ITEM 512 – EROSION CONTROL MATS, ROVING, AND CELLULAR CONFINEMENT SYSTEMS
512. Description
This item shall consist of furnishing and placing erosion control mats,
roving and cellular confinement systems installed at the locations
designated for ditch and slow protection, and stabilization, in accordance
with this specification and in conformity with the lines, grades,
dimensions, and arrangements shown on the Plans or as directed by the
Engineer .
512.2 Material Requirements
512.2.1 Erosion Control Mats
Erosion control mats shall conform to the specifications as shown below:
512.2.1.1 Type 1
- Straw mats, burlap fabric, jute mesh, and woven paper or sisal mesh
netting
1. Straw mats - shall be clean agricultural straw made from oats, wheat,
rye, or other grain crops that is free from weeds, mold, or other
objectionable material and furnished in an air-dry condition suitable for
placing with mulch blower equipment. Straw erosion control mat shall
conform to Table 1 as shown below:
Table 1 - Straw Erosion Control Mat
Material
|
Property
|
Specification
|
Straw(1)
Netting
|
Moisture Content, g/m2, min.
Photodegradable netting on one side 5 - 20 mm square mesh (2), kg/100 m2 min.
|
240
1.5
|
(1) Moisture content shall not exceed 20 percent
(2) Dimensions are approximate and may vary to meet manufacturer's
standards.
2. Burlap fabric - ·shall have a standard weave and a mass of 145
±20 grams per square meter.
3. Jute mesh - shall have a uniform open plain weave fabricated from jute
yarn that does not vary in thickness by more than half its normal diameter.
Jute mesh shall conform to the following:
Mesh size 25 by 25 mm max.
Mesh mass, ASTM D 1776 0.5 kg/m2 ± 5%
4. Woven paper or sisal mesh petting - Mesh netting ' of woven paper or
woven sisal twisted yarn conforming to the following:
Mesh openings 3 to 6 mm
Shrinkage after wetting 20% max.
512.2.1.2 Type 2
- Straw and coconut mats, excelsior blanket, or mulch blanket
1. Straw and coconut mats - a mat consisting of straw and undyed untreated
biodegradable jute, coconut coir, and synthetic polypropylene fibers or
other approved yarn woven into a plain weave mesh. Straw and coconut mats
shall conform to Table 2 as shown below:
Table 2 - Straw and Coconut Mat
Material
|
Property
|
Specification
|
Straw(1) 70%
Coconut 30%
Netting
|
Moisture Content, g/m2, min.
Moisture Content, g/m2, min. Photodegradable netting on both sides 16 - 25 mm square mesh(2), kg/100 m2 min. |
240
240
1.5
|
(1) Moisture content shall not exceed 20 percent
(2) Dimensions are approximate and may vary to meet manufacturer's
standards
2. Excelsior blanket - shall be of uniform thickness consisting of curled
wood excelsior secured on the top side to a biodegradable, photodegradable
extruded plastic mesh and shall be smolder resistant without the use of
chemical additives. Excelsior blanket shall conform to the following:
Excelsior fibers > 200 mm length 80% min.
Mesh size 25mm by 50mm
Blanket mass/area 0.53±0.05 kg/m2
3. Mulch blanket - shall be 3 to 13 mm thick blanket consisting of organic,
biodegradable mulch such as straw, curled wood cellulose, coconut coir, or
other material evenly distributed on one side of a photodegradable,
polypropylene mesh having a minimum mass of 0.27 kg/m2.
512.2.1.3 Type 3
- Coconut mat
Coconut mat - shall consist of undyed untreated biodegradable jute, coconut
coir, and synthetic polypropylene fibers or other approved yarn woven into
a plain weave mesh with approximately 16 to 25 mm2 openings.
Coconut mat shall conform to Table 3 as shown below:
Table 3 - Coconut Mat
| Material | Property | Specification |
| Coconut(1) 100%
Netting |
Moisture Content, g/m2, min.
Photodegradable netting on one side 16 - 25 mm square mesh (2), kg/100 m2 min. |
240
1.5 |
(1) Moisture content shall not exceed 20 percent
(2) Dimensions are approximate and may vary to meet manufacturer's
standards.
512.2.1.4 Type 4
- Synthetic erosion control mats and meshes
1. Synthetic mat -· Flexible · mat produced by machine, consisting of
polyolefin monofilament fibers positioned between 2 biaxially oriented
nets. Mechanically bind the nets together by parallel stitching with
polyolefin thread to form a 3-dirriensional web-like weave, highly
resistant to environmental and chemical deterioration. Synthetic mat shall
conform to Table 4 as shown below:
Table 4 - Synthetic Erosion Control Mat
Property
|
Specifications
|
Test Method
|
| Color
Thickness, mm, min. Strength (1), N/m min. Elongation (1), %, max. Porosity (2) Resiliency (3), %, min. Ultraviolet stability (4), % |
Green
6
1590 x 525
50
85
80
80
|
Visual
ASTM D 1777
ASTM D 5035
ASTM D 5035
Calculated
ASTM D 1777
ASTM D 4355
|
(1) Values for both, machine and· cross-machine directions under dry or
saturated conditions. Machine direction specimen for 50 mm strip test
includes one machine direction polyolefin stitch line centered within its
width and extending the full width length of the specimen.
(2) Calculation based upon mass, thickness, and specific gravity.
(3) The percentage of original thickness retained after 3 cycles of a 690
kilopascal load for 60 seconds followed by 60 seconds without load. Thick
measured 30 minutes after load removed.
(4) Tensile strength retained after 1000 hours in a Xenon ARC
weatherometer.
2. Synthetic polypropylene mesh - A flexible woven geotextile mesh
fabricated from polypropylene fibers that were spun in one direction.
Synthetic polypropylene mesh shall conform to Table 5 as shown below:
Table 5 - Synthetic Polypropylene Mesh
Property
|
Specifications
|
Test Methods
|
| Color
Mass, g/m2, min. Tensile Strength, N/m, min. Elongation at break, %, max. Mullen burst strength, kPa, min. |
Beige
59
6700 X 3700
40
515
|
Visual
ASTM D 5261
ASTM D 5035
ASTM D 5035
ASTM D 3786
|
3. Synthetic mulch control netting - A uniformly extruded rectangular,
plastic mesh netting with 50 by 50 mm nominal mesh openings and weighing at
least 8 grams per square meter.
4. Organic mulch control netting - A leno weave mesh netting fabricated
from 12. 7 kg biodegradable cellulose fiber yarn having 5 twists per 25 mm.
Make the size of the mesh grid 13 to 25 mm2. Finish the selvedge
to prevent raveling or fraying.
512.2.1.5 Type 5
- Turf reinforcement mats
Turf reinforcement mats - A web of mechanically or melt bonded polymer
netting, monofilaments, or fibers that are entangled to form a strong and
dimensionally stable mat. Bonding methods include polymer welding, thermal
or polymer fusion, or the placement of fibers between 2 high-strength,
biaxially oriented nets mechanically bound together by parallel stitching
with polyolefin thread and is resistant to biological chemical, and
ultraviolet degradation. Turf reinforcement mats shall conform to Table 6
as shown below:
Table 6 -Synthetic Polypropylene Erosion Control Mat
| Property | Specification | Test Method |
| Color
Thickness, mm, 1min. Tensile Strength (1), N/m, max. Elongation (1), %, max. Porosity (2), %, max. Resiliency (3), %, min. Ultraviolet stability (4), %, min. Functional Longevity |
Black
13
1370 X 790
50
90
80
80
5 years
|
Visual
ASTM D 1777
ASTM D 5035
ASTM D 5035
Calculated
ASTM D 1777
ASTM D 4355
Observed
|
(1) Values for both machine and cross-machine directions under dry or
saturated conditions using 50 mm strip method.
(2) Calculation based upon mass, thickness, and specific gravity.
(3) The percentage of original thickness retained after 3 cycles of a 690
kilopascal load for 60 seconds followed by 60 seconds without load.
Thickness measured 30 minutes after load removed.
(4) Tensile strength retained after 1000 hours in a Xenon ARC
weatherometer.
512.2.2 Emulsified Asphalt
Emulsified asphalt shall conform to the applicable requirements of Item
304, Bituminous Surface Treatment.
512.2.3 Cellular Confinement Systems
A flexible honeycomb 3-dimensional structure fabricated from polyethylene
that has been properly stabilized with carbon black and/or hindered amine
light stabilizers.
512.2.4 Roving
Types of Roving
1. Fiber glass roving -Fiber glass roving shall be formed from continuous
fibers drawn from molten glass, coated with a chrome-complex sizing
compound, collected into strands and lightly bound together into roving
without the use-of clay, starch, or like deleterious substances. Roving
shall be wind into a cylindrical package approximately 300 mm high so it
can be continuously fed from the center of the package through an ejector
driven by compressed air and expanded into a mat of glass fibers on the
soil surface. Roving containing petroleum solvents or other agents known to
be toxic to plant or animal life shall not be used. Fiber glass roving
shall conform to the following:
Strands/rove, end count 56 to 64
Fibers/strand, end count 184 to 234
Fiber diameter (trade designation G), ASTM D 578 0.009 to 0.013 mm
m/kg of rove, ASTM D 578 340 to 600 m/kg
km/kg of strand, ASTM D 578 26.2 to 2.82
Organic content, ASTM D 578 1.65% max.
2. Polypropylene roving - Polypropylene roving shall be formed from
continuous strands of fibrillated polypropylene yarn. Roving shall be
winded into a cylindrical package so that it can be continuously fed from
the outside of the package through an ejector driven by compressed air and
expanded into a mat of polypropylene strands. The material shall not
contain agents that are toxic to plant or animal life. Polypropylene roving
shall conform to the following:
Tensile strength, ASTM D 2256 15.6 N
Elongation at break, ASTM D 2256 15.5%
Mass of strand, ASTM D 1907 360 denier
Strands per rove, measured 24
UV stability, ASTM D 4355 50% retained after 200 hours
512.2.5 Topsoil
Topsoil shall conform to the requirements of Item 608, Topsoil, of the DPWH
Standard Specifications, Volume II.
512.2.6 Turf Establishment
1. Agricultural limestone
Agricultural limestone shall conform to the requirements of Item 609,
Subsection 609.2.3, Ground Limestone, of the DPWH Standard Specifications,
Volume II.
2. Fertilizers
Fertilizers shall conform to the requirements of Item 609. Subsection
609.2.2, Fertilizers, of the DPWH Standard Specifications Volume II.
3. Mulch
Straw -shall be made from oats, wheat, rye, or other grain crops that is
free from weeds, mold, or other objectionable ·material and in an air-dry
condition suitable for placing with mulch blower equipment.
Hay -shall be made from herbaceous mowing, free from weeds, mold, or other
objectionable material. Furnish hay in an air-dry condition suitable for
placing with mulch blower equipment.
Wood fiber -shall be processed from wood chips that is as follows:
a. Colored with a green dye non-injurious to plant growth
b. Readily dispersible in water
c. Nontoxic to seed or other plant material
d. Free of growth or germination inhibiting substances
e. Free of weed seed
f. Air dried to an equilibrium moisture content of 12±3 percent
g. Packaged in new labeled containers
h. Packaged in a cond1t1on appropriate for mixing in a homogeneous slurry
suitable for application with power spray equipment
Grass straw cellulose fiber -shall be processed from grass straw fiber that
is as follows:
a. Colored with a green dye non-injurious to plant growth
b. Readily dispersible in water
c. Nontoxic to seed or other plant material
d. Free of growth or germination inhibiting substances
e. Free of weed seed
f. Air dried to a moisture content of 10+0.2 percent.
g. Air dried to a uniform mass of 15 percent
h. Packaged in new containers labeled with the manufacturer's name and
air-dry mass
i. Packaged in a condition appropriate for mixing in a homogeneous slurry
suitable for application with power spray equipment.
Peat moss -shall be a granulated sphagnum peat moss conforming to the
following:
Sticks, stones, and mineral matter 0%
Partially decomposed stems and leaves of sphagnum 75% min.
Color brown
Textured from porous fibrous to spongy fibrous
pH 3.5 to 7.5
Air-dried
Mature compost - shall be a partially decomposed organic material, such as
leaves, grass, shrubs, and yard trimmings, cured for 4 to 8 weeks. Maturity
is indicated by temperature stability and soil-like odor. Also shall be
friable, dark brown, weed-free, and pathogen-free mature compost conforming
to the following:
Carbon/nitrogen ratio 25/1 to 35/1
Carbon/phosphorus ratio 120/1 to 240/1
pH 6.0 to 7.8
Water content 40% max.
Particle size
Seeding and sodding 12 mm max.
Erosion control 25 mm max.
Organic material 50% min.
Man-made inserts (plastic, glass, metal) 2% max.
Straw for hydroseeding - shall be clean agricultural straw milled to 25 mm
or less in length. Dry the fibers to 10% moisture for compaction. Bale in
heat-sealed plastic bags.
Bonded fiber matrix hydromulch - shall be a mixture of long-wood fibers and
bonding agent which when hydraulically applied and dried produce a matrix
conforming to the following:
a. Does not dissolve or disperse when wetted.
b. Holds.at least 1000 grams of water per 100 grams of drymatrix.
c. Has no germination or growth inhibiting factors.
d. Forms no water insensitive crust.
e. Contains material that is 100 percent biodegradable.
512.3 Construction Requirements
512.3.1 Erosion Control Mats (Type 1, 2, 3, 4, and 5)
Install erosion control mats according to the manufacturer’s
recommendations.
Install erosion control mats to soil surfaces which are at final grade,
stable, firm, and free of rocks or other obstructions. Spread erosion
control mats evenly and smoothly, without stretching, to ensure direct
contact with the soil at all points. Unroll erosion control mats parallel
to the drainage flow direction. Lap edges as recommended by the
manufacturer. Place the upslope end in a 150 mm vertical slot. Backfill the
slot and compact.
For swale or ditch installations, place up the side slopes to extend above
anticipated flow line and construct intermediate 150 mm vertical check
slots at 8 m intervals. Construct check slots perpendicular to flow
direction. Staple erosion control mats as recommended by manufacturer.
Drive all staples flush with the soil surface.
Repair damaged areas immediately. Restore the soil in damaged areas to
finished grade, refertilize, and reseed.
Synthetic erosion control mats and meshes (Type 4) shall be installed after
turf establishment is in place.
Turf establishment mats (Type 5) shall be installed before turf
establishment is in place. After seeding, lightly brush or rake 15±5 mm of
topsoil into the mat voids to fill the mat thickness.
512.3.2 Roving
Furnish a pneumatic ejector capable of applying roving at a rate of 0.9
kilograms per minute. Furnish an air compressor capable of supplying 1.1
cubic meters per minute at 620±70 kilopascals, complete with air hoses
necessary for supplying air to areas not accessible to the compressor.
Furnish an asphalt distributor with necessary hoses and a hand spray bar
for slopes and other areas not accessible to the distributor.
512.3.2.1 Fiber Glass Roving
Spread fiber glass roving uniformly at the rate of 0.16±0.03 kg/m 2 to form a random mat of continuous glass fibers.
512.3.2.2 Polypropylene Roving
Spread polypropylene roving uniformly at the rate of 0.08±0.03 kg/m 2 to form a random mat of continuous polypropylene fibers.
Anchor the roving to the ground with a slow setting emulsified asphalt
applied uniformly at a rate of 1.5±0.2 liters per square meter over the
roving. Bury upslope end of the roving 300 mm deep.
512.3.3 Cellular Confinement Systems
Excavate to the depth of the cellular confinement systems, and smooth and
compact the slope. Install the top of the, system flush or lower than the
adjacent slope. Expand the cellular confinement systems down the slope.
Connect adjacent cellular confinement systems sections with hog rings or
staples every other cell.
Anchor the system with stakes across the top at every other cell. Repeat
the anchoring pattern in every tenth row and in the bottom row.
Backfill the system with topsoil. Hand-compact the topsoil within each
cell. Apply permanent turf establishment.
512.4 Acceptance Requirements
512.4.1 Certification
The manufacturer shall file with the purchaser a certificate stating the
name of the manufacturer, the chemical composition of the filaments or
yarns, and other pertinent information so as to fully describe material
(including mats, roving and other cellular confinement systems) for erosion
control, ditch and slope protection, and stabilization. The manufacturer
shall include in the certificate a guarantee stating that the material that
is furnished meets the requirements of the specification. The certificate
shall be attested to by a person having legal authority bind the company.
Either mismarking or misinterpretation by the manufacturer shall be reason
to discontinue acceptance under these specifications. Notice sent to the
manufacturer by the purchaser regarding the discontinuance of acceptance
will be considered to be notice to all wholesalers, jobbers, distributors,
agents and other intermediaries handling the manufacturer's product.
512.4.2
The Engineer shall evaluate acceptance for the material for topsoil through
visual inspection and comply with the requirements of Item 608, Topsoil.
512.4.3
The Engineer shall evaluate acceptance for turf establishment work through
visual inspection and certification as prescribed in Subsection 512.4.1,
Certification.
512.5 Quality Control
The manufacturer of the material is responsible for establishing and
maintaining a quality control program so as to assure compliance with the
requirements of this specification.
512.6 Shipment and Storage
512.6.1
During periods of shipment and storage, the material shall be protected
from direct sunlight, ultraviolet rays, temperatures greater than 60°C,
mud, dust, and debris. To the extent possible, the material shall be
maintained wrapped in a heavy-duty protective covering. Each shipping
document shall include a notation certifying that the material is in
accordance with the manufacturer's certificate and guaranteed previously
filed with the purchaser.
512.6.2 Product Marking
Label the material and its container with the manufacturer's name,
material's type or trade name, lot number and quantity.
512. 7 Method of Measurement
512.7.1
Erosion control mats, roving, and cellular confinement systems shaII be
measured by the number of square meters excluding overlaps.
512.7.2
Topsoil will be measured and paid for as provided in Item 608, Topsoil.
512.7.3
Turf establishment will be measured on the following applicable methods:
512.7.3.1
Seeding and mulching will be measured by the number of square meters.
512.7.3.2
Fertilizer, dry method will be measured by the metric tonne.
512.2 Basis of Payment
The quantities determined as provided above shall be paid for at the
contract price per unit of measurement, respectively, for each pay Item
listed below.
Payment shall be made under:
Pay Item Number
|
Description
|
Unit of
Measurement
|
| 512 (1)
512 (2) 512 (3) |
Erosion Control Mat Type_
Roving Cellular Confinement Systems |
Square Meter
Square Meter Square Meter |
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