linear foot. Measurement will be made from top of rail to top of rail (longest rail where rails of two or more lengths are used) and the distance measured will be from end rail to end rail. Where two parallel rows of vert ical rails are used, the measurement for payment will be the average of the distance along the two rows. Rail bank protection will be measured along the bank protection control line from end rail to end rail. Soil -cement will be measured per cubic yard of soil-cement furnished and placed per the specified lines, grades, and cross- sections shown on the plans. 913- 5 Basis of Payment: The accepted quantities of riprap and rail bank protection, measured as provided above, will be paid for at the contract unit price per cubic yard or linear foot, which price shall be full compensation for the work, complete in place, including excavation; preparing the ground area; furnishing and installing the rock, filter fabric, bedding material, metal items, concrete, sacks and grout; and backfilling as required. Materials, labor and equipment necessary to perform additional work such as jetting or drilling, as specified under Subsection 913- 3.01(H) of the specifications, will be paid for in accordance with the provisions of Subsection 109.04 of the specifications. The accepted quantities of soil -cement, measured as provided above, will be paid for at the contract unit price per cubic yard of soil -cement bank protection. Such payment shall constitute full reimbursement for all work necessary to complete the soil -cement bank protection including:
A.Surface Preparation;
B.Providing and Stockpiling Soil -Aggregate ;
C.Cementitious Material, Watering, Mixing ;
D.Placin g;
E.Compacting ;
F.Shaping and Finishing ;
G.Curing ;
H.Quality Control Testing ; and
I.Other Incidental Operations Any waste and non- compacted soil -cement material not used on the final soil-cement bank protection will not be measured for payment. Excavation and backfill associated with the soil -cement constructi on will be measured and paid under Structural Excavation and Structure Backfill items respectively. TABLE OF CONTENTS INDEX
Source: Arizona Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages – of 1,296.