specification sheet - Building Better Cities

SPECIFICATION SHEET
SPECIFICATION SHEET
CONCRETE
PERVIOUS CONCRETE
GENERAL
The following Technical Specification Sheet has been provided by Lafarge for use by the
design community. Information contained in this document may be used as a reference in detailed
drawings or in specification documents.
SUMMARY
Includes: Pervious concrete for Hydromedia® applications
QUALITY ASSURANCE
A pre-job conference will be held at the jobsite to discuss site related points. Those present shall
include the concrete producer, the contractor, the engineer, the architect, and the testing agency. No
concrete placement of Hydromedia concrete will be allowed prior to this meeting.
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AMERICAN AND EUROPEAN STANDARDS
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The above list should not be necessarily considered complete.
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PRODUCT SPECIFICATION
The following chapter lists the raw materials used to manufacture Hydromedia and the
product’s physical-chemical characteristics.
MATERIAL SPECIFICATION
Cement: ASTM C150/ EN 197
Supplementary Cementing Materials: ASTM C898, ASTM C618/ EN 450, EN13263
Coarse Aggregate: ASTM C33-01/EN 12620;
Admixtures: ASTM C494-92/ EN 934-2
Water: ASTM C94/EN 1008
CONCRETE MIX DESIGN
Pervious Concrete: Hydromedia by Lafarge; proprietary ready-mix concrete with the following
characteristics:
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Maximum water cementious ratio: The maximum water cementious ratio is specified by the
Designer Project Engineer.
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Porosity: 20 to 35%
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Permeability: 150 to 1000 L/min/m2
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Compressive Strength at 28 days: 10 MPa to 20 MPa (1450 psi to 2176 psi)
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Flexural Strength at 28 days: 1.5 MPa to 3 MPa (217 psi to 435 psi)
Note: Hydromedia characteristics will depend on the aggregates and on local mix design and
standards.
SPECIFICATION SHEET
EXECUTION
Concrete characteristics are strongly linked to how it is installed. The following chapter
describes how to properly install Hydromedia from the base preparation to the cares that shall be
taken during finishing and curing to assure the quality of the product.
SITE INSPECTION
Verification of Conditions: Examine areas and conditions under which work is to be performed and
identify conditions detrimental to proper or timely completion.
Do not proceed until unsatisfactory conditions have been corrected.
SITE PREPARATION
Coordination: Notify others involved, allowing installation and completion of their work prior to
concrete placement.
Choice of system: The design of pervious concrete systems with Hydromedia will depend on the use
of the surface and the design requirements of a project. Three typical systems to help manage run-off
are described below:
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System A is a permeable system that allows water to infiltrate the soil. It can be used to
replenish ground water. This system is not recommended in locations with high pollution risks.
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System B represents a semi-permeable system, in other words, the quantity of stored water is
limited by the nature of the soil. Excess water is drained to a drainage pipe.
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System C acts as temporary storage, like a reservoir with limited volume, because the soil is
impermeable. Excess water is drained to a drainage pipe.
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Potential systems using Hydromedia
Surface Preparation:
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Hydromedia will be laid over a base of aggregates.
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Use single sized aggregates with no fines to obtain porosity between 30% and 40%,
giving the base the capacity of draining and storing water.
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Use round or crushed aggregates. Crushed aggregates will give a better flatness.
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Ensure a good compaction of the base layers standard devices. Compact sub-grade to 92% of
modified proctor. Compact aggregate base to 95% of modified proctor. A low compaction of
the base layers can change the compaction of the Hydromedia layer. However, do not over
compact, the sub-grade must remain permeable.
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Use crushed aggregates where applicable. Aggregate type can play on the stiffness of the
base layers.
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Pre-wet the base layers prior to pouring Hydromedia. If the base layers are too dry, it may
induce a rapid drying of Hydromedia
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INSTALLATION REFERENCES
Concrete Mixing: ACI 301/ EN 1992-1-1, ready mixed.
Hot Weather Concrete: Comply with ACI 305R when maximum daily temperature exceeds 30°C
(86°F) or rapid drying conditions exist.
Cold Weather Concrete: Comply with ACI 306R when freezing conditions or a mean daily
temperature below 5°C (41°F) is encountered.
CONCRETE PLACEMENT AND CONSOLIDATION
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Usually pervious concrete placement is completed by hand, using forms (mainly wood + raiser
strip).
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Concrete placement can be done by either direct discharge or using concrete conveyers.
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Pumping is not recommended.
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Vibrating screeds or standard screeds and roller compacters can be used for strike off.
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Telebelt or conveyer is one of the most effective methods, it can transport the concrete
distances in excess of 30.5 m (100 ft).
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If conditions allow, buggies can also be used to place it. However, the concrete will be
exposed for a longer time and Hydromedia has a rapid rate of drying when exposed to the
environment.
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If the concrete is placed in long, narrow strips, then it can be placed off the ready mix truck.
The chute should be well adjusted to assure a good discharge of the concrete.
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Try to pick a day and time that minimizes wind exposure and high temperatures.
FINISHING METHODS
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Finishing for Hydromedia is similar to standard pervious concrete.
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A low level of compaction is expected, thus using riser strips may result in an uneven and noncompactable surface.
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A roller is an effective way to compact Hydromedia.
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The roller should weigh approximately 30 Kg (70 lbs).
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The surface is then fixed manually with a trowel.
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This method is particularly effective if there is no strength requirement for the concrete.
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A low compaction is obtained.
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A Hydraulic Roller can also be used. This method gives a good compaction and it levels and
screeds at the same time. However Hydromedia may stick to the roller and it can “tear” the
surface.
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A Paving machine gives good results for big areas. It’s easy and fast to use, but not all pavers
are sufficient and the use of one should be discussed with your Lafarge representative. It
should only be used if the base is made of crushed aggregates.
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A Plate tamper is the recommended finishing method. It is suggested that plywood be used
beneath the tamper to protect the surface from exposure and to obtain a flat surface. It
SPECIFICATION SHEET
minimizes the surface exposure and results in a good finish with good compaction. The
procedure is described below:
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Use a conveyor belt if possible, otherwise keep in mind that Hydromedia is similar to a
100 to 150 mm (4 to 6 in) slump concrete and the angle of the truck chute should be
sufficient to allow the material to flow.
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Use a rake or shovel to place the concrete as evenly as possible.
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Level and screed the surface to the desired height. Using a roller screed is ideal
because it adds a small amount of compaction while it screeds and levels. Do this in
one pass if possible.
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Cover the levelled surface with a large plastic sheet at the same moment the surface is
levelled and screeded to avoid drying.
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As soon as a section is complete and all covered with plastic, return to the beginning of
the slab, remove a portion of the sheet.
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Place the plank on the surface and the vibrating compactor on the top of the plank.
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Vibrate and compact the pavement by using the plank to evenly distribute the
compaction and vibration. Try not to pass over the same area repeatedly.
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Lastly, immediately cover the surface with a plastic sheet as the plank is removed and
the vibrating compactor finishes an area. Ensure that the plastic sheet is secured along
the perimeter.
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A non-level surface could be caused by the gap between plywoods. The use of a hand
tamper has shown to be a good solution to correct it.
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Constantly going over the area with either the roller screed or vibrating compactor will increase
ravelling in the final product.
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Be sure that the Hydromedia pavement is covered and sealed well upon completion.
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Minimize walking or placing weights above 20 Kg (44 lbs) on the surface after the Hydromedia
pavement has been finished.
JOINTS
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Joints are recommended for construction or aesthetics reasons.
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Minimize joints where possible. Ravelling tends to occur at the joints.
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ACI 522 recommends jointing for standard Pervious. These rules can apply to Hydromedia:
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Distance between joints should be less than 6 m.
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It is recommended to make the joints during the fresh state of Hydromedia, soon after
finishing the surface.
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Joint cutters are recommended for Hydromedia during the fresh state.
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Saw cuts are also possible. Keep in mind that small particles are produced with this
method. Try to minimize the amount of particles clogging the Hydromedia pavement.
Random cracks that do form are not abundant and they have no significant impact on the
structural integrity of the pavement. They also generally do not detract aesthetically from the
concrete appearance.
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Typical joint pattern according to ACI 522
CONCRETE CURING AND PROTECTION
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If possible, curing should be completed immediately after the concrete has been discharged
from the back of the truck. The maximum amount of time the surface should be exposed to the
air is 20 minutes.
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Minimize the surface exposure by covering the surface with plastic when possible.
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Minimize walking or disturbing the surface after finishing.
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It is recommended that 0.15 mm (5.9 mil) plastic sheet be applied on the surface for curing
and placed flat on the surface within 20 min. Secure the plastic sheet along the pour perimeter
avoiding any wind from blowing in between the sheet and concrete surface.
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Burlap or geotextile fabric are not sufficient curing membranes because they do not hold the
moisture in the concrete.
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Current wax-based curing agents should be avoided.
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The plastic should remain on the concrete for 7 days with Portland cement mixes and 10 days
with blended cement mix.
MAINTENANCE
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Maintenance is required when the clogging indicator (CI) is below 50%
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Record infiltration rate after concrete has completed the curing phase.
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Perform clogging indicator testing every 6 months or when clogging is in question.
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Clogging indicator ratio is CI/CIinitial*100.
SPECIFICATION SHEET
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Street sweepers with vacuum and brushes are an effective way of cleaning the voids in the
pavement and, therefore, restore permeability.
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High pressure hosing can also be applied after the pavement has been swept and vacuumed
thoroughly.
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Pressure washing is also effective, however it is more expensive.
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Hard surface cleaning can also be used and it gives better results than pressure washing.
FIELD QUALITY CONTROL
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Strength Tests: EN 12390/ ASTM C39
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Subjective test: Visually analyze Hydromedia:
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If Hydromedia mix is well adjusted:
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All aggregates are well coated.
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The paste gives a sheen on the aggregate.
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Wearing a latex glove, form a ball of concrete in your hand (ball hand test).
Upon release the concrete will fall apart. After releasing the concrete, a small
quantity of paste will stick to the glove if the aggregates were well-coated.
If Hydromedia is too dry:
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Concrete looks stiff and a ball can be made in the ball hand test.
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Aggregates do not look coated.
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Paste does not have a sheen.
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The problem is caused by a lack of water or SP (super-plasticizer).
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It is safer to increase the SP content to solve the problem, because water
content affects segregation. Be aware that very high quantity of SP will also
cause segregation.
If Hydromedia is too wet:
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The paste remains in the bottom of the mix.
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When performing the ball test the concrete will fall apart more of the aggregate
structure can be seen. None of the aggregates remains in the hand and bigger
spots of paste are seen.
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The problem is caused by an excess of water or SP.
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In order to solve the problem you may try to reduce the amount of water. If the
problem persists, re-evaluate the paste.
Clogging: Infiltration Test
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Required equipment, tools and material
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Water.
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Container to hold the water.
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Insitu infiltration rate equipment (infiltrometer).
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Timer able to measure to the nearest 0.1s.
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Preparation
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Mark out several designated areas for testing over the life-span of the concrete
(preferably on a drawing).
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It is important to maintain the same area for testing because the infiltration rate
is greatly influenced by the height and compaction of the base and Hydromedia
layers.
Procedure
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Place the in situ infiltration rate equipment on the designated area with the ring
placed at the bottom.
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Pour 3 L of water in the top portion of the equipment.
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Release the valve and begin timing the water until it reaches 1 and ends at 2.
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Record the time it took the water to complete testing.
Analysis
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Clogging Indicator = volume/area/time.
SPECIFICATION SHEET
GREEN RATING SYSTEMS
Environmental certifications have become more and more used to assess the quality of
buildings. LEED, BREEAM and HQE are the most used worldwide and cover a large part of the world.
Below are Hydromedia contributions to these certifications.
Leadership in Energy and Environmental Design – LEED Project Certification:
Sustainable Site Selection
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SSc6.1-6.2 Stormwater Management
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SSc7.1 Heat Island Effect, Non-roof
Materials and Resources
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MRc4 Recycled Content
Innovation in Design
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IDc1 Innovation
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RPc1 Durable Building
BRE Environmental Assessment Method – BREEAM
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Pol 5.1: flood risk
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Pol 5.2 Surface water run off
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Pol 5.3 Minimizing water course pollution
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Pol 6 Minimizing watercourse pollution
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WST 2 Recycled Aggregates
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Mat 5 Responsible sourcing of materials
Haute Qualité Environnementale – HQE
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Target 1: Harmonious relationship between buildings and their immediate environment
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Target 3: Integrated choice of materials, systems and processes
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Target 4: Energy management
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Target 5: Minimizing water use
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Target 8: Hygrothermal comfort
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Target 11: Measures to control smells
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Target 13: Air quality
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Target 14: Water quality
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EFFICIENT BUILDING SYSTEMS
Lafarge has created EFFICIENT BUILDINGTM that encapsulates its response and contribution
to the new challenges of sustainable construction. Listed below are all efficient building systems that
apply to Hydromedia. Upon request Lafarge can supply the following documents.
Pervious concrete pavement - Hydromedia
SPECIFICATION SHEET
REFERENCES
ASTM (American Society for Testing and Materials) - www.astm.org
ACI (American Concrete Institute) - www.concrete.org
CEN (European Committee for Standardization) - www.cen.eu/cen/
ASCC (American Society of Concrete Contractors) - www.ascconline.org
LEED (Leadership in Energy and Environmental Design) - www.usgbc.org
BREEAM (BRE Environmental Assessment Method) - www.breeam.org
HQE (Haute Qualité Environnementale) - assohqe.org/hqe/

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