Division VIII — Miscellaneous Construction
72 SLOPE PROTECTION
72-1 General
72-1.01 General
Section 72 -1 includes general specifications for constructing slope protection .
72-1.02 Materials
Construct slope protection or slope paving using minor concrete. Unless otherwise specified, fabric must be Class 8 RSP fabric.
72-1.03 Construction
Earthwork must comply with section 19. If placement of fabri c is required, place the fabric before placing slope protection, slope paving, and gabions. Before placing the fabric, the surface of the slope must be free of loose or extraneous material and sharp objects that may damage the fabric. Handle and place the fabric under manufacturer's instructions. Place the fabric loosely on the slope such that it conforms to the surface without damage to the fabric when the cover material is placed. Join the edges of the fabric with either overlapped joints or stitched seam s. If the fabric is joined with overlapped joints, the adjacent borders of the fabric must be overlapped by at least 24 inches. Overlap in the same direction that the cover material is placed. If the fabric is joined by stitched seams, stitch with contrast ing colored yarn. Use the size and composition of yarn that is recommended by the fabric manufacturer. Use 5 to 7 stitches per inch of seam. The strength of a stitched seam must be the same as that specified for the fabric, except if the stitched seams are oriented up and down a slope, the strength may be reduced to a value that it is at least 80 percent of that specified for the fabric. Do not operate equipment or drive vehicles directly on the fabric. If the fabric is damaged and the Engineer determines t hat it cannot be repaired, replace the fabric. If the Engineer determines that the fabric can be repaired, then repair it by covering the damaged area with new fabric. If the repair is made using overlapped joints, the overlap must be at least 3 feet.
72-1.04 Payment
The Department does not pay for additional fabric used for overlaps. Payment for rock slope protection fabric is not included in the payment for rock slope protection.
72-2 Rock Slope Protection
72-2.01 General
Use the class of rock and the method for placement described.
72-2.02 Materials
72-2.02A General
Reserved
72-2.02B Rock
For method A and B placement and the class of RSP described, comply with the rock gradation shown in the following table: SECTION 72 SLOPE PROTECTION Rock Gradation Nominal RSP class by median particle diameterb Nominal median particle weight c,dW50d15c (inch) d50c (inch) cd100 (inch) Placement Classa Diameter (inch) Min Max Min Max Max Method I 6 20 lb 3.7 5.2 5.7 6.9 12.0 B II 9 60 lb 5.5 7.8 8.5 10.5 18.0 B III 12 150 lb 7.3 10.5 11.5 14.0 24.0 B IV 15 300 lb 9.2 13.0 14.5 17.5 30.0 B V 18 1/4 ton 11.0 15.5 17.0 20.5 36.0 B VI 21 3/8 ton 13.0 18.5 20.0 24.0 42.0 A or B VII 24 1/2 ton 14.5 21.0 23.0 27.5 48.0 A or B VIII 30 1 ton 18.5 26.0 28.5 34.5 48.0 A or B IX 36 2 ton 22.0 31.5 34.0 41.5 52.8 A X 42 3 ton 25.5 36.5 40.0 48.5 60.5 A XI 46 4 ton 28.0 39.4 43.7 53.1 66.6 A aFor RSP Classes I –VIII, use Class 8 RSP fabric. For RSP Classes IX –XI, use Class 10 RSP fabric. bIntermediate or B dimension (i.e., width) where A dimension is length and C dimension is thickness. cd%, where % denotes the percentage of the total weight of the graded material. dValues shown are based on the minimum and maximum particle diameters shown and an average specific gravity of 2.65. Weight will vary based on specific gravity of rock available for the project. Rock material must comply with the requirements shown in the following table: Rock Material Requirements Quality characteristic Test method Requirement Apparent specific gravity (min) California Test 206 2.5 Absorption (max, %) California Test 206 4.2 Durability index (min) California Test 229 52 NOTES : Durability absorption ratio (DAR) = course durability index/(percent absorption + 1) If the DAR is greater than 10, the absorption may exceed 4.2 percent. If the DAR is greater than 24, the durability index may be less than 52. Select rock such that the shapes provide a stable structure for the required section. If the slope is steeper than 2:1, do not use rounded boulders and cobbles. Angular shaped rock may be used on any planned slope. Flat or needle -shaped rock mus t not be used unless the individual rock thickness is greater than 0.33 times the length.
72-2.02C Fabric
Fabric must be RSP fabric that complies with the class shown in the following table: Fabric Class Class Largest rock gradation class used in slope protection 8 Classes I –VIII 10 Classes IX –XI
72-2.03 Construction
72-2.03A General
Local surface irregularities of the RSP must not vary from the planned slope by more than 1 foot as measured at right angles to the slope. At the completion of slope protection work, fill voids in the footing trench with excavated material. Compaction is not required. SECTION 72 SLOPE PROTECTION
72-2.03B Placement Method A
Do not place rocks by dumping. Place larger rocks in the footing trench. Place rocks on the slope such t hat their longitudinal axis is normal to the face of the embankment. Place foundation course rocks such that they are in contact with the ground surface. For rocks above the foundation course, place them such that each rock has a 3 -point bearing on underly ing rocks; do not bear them on smaller rocks which may be used for chinking voids.
72-2.03C Placement Method B
Rocks may be placed by dumping and may be spread in layers by bulldozers or other suitable equipment. Place rocks such that:
1.There is a minim um of voids
2.Larger rocks are in the toe course and on the outside surface of the slope protection
72-2.04 Payment
If RSP is paid by the ton, the payment quantity is the weight determined from scale weighings. If RSP is paid by the cubic yard, the paym ent quantity is the volume determined from the dimensions shown or ordered.
72-3 Concreted -Rock Slope Protection
72-3.01 General
Section 72 -3 includes specifications for constructing concreted -rock slope protection . Use the class of rock and the method for placement described.
72-3.02 Materials
72-3.02A General
Reserved
72-3.02B Concrete
If colored slope protection is described, color the concrete by mixing a fine, ground, synthetic mineral oxide into the concrete. The synthetic mineral oxide must be specifically manufactured for coloring concrete. The color of the completed concrete after curing and when air dry must match color no. 30450 of AMS - STD-595. Use the 1-inch-maximum combined aggregate gradation in the concrete. The water content of the concrete must allow gravity flow into the interstices with limited spading and brooming.
72-3.02C Rock
Rocks for concreted -rock slope protection must comply with the gra dation shown in the following table: SECTION 72 SLOPE PROTECTION Concreted -Rock Gradation Nominal RSP class by median particle diameterb Nominal median c,dparticle weight W 50d15c (inch) d50c (inch) cd100 (inch) Classa Size (inch) Weighta Min Max Min Max Max I 6 20 lb 3.7 5.2 5.7 6.9 12.0 II 9 60 lb 5.5 7.8 8.5 10.5 18.0 III 12 150 lb 7.3 10.5 11.5 14.0 24.0 V 18 1/4 ton 11.0 15.5 17.0 20.5 36.0 VII 24 1/2 ton 14.5 21.0 23.0 27.5 48.0 aUse Class 8 RSP fabric. bIntermediate or B dimension (i.e., width) where A dimension is length and C dimension is thickness. cd%, where % denotes the percentage of the total weight of the graded material. dValues shown are based on the minimum and maximum particle diameters shown and an assumed specific gravity of 2.65. Weight wi ll vary based on specific gravity of rock available for the project. Rock for concreted -rock slope protection must comply with the requirements shown in the following table: Rock Material Requirements Quality characteristic Test method Requirement Apparent specific gravity (min) California Test 206 2.5 Absorption (max, %) California Test 206 4.2 Durability index (min) California Test 229 52 NOTES: Durability absorption ratio (DAR) = course durability index/(percent absorption + 1) If the DAR is greater than 10, the absorption may exceed 4.2 percent If the DAR is greater than 24, the durability index may be less than 52 Select rock such that the shapes provide a stable structure for the required section. If the slope is steeper than 2:1, do not use rounded boulders and cobbles. Angular shaped rock may be used on any planned slope. Flat or needle -shaped rock must not be used unless the individual rock thickness is greater than 0.33 times the length.
72-3.02D Weep Tubes
Weep tubes must:
1.Be schedule 80, perforated PVC pipe complying with section 68 -2.02D
2.Have a 2 -inch nominal diameter
72-3.03 Construction
72-3.03A General
Mix the coloring agent uniformly and homogeneously with the concrete. Local surface irregularities of the concreted -rock slope protection must not vary from the planned slope by more than 1 foot as measured at right angles to the slope. At the completion of slope protection work, fill voids in the footing trench with excavated mat erial. Compaction is not required.
72-3.03B Placement Method A
Placement Method A must comply with section 72 -2.03B.
72-3.03C Placement Method B
Placement Method B must comply with section 72 -2.03C.
72-3.03D Placing Weep Tubes
Wrap each weep tube in filter fabric. SECTION 72 SLOPE PROTECTION Place weep tubes and secure them such that they contact the face of the fabric on the slope and extend at least 2 inches beyond the outer surface of the rock. If placement of fabric on the slope is not required, the end of the tube near the slope must be covered with a cap made of the same material as the weep tube. Ensure that concrete will not plug the tube and perforations.
72-3.03E Placing Concrete
The surface of the rock to be concreted must be cleaned of adhering soil and then moistene d. At any one location, place the concrete in a continuous operation during a workday. Deposit concrete by use of chutes, tubes, buckets, pneumatic equipment, or other mechanical methods. Do not allow the concrete to flow more than 10 feet across the slope protection. Immediately after depositing, spade and rod the concrete into place with suitable spades, trowels, or other suitable means. The minimum concrete penetration must comply with the requirements shown in the following table: Minimum Concrete Penet ration Rock class VII V III II I Penetration (inch) 18 14 10 8 6 After placing the concrete, thoroughly brush the rocks to expose the top surfaces. Outer rocks must project above the concrete by a height of 0.25 –0.32 times the rock diameter. After completion of any 10 - foot strip, do not allow workmen or loads on the surface for at least 24 hours. Cure the concreted -rock slope protection by one of the methods specified for curing concrete . As an alternative, you may cure the concreted -rock slope protection by sprinkling a fine spray of water every 2 hours during the daytime for a period of 3 days. If colored concrete is described and you use the curing compound method, apply curing compound no. 6.
72-3.04 Payment
If concreted -rock slo pe protection is paid by the ton, the payment quantity is the weight determined from scale weightings. If concreted -rock slope protection is paid by the cubic yard, the payment quantity is the volume determined from the dimensions shown or ordered.
72-4 Small-Rock Slope Protection
72-4.01 General
Section 72 -4 includes specifications for constructing small -rock slope protection .
72-4.02 Materials
Rock must be cobble, gravel, crushed gravel, crushed rock, or any combination of these. If the rock layer is shown as 7 inches thick, comply with the gradation requirements shown in the following table: Rock Gradation for 7 -inch-Thick Layer Sieve size Percentage passing 5" 100 4" 90–100 3" 25–40 2" 0–10 If the rock layer is shown as 5 inches thick, comply with the gradation requirements shown in the following table: SECTION 72 SLOPE PROTECTION Rock Gradation for 5 -inch-Thick Layer Sieve size Percentage passing 4" 100 3" 90–100 2" 25–40 1" 0–10 If the rock layer is shown as 4 -inches thick, comply with gradation requirements shown in the following table: Rock Gradation for 4 -inch Thick Layer Sieve size Percentage passing 3" 100 2" 90–100 1" 25–40 3/4" 0–10 Granular material must contain at least 90 percent crushed particles when tested under California Test 205.
72-4.03 Construction
Local surface irregularities of the small -rock slope protection must not vary from the planned slope by more than 2 inches as measured at right angle s to the slope. Small rocks may be placed by dumping and may be spread by bulldozers or other suitable equipment. During spreading, do not crack the rock.
72-4.04 Payment
The payment quantity for small -rock slope protection is the volume determined from t he dimensions shown or ordered.
72-5 Concrete Slope Protection, Gutter Lining, Ditch Lining, and Channel Lining
72-5.01 General
Section 72 -5 includes specifications for shaping slopes, preparing the foundation, and constructing any of the following :
1.Concrete slope protection
2.Lined gutters
3.Ditch linings
4.Channel linings
5.Support walls
6.Cut-off stubs
7.Cut-off walls
8.Footings
9.Aprons Construct slope protection, gutter lining, ditch lining, and channel lining using minor concrete or shotcrete. Reinfor cement must comply with section 52.
72-5.02 Materials
Pervious backfill material must comply with section 19 -3.02D. Expansion joint filler must comply with section 51 -2.01B(1). Shotcrete must comply with section 53. SECTION 72 SLOPE PROTECTION If colored slope protection is describe d, color the concrete by mixing a fine, ground, synthetic mineral oxide into the concrete. The synthetic mineral oxide must be specifically manufactured for coloring concrete. The color of the completed concrete after curing and when air dry must match col or no. 30450 of AMS - STD 595 . Weep tubes must:
1.Be schedule 80, perforated PVC pipe comply ing with section 68 -2.02D
2.Have a 2 -inch nominal diameter
72-5.03 Construction
Evenly grade t he foundation, includ ing all surfaces where concrete is to be place d, such that no point on the graded surface is above the designated plane. Wrap each tube in fabric. Place weep tubes as shown or ordered. Placing concrete must comply with section 51. At each weep tube and drain hole, place a securely tied sack that conta ins 1 cubic foot of pervious backfill. The sack material must comply with the specifications for fabric in section 72 -2.02C . Mix the coloring agent uniformly and homogeneously with the concrete. Spread and tamp concrete until it is thoroughly compacted and mortar flushes to the surface. If the slope is too steep to allow the use of concrete wet enough to flush with tamping, tamp concrete until it is consolidated and immediately trowel on a mortar surface that is 1/4 inch thick. The mortar must consist of 1 part portland cement or portland limestone cement and 3 parts fine aggregate. After striking -off to grade, hand -float the concrete with floats that are at least 4 inches wide and 30 inches long. Broom the entire surface with a stiff -bristle br oom to produce a uniform surface. Brooming must be done when the surface is set enough to prevent deep scarring and must be accomplished by drawing the broom down the slope, leaving marks parallel to the edge of the slope. The Engineer may direct you to apply a fine spray of water to the surface immediately before brooming. Edges and joints must be edged with a 1/4 -inch-radius edger before the brooming. Install transverse expansion joints at 20 -foot intervals. Fill the expansion joints with 1/2 -inch-thick expansion joint filler. After placing the concrete, fill the footing trenches with excavated material. Compaction is not required. Cure concrete slope protection, gutter lining, ditch lining, and channel lining by with one of the methods specified for curin g concrete . If colored concrete is described and you use the curing compound method, apply curing compound no. 6. Construct, finish, and cure shotcrete slope protection under section 53.
72-5.04 Payment
The payment quantity for concrete (slope protection) constructed with minor concrete or shotcrete is the product of (1) the a rea measured along the slope lines of the completed concrete slope protection and (2) the thickness shown for the concrete slope protection . The Department does not pay for additional concrete placed due to over excavation.
72-6 Broken -Concrete Slope Protection
Reserved SECTION 72 SLOPE PROTECTION
72-7 72-10 Reserved
72-11 Slope Paving
72-11.01 General
72-11.01A General
72-11.01A(1) Summary
Section 72-11.01 includes general specifications for constructing s lope paving. Construct slope paving using minor concrete or shotcrete. Reinforcement must comply with section 52.
72-11.01A(2) Definitions
Reserved
72-11.01A(3) Submi ttals
Reserved
72-11.01A(4) Quality Assurance
Reserved
72-11.01B Materials
Shotcrete must comply with section 53. The aggregate size used in minor concrete must be from 3/4 to 1 inch. If colored slope paving is described, color the concrete by mixing a fine ground, synthetic mineral oxide into the concrete. The synthetic mineral oxide must be specifically manufactured for coloring concrete. The color of the completed concrete after curi ng and when air dry must match color no. 30450 of AMS - STD-595. Expanded polystyrene and premolded expansion joint filler must comply with section 51 -2.
72-11.01C Construction
72-11.01C(1) General
Construct concrete curbs before constructing sidewalks or slope paving. Concrete curbs must comply with section 73. Mix the coloring agent uniformly and homogeneously with the concrete. Before applying concrete or shotcrete, evenly grade foundations such that no point on the graded slope is above the slope plane shown. Thoroughly compact foundations. Foundations must contain enough moisture to provide a firm foundation and to prevent absorption of water from the concrete or shotcrete. Foundations must be free of surface water. Schedule the construction of th e slope paving such that the work, including placing and finishing concrete or shotcrete and applying curing compound, is completed on the same day that the work is started. If the Engineer determines that the size of the slope paving is too large to be co nstructed without an intermediate construction joint, place a joint at an authorized location. Complete a section of concrete or shotcrete bounded by permissible construction joints within the same day. Cure slope paving by the curing compound method using curing compound no. 6.
72-11.01C(2) Minor Concrete
Construct and finish minor concrete slope paving under section 51 -1. Spread and tamp concrete until it is thoroughly compacted and mortar flushes to the surface. If the slope is too steep to allow the us e of concrete wet enough to flush with tamping, tamp the concrete until it is SECTION 72 SLOPE PROTECTION consolidated and immediately trowel on a mortar surface that is 1/4 inch thick. The mortar must consist of 1 part portland cement or portland limestone cement and 3 parts fine ag gregate. After striking -off to grade, hand -float the concrete with floats that are at least 4 inches wide and 30 inches long. Broom the entire surface with a stiff -bristled broom to produce a uniform surface. Brooming must be done w hen the surface is set enough to prevent deep scarring and must be accomplished by drawing the broom down the slope, leaving marks parallel to the slope. The Engineer may order you to apply a fine spray of water to the surface immediately before brooming.
72-11.01C(3) Shotcrete
Construct and finish shotcrete slope paving under section 53. After the shotcrete has been placed to the depth shown, check the surface with a straightedge. Place additional mortar to bring any low spots or depressions up to the proper grade. The finish of the shotcrete slope paving must be uniform without humps or hollows of more than 1/2 inch in 10 feet.
72-11.01D Payment
The payment quantity for slope paving (concrete) constructed with minor concrete or shotcrete is the product of (1) the area computed from measurements along the slope of the actual areas constructed and
2.the thickness show n for the concrete slope paving. The Department does not pay for additional concrete or shotcrete placed due to overexcavation.
72-11.02 Exposed Aggregate Slope Pa Ving
72-11.02A General
Section 72-11.02 includes specifications for constructing slope paving with an exposed aggregate finish .
72-11.02B Materials
Construct exposed aggregate slope paving using minor concrete. Coarse aggregate must comply with the 1 inch by no. 4 primary size coarse aggregate specified in section 90 -1.02C(4)(b). Concrete set retarders must be commercial -quality and manufactured specifically for use on the top surface of concrete. The r etarder must effectively slow down the setting time of the cement and fine aggregate matrix long enough to permit exposing the aggregates.
72-11.02C Construction
Mix the coloring agent uniformly and homogeneously with the concrete. Place and consolidate t he concrete such that the coarse aggregate remains uniformly distributed throughout the concrete. You may apply a concrete set retarder to the surface of the concrete after placing, consolidating, and finishing of the concrete is complete. Apply the set re tarder under the manufacturer's instructions. When the mass of the concrete is set enough to allow for removing the matrix of cement and fine aggregate, expose the coarse aggregate:
1.With a water spray, coarse brooming, abrasive blasting, or a combinatio n of these procedures. Removal methods must not dislodge or loosen the coarse aggregate from embedment in the mortar.
2.To an approximate depth from 3/16 to 3/8 inch. Exposed aggregate surfaces must be uniform in appearance. Immediately after the cement mortar has hardened enough to resist further removal, clean all cement film and other loose material from the exposed aggregate and all other surfaces with stiff brooms and water. Cure concrete under section 90 -1.03B except when operations for exposing the aggregate are underway. You may use the water curing method. If you remove an area of curing compound during the curing SECTION 72 SLOPE PROTECTION period, keep the area continuously wet until the end of the curing period or until you reapply the curing compound.
72-11.02D Payment
Not Used
72-11.03 Slope Paving With Concrete Pavers
72-11.03A General
72-11.03A(1) Summary
Section 72-11.03 includes specifications for constructing slope paving using concrete pavers.
72-11.03A(2) Definitions
Reserved
72-11.03A(3) Submittals
If using pre-mixed mortar, submit the manufacturer's instructions for the mixing proportions and procedures.
72-11.03A(4) Quality Assurance
Reserved
72-11.03B Materials
72-11.03B(1) General
Reserved
72-11.03B(2) Concrete Pavers
Concrete pavers for slope paving must comply with ASTM C90 for solid units. The surface exposed to view must have a split face texture. The nominal size of the concrete pavers must be 8 by 2 by 16 inches.
72-11.03B(3) Mortar
Cement must comply with section 90 -1.02B(2). Hydrated li me must comply with ASTM C207, Type S. Mortar sand must be commercial quality and free of organic impurities and lumps of clay and shale. Mortar must consist by volume of 1 -part cement, from 0 to 0.5 part hydrated lime, and from 2.25 to 3 parts mortar sand . Add enough water to make a workable mortar. Accurately measure and thoroughly mix each batch of mortar. Do not retemper mortar more than 1 hour after mixing. Reduce the amount of lime as necessary to prevent leaching and efflorescence on the finished sur face. You may use a premixed packaged mortar blend of cement, lime, and sand, without color, that requires only water to prepare for use as mortar. Packages of the premixed mortar must show the manufacture's name, brand, weight, and color identification.
72-11.03B(4) Bond Coat
The bond coat must be either dry -set mortar or latex -portland cement mortar. Organic adhesive must not be used for the bond coat. Mix the bond coat under the manufacturer's instructions. The consistency of the mixture must be such th at ridges formed with the recommended notched trowel do not flow or slump. You may rework the bond coat provided no water or materials are added.
72-11.03B(5) Grout
Grout must be suitable for grouting quarry tile and must comply with ANSI Standard: A 108. 5. Grout must consist, by volume, of 1 part cement, up to 1/5 part lime, 2 parts of sand, and an amount of water to provide a grout with a consistency that can be forcibly compressed into joints. You may use a premixed packaged grout blend of cement, lime, and sand that is suitable for grouting quarry tile and requires only water to prepare for use as brick grout. Packages of the premixed grout must show the manufacturer's name, brand, weight, and color identification. SECTION 72 SLOPE PROTECTION
72-11.03C Construction
72-11.03C(1) General
Joints must be straight and of uniform and equal width. Protect surfaces of completed masonry, concrete, and other materials exposed to view from spillage, splatters, and other deposits of cementitious materials from masonry construction. Remove th ese deposits without damage to the materials or exposed surfaces. Stains, efflorescence, laitance, splashes, or spots on the faces of masonry exposed to view must be removed. Apply cleaning agents under the paver manufacturer's instructions to a sample area determined by the Engineer. Do not continue with cleaning beyond the sample area until the Engineer authorizes the cleaning agent and the cleaning methods.
72-11.03C(2) Installation using a Bond Coat
Install concrete pavers on a bond coat over a mortar bedding. Do not use air blown mortar . Roughen and clean the concrete surfaces against which concrete pavers are to be placed, exposing the stone aggregate. Immediately before placing the paver units, flush the concrete surface with water and allow it to dry to a surface dry condition. Prepare the concrete surfaces to receive a mortar setting bed under the specifications for horizontal construction joints in section 51 -1.03D(4). The mortar setting bed must be at least 1 inch thick and be finished parallel to the finished brick surface. Cure the setting bed for at least 24 hours before placing the bond coat. Roughen and clean the surfaces of the cured setting bed. The surface must be free of laitance, coatings, oil, sand, dust, and loose pa rticles. Dampen the cured setting bed before placing the bond coat. Do not soak the setting bed . Float the bond coat onto the cured setting bed with enough pressure to cover the surface evenly with no bare spots. The surface area to be covered with the bon d coat must be no greater than the area that can be covered with concrete pavers while the bond coat is still plastic. Comb the bond coat mortar with a notched trowel within 10 minutes before installing concrete pavers. Do not install the concrete pavers o n a skinned -over mortar bond coat. Back -butter the concrete pavers immediately before installing the units. Firmly press the concrete pavers into the freshly notched bond coat. Tap the concrete pavers to a true surface to attain 100 percent coverage of the bond coat with the back of each unit. Head and bed mortar joints must be 1/2 inch thick. Remove spacers, strings, ropes, pegs, glue, paper, and face mounting material before grouting the concrete pavers. Do not start g routing until at least 48 hours after installing concrete pavers. Force a maximum amount of grout into the joints between and surrounding the concrete paver units. Tool the grout to a slightly concave cross section to a depth not more than 1/8 inch below the finished surface. The finished gro ut must have a uniform color and must be smooth without voids, pinholes, or low spots. Keep the concrete pavers continuously damp for at least 72 hours after grouting.
72-11.03C(3) Installation on a Mortar Bedding
The top surface of the air -blown mortar o r concrete base must be lightly and evenly scored horizontally and vertically with a metal scratcher having grooves not more than 1 inch apart. Cure the air -blown mortar or concrete base by the water method for at least 2 days. Lay and embed the concrete p avers in approximately 1 -inch thick mortar. Embedment must be shoved tight such that mortar is flushed into the joints to a depth of approximately 1/2 inch. SECTION 72 SLOPE PROTECTION
72-11.03D Payment
Not Used
72-11.04 Slope Paving With Rock Cobble
72-11.04A General
72-11.04A(1) Summary
Section 72-11.04 includes specifications for constructing slope paving using rock cobbles on mortar beds.
72-11.04A(2) Definitions
Reserved
72-11.04A(3) Submittals
Submit 2 samples of the rock cobble at least 15 days before placing the rock cob ble surface of the slope paving. If using premixed mortar, submit the manufacturer's instructions for the mixing proportions and procedures.
72-11.04A(4) Quality Assurance
Reserved
72-11.04B Materials
72-11.04B(1) General
Reserved
72-11.04B(2) Rock Cobble
Rock used for the slope paving with rock cobble must be clean and smooth rock obtained from a single source. Flat or needle shapes must not be used unless the thickness of the individual pieces are greater than 1/3 the length. Rock must be mostly tan, but include a variety of colors including red, rose, brown, gray, and light gray river rock cobble. Rock used for the slope paving with rock cobble must conform to the following gradation: Screen size (in ch) Percentage passing 8 100 6 50–85 4 0–50
72-11.04B(3) Mortar
Mortar must comply with section 72 -11.03B(3).
72-11.04C Construction
72-11.04C(1) General
Protect surfaces of completed rock cobble, concrete, and other materials on the exposed surface from spillage, splatters, and other deposits of cementitious materials from rock cobble construction. Remove these deposits without damage to the materials or exposed surfaces. Stains, efflorescence, laitance, splashes, or spots on the faces of rock cobble exposed to vie w must be removed.
72-11.04C(2) Installation on a Mortar Bedding
The top surface of the shotcrete or concrete base must be lightly and evenly scored horizontally and vertically with a metal scratcher having grooves not more than 1 inch apart. Cure the sho tcrete or concrete base by the water method for at least 2 days before placing rock cobbles. SECTION 72 SLOPE PROTECTION Clean concrete areas to be in contact with mortar of loose or foreign material that would prevent bonding between the mortar and the concrete surfaces. Flush the c oncrete areas with water and allow them to dry to a surface -dry condition immediately before placing mortar. Lay and embed rock cobble in mortar. Rock cobble must be tightly seated so the mortar is flushed into the joints. Excess mortar must be removed. After the rock cobbles have been set in the mortar, exposed top surfaces must be thoroughly cleaned. Unless authorized, the clear distance between placed rock cobbles must not exceed 1-1/2 inches. Loose rocks must be reset. Cure mortar by keeping the surface damp for 3 days.
72-11.04D Payment
Not Used
72-12 72-15 Reserved
72-16 Gabions
72-16.01 General
72-16.01A Summary
Section 72 -16 includes specifications for constructing gabion structures. Gabions consi st of wire mesh baskets that are placed and then filled with rock.
72-16.01B Definitions
Reserved
72-16.01C Submittals
Submit a certificate of compliance for each shipment of gabion baskets to the job site. Submit a certificate of compliance for the PVC coating. Identify any UV -resistance additive on the certificate of compliance.
72-16.01D Quality Assurance
72-16.01D(1) General
Reserved
72-16 01D(2) Quality Control
If ordered, verify the unit weight of a rock -filled gabion. Verify the weight usin g the smallest standard gabion basket, filling method, and rock that will be used on the project. Use certified scales for weighing. Calculate the unit weight using the theoretical volume of the basket.
72-16.02 Materials
72-16.02A General
The standard s izes for gabion baskets must be either of the following:
1.Mattress style that are 12 by 18 by 36 inches
2.Cubical style that are 36 by 36 by 36 inches The width, height, or length of a standard basket must not vary more than 5 percent from the standard size shown. Each gabion must be manufactured with the necessary panels that are properly spaced and secured such that the panels can be rotated into position without additional tying of the rotation joint.
72-16.02B Mesh
Use the same mesh for each style and size of gabion basket. The size of wire used to manufacture mesh must comply with the requirements shown in the following tables: SECTION 72 SLOPE PROTECTION Wire Size with PVC Coating Gabion basket style USA wire gauge Mesh type Cubical 12 Twisted 11–9 Welded Mattress 12 Twisted 11 Welded Wire Size without PVC Coating Gabion basket style USA wire gauge Mesh type Cubical 11 Twisted 11–9 Welded Mattress 11 Twisted 11 Welded Wire must comply with the requirements shown in the following table: Wire Material Requirements Quality characteristic Test method Requirement Tensile strength (min, ksi) ASTM A370 60 12-gauge wire: Diameter (min, in ch) Zinc coating (min, oz/sq ft) ASTM A641/A641M ASTM A641/A641M Class 3 and A90 0.106 0.75 11-gauge wire: Diameter (min, in ch) Zinc coating (min, oz/sq ft) ASTM A641/A641M ASTM A641/A641M Class 3 and A90 0.120 0.80 9-gauge wire: Diameter (min, in ch) Zinc coating (min, oz/sq ft) ASTM A641/A641M ASTM A641/A641M Class 3 and A90 0.144 0.85 Twisted -mesh wire must be formed with a nonraveling twist and into a uniform hexagonal pattern. For PVC-coated wire, use 10 -gauge size for the selvage wires. For wire without a PVC coating, use 9 -gauge size for the selvage wires. Welded -mesh wires must:
1.Be formed into the grid pattern shown
2.Be welded by resistance welding
3.Comply with ASTM A1084 except weld shears must be: 3.1. 600 lb minimum for 11 -gauge wire 3.2. 800 lb minimum for 9 -gauge wire Resistance welding after coating the wire with zinc is allowed if there are no large splashes, flakes, or flashes of zinc at the weld.
72-16.02C PVC Coating
If PVC coating is shown, coat the mesh wire, standard tie wires, standard binders, internal connecting wires, preformed stiffeners, and selvage wire. A PVC coating must be UV resistant. A suitable UV -resistance additive must be blended with the PVC. If the gabions are exposed to natural sunlight, the color of the PVC coating must be gray and resistant to fading. Apply the zinc coating before applying the PVC coating. Application of the PVC coating must comply with the manufacturer's instructions. SECTION 72 SLOPE PROTECTION Evaluate the PVC coating by infrared spectral scan. The scan must closely match those of tested and accepted materials already on file at METS . The m inimum thickness of the PVC coating must be 0.015 inch when measured radially at any cross - section transverse to the wire length. PVC coating will be visually inspected. There must be no nicks, cuts, holidays, or abraded areas. Minor cuts, nicks, and other minor imperfections due to manufacturing are allowed along the selvage -wrapped edges of the twisted wire mesh. You are not required to coat the ends of the wires where they have been trimmed along wire or panel edges during the normal manufacturing proces ses.
72-16.02D Joints
Standard tie wire and standard spiral binder wire must comply with the requirements shown in the following table. Tie Wire and Spiral Binder Wire Material Requirements Quality characteristic Test method Requirement Tensile strength (min, ksi) ASTM A370 60 Tie wire 13.5-gauge wire : Diameter (max, in ch) Diameter (min, in ch) Zinc coating (min, oz/sq ft) ASTM A641/A641M ASTM A641/A641M A641/A641M Class 3 and ASTM A90 0.086 0.082 0.70 Spiral binder wire 9-gauge wire : Diameter (max, in ch) Diameter (min, in ch) Zinc coating (min, oz/sq ft) ASTM A641/A641M ASTM A641/A641M ASTM A641/A641M Class 3 and ASTM A90 0.148 0.144 0.85 Spiral binders must have a 3 -inch separation between continuous successive loops. If shown, you may use alternative fasteners. For PVC -coated wire, alternative fasteners must comply with ASTM A313/A313M, tensile Type 302, Class 1. For wire without PVC coating, alternative fasteners must comply with ASTM A764 and:
1.Interlocking fasteners must be Class I, Finish 2 with a Class 3 zinc finish coating
2.Overlapping fasteners must comply with Class II, Finish 1 with a Class 3 zinc finish coating
72-16.02E Internal Connecting Wire
Internal connecting wires must be a minimum size of 13.5 -gauge . The wire must comply with the specifications for tie wire in section 72 -16.02D. You may use preformed stiffeners instead of internal connecting wires. Preformed stiffeners must comply with the specifications for tie wire in section 72 -16.02D and be insta lled under the manufacturer's instructions.
72-16.02F Fabric
If gabions are shown for downdrains , use woven tape fabric. Woven tape fabric must comply with ASTM D4491, have a mass of at least 8 oz/sq yd, and have a maximum permeability of 7.5 gal/minute/s q ft.
72-16.02G Rock
Rock for filling gabions must comply with the testing and corresponding specifications in section 72 - 2.02B. SECTION 72 SLOPE PROTECTION Rocks for gabion baskets equal to or greater than 18 inches in height must vary in size and comply with the gradation requirements shown in the following table: Rock Gradation for 18 -Inch or Larger Baskets Screen size (in ch) Percentage passing 12 100 4 0–5 Rocks for gabion baskets that are 12 inches in height must vary in size and comply with the gradation requirements shown in the following table. Rock Gradation for 12 -Inch Baskets Screen size (in ch) Percentage passing 8 100 4 0–5 The unit weight of a rock -filled gabion must be at least 110 lb/ cu ft.
72-16.03 Construction
72-16.03A General
Areas where gabions are to be placed must be constructed to the lines and grades shown. If fabric is shown, place the fabric on the subgrade, backslope, and sides of the excavations. If earth fill is to be placed over the gabions, place the fabric on top of the gabions before placing the earth fill. Gabions must be divided by diaphragm panels such that baskets are 36 -inch-long cells.
72-16.03B Assembly
Individually assemble e mpty gabion baskets and successively join the baskets . Assemble t he individual mesh panels, base, front, ends, back, diaphragms, and lid, and successive gabions such that the strength and flexibility along the joints is comparable to a single panel. Assemble the gabions as empty units. Rotate panels and diaphragms into position and join them along the vertical edges. For twisted wire mesh, construct joints using alternatin g double and single half hitches and locked loops made at 4 -inch nominal spacing. Use 13.5 -gauge standard tie wire. Do not constru ct joints with simple spiraling or looping without locking, of the tie wire. For welded wire mesh, construct joints using eith er of the following:
1.Standard tie wire and alternating double and single half hitches and locked loops, in every mesh opening along the joint .
2.9-gauge spiral binders with the spiral binder passing through every mesh opening along the joint. Crimp bot h ends of the spiral binder and secure it in place . You may use temporary fasteners to hold panels at gabion -to-gabion joints. The temporary fasteners may remain in place. Use either interlocking fasteners or overlapping fasteners. Place a fastener at eac h mesh opening along the joint. For PVC coated wire, the spacing of fasteners must be at least 10 fasteners per 36 inches. For wire without PVC coating, the spacing of fasteners must be at least 10 fasteners per 40 inches. Set individual gabion baskets in place. Successively join the basket to the adjacent basket with 13.5 - gauge tie wire or 9 -gauge standard spiral binder before filling the basket with rock. In 1 pass, the tie wire or spiral binder must secure all selvage or end wires of the panels along the joint. If forming successive gabion -to-gabion joints with alternative fasteners, use 1 alternative fastener at each mesh opening. The alternative fastener must contain and secure all wires along the joint. SECTION 72 SLOPE PROTECTION Join gabion baskets along the front, back, and en ds, including the top and bottom of adjacent gabions. Step and stagger m ulti-layered gabion configurations . Join each layer of gabion to the underlying layer along the front, back, and ends. Join shear key and counterfort gabions to the underlying gabions along the front, back, and ends. For transitional gabions, fold, cut, and fasten the gabion baskets as shown or as a uthorized .
72-16.03C Filling
Before filling each gabion basket, straighten any kinks and folds in the wire and align the baskets. Place roc k in the basket and preserve the alignment. Avoid bulges and minimize voids. Exposed rock surfaces must have a smooth and neat appearance. Sharp rocks must not project through the wire mesh. Use internal connecting wires or preformed stiffeners to produce a flat, smooth external surface. When filling 36 -inch-high gabions, place the rock in 12 -inch-deep layers. When filling 18 -inch-high gabions, place the rock in 9 -inch-deep layers. Install internal connecting wires or preformed stiffeners before adding addi tional layers. The last layer of rock must slightly overfill the gabion basket such that the lid will rest on rock when the lid is closed. Lids must be tied along the front, end, and diaphragms with 13.5 -gauge tie wire or 9 -gauge standard spiral binder. In 1 pass, the tie wire or spiral binder must secure all selvage or end wires of the panels along the lid. If securing the lid with alternative fasteners, use 1 alternative fastener at each mesh opening. The alternative fastener must contain and secure all w ires along the lid.
72-16.04 Payment
The payment quantity for gabion is the volume determined from the dimensions shown or the actual volume of gabions placed .
72-17 Existing Slope Protection
72-17.01 General
72-17.01A General
Section 72 -17 includes specifications for performing work on existing slope protection.
72-17.01B Materials
Not Used
72-17.01C Construction
Not Used
72-17.01D Payment
Not Used
72-17.02 Remove Slope Paving
72-17.02A General
Section 72-17.02 includes sp ecifications for removing slope protection.
72-17.02B Materials
Not Used
72-17.02C Construction
Not Used SECTION 72 SLOPE PROTECTION
72-17.02D Payment
The payment quantity for remove slope paving is the area of the slope paving measured before starting removal
72-18 72-25 Reserved
Source: California Standard Specifications, 2024 Edition. Pages 1035–1052 of 1,372.