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82 4.1 Concrete Mix Design

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4.1 ConCrete Mix DesignThe design of the concrete mix must comply with all applicable codes and engineering requirements of the project. The concrete delivered to the job site should meet the specifications necessary to achieve the design strength and assist proper placement and consolidation of the mix.

There are many factors that govern the design of concrete for use on construction sites, such as environmental conditions, structural considerations, and aesthetics. Since concrete used in ARXX ICF walls is not usually visible, it is recommended to concentrate on environmental and structural concerns.

Environmental factors that influence the design of concrete materials include temperature, presence of water when considering marine applications, wind, and direct and indirect sunlight. Many of these factors are eliminated by using an insulating concrete form. The use of insulating concrete forms permits contractors to place concrete during cold winter months. As the concrete cures, it generates heat. In conventional formwork, this heat is dissipated into the air through and around the forms. With an insulating forming system, the heat generated is easily retained within the form, eliminating the need for insulating blankets, supplementary heating, and chemical additives to prevent freezing.

Refer to the ARXX Technical Bulletin Cold Weather Concreting, for further information regarding cold weather installations.

Figure 4.1-1 Compressive strength oF ConCrete

83 4.1 Concrete Mix Design

ARXX insulating concrete forms can also provide better quality concrete in warmer climates. Conventional forming systems are removed as soon as possible, leaving the wall to lose its moisture much more quickly when exposed to the sun, wind, and air in the dry summer heat than a wall that is left in a moist curing environment inside an insulating concrete form system. As stronger concrete can be achieved by leaving forms in place as long as possible, stay-in-place insulating concrete forms will therefore yield a stronger, more durable concrete than conventionally formed walls that are air cured.

The advantage of curing concrete within an ARXX ICF walls is that the walls develop a high strength very early in the curing process, and they are known to exceed the expected design strength over 28 days.

4.1.1 ConCrete Design speCifiCationsIn accordance with the IRC and the NBCC, the minimum requirement for compressive strength of concrete in ICF walls is 2500 psi (20MPa) at 28 days. ARXX documentation and design tables used in this guide are based on this design.

Residential construction projects may use the code minimum requirements for the compressive strength of concrete, as specified herein. However, for all projects, the architect/engineer of record dictates the specifications for concrete design.

The water/cement ratio shall be less than 0.60. It is recommended to use type 10 (type 1 in the United States) normal Portland Cement on ARXX

projects, unless otherwise specified.

4.1.2 ConCrete slumpConcrete slump is the measure of the ability of concrete to flow freely. Slump can be measured by pouring concrete into a cone, as shown in Figure 4.1.2-1, consolidating it with a rod, and then turning the cone over on a flat surface to remove the concrete. When the rod is held horizontal and level across the top of the cone, the distance to the top of the concrete from the underside of the rod is measured and this is the slump number.

ARXX recommends a slump of 5.5 to 6.5 (140 mm -165 mm).

Placing concrete in an ARXX ICF wall with a slump that is lower than 4 (125 mm) may damage the forms and will not provide a flow that is adequate to fill the cavity between the webs and around the rebar.

It is not recommended to alter the water to cement ratio of the concrete mix. Altering the water to cement radio could possibly influence the compressive strength and weaken the concrete, as adding one gallon of water per cubic yard reduces the concrete strength by 150 psi (1 MPa), according to the PCA rule of thumb.

Recommended concRete slump should be attained thRough the addition of chemical add mixtuRes and not the addition of wateR.

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84 4.1 Concrete Mix Design

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Figure 4.1.2-1 slump testing

under 5.0 slump is too low 5.0 - 6.5 slump is CorreCt over 6.5 slump is too high

4.1.3 ConCrete aggregateIt is recommended that the concrete aggregate used in ARXX forms is specified to the size of the forms.

concrete cores 6 (150 mm) and under use 3/8 (10 mm) or smaller aggregate concrete cores over 6 (150 mm) use to (13 mm to 19 mm) aggregateTo faciliTaTe The besT flow of concreTe wiThin The wall, The form core size and reinforcemenT layouT dicTaTes The aggregaTe size.

4.1.4 orDering ConCreteMost ready-mix concrete plants have developed an ICF mix design that incorporates the correct aggregate and water to cement ratio to provide the recommended slump for ARXX projects. It is recommended that when ordering concrete for a project, specify the ICF mix design with the required aggregate and slump, as recommended by ARXX design and the specifications of the architect/engineer of record.

Upon site delivery, it is recommended to confirm the order has arrived as specified.

4.1.5 aDDitivesConcrete admixtures can be used in ARXX forms. Consult with your ready-mix supplier.

4.1.6 innovationsThere are a number of innovations in concrete design that may be used in the application for ARXX forms, including self consolidating concrete and fiber reinforcing concrete, using metal or polypropylene fibers. The application, installation, engineering design, and technical support for the use of innovative concrete design is the responsibility of the concrete product manufacturer and supplier or design professional when used with ARXX forms.

85 4.1 Concrete Mix Design

4.1.7 green ConCreteSupplementary cementitious materials (SCM), such as Fly Ash or Slag Cement, are recycled materials that are recognized as an advantage in green and LEED rating evaluations. Substitutions of up to 50% of supplementary cementitious materials can reduce necessary cement requirements, while maintaining a specified ultimate concrete compressive strength. High volume substitutions with an SCM can dramatically reduce embodied energy and the generation of greenhouse gas emissions in concrete.

If SCMs are incorporated into the mix design, it is recommended that the contractor ensure that the concrete producer supply proof that the final concrete quality will not be altered by replacing portions of the Portland Cement with supplementary cementitious materials.

Concrete mixtures using SCMs may increase form pressure.

The conTracTor musT ensure ThaT The concreTe producer is providing a producT ThaT meeTs The requiremenTs of The local building code and/or The specificaTions of The archiTecT/engineer of record

minimum compressive sTrengTh of The concreTe musT meeT code requiremenTs or projecT specificaTions. iT is recommended ThaT The compressive sTrengTh is measured aT 28 days, unless oTherwise specified.

supplemenTary cemenTiTious maTerials (scm) are considered posT-indusTrial maTerials conTribuTing To leed poinTs.

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86 4.2 Prior to Placement of Concrete

4.2 prior to plaCeMent of ConCrete

4.2.1 plaCeMent proCeDuresTo aid in adjusting the straightness of the wall prior to, during, and following placement of concrete into the ARXX forms, it is recommended that a string line is fastened at the top perimeter of all walls under construction. Prior to placing concrete in the ARXX forms, the walls are required to be plumb and any adjustments necessary made using the string line. Tilting the walls slightly inwards may compensate for any shifting that can occur due to concrete placement and working from the scaffolding during concrete placement. It is easier to plumb a wall by pushing the wall out with the adjustable pole on the alignment system than it is to pull the wall in after concrete placement.

It is recommended to review the following areas to ensure that they have adequate support :

ICF block cuts that are more than 4 (100 mm) from a web outside corners or butt joints or mitered corners top courses T-walls edges of all openings, buck bracing, and vertical joints taper top and brick ledge form edges

When ARXX forms are to be continued for another stage of construction, it is recommended that the top of the forms be protected from being soiled with concrete, so that the interlocking mechanism will be clean and undamaged. The top of the forms can be protected by covering the top of the wall forms with 2 (50 mm) wide tape or poly or a 2 (63.5 mm) steel stud base channel that fits over the EPS panels to provide the required protection. Once the concrete placement has been completed, the protection caps can be removed.

It is recommended that a concrete crew is established and responsibilities for each task are assigned as follows:

one person to place concrete two people for consolidation one person to monitor the walls extra manpower, as required

In section 4.2.2 Pre-Placement Checklist, there is a checklist which should be copied and used on every project site.

The Top course of forms should be fasTened TogeTher end To end wiTh Tie-wire, zip-Tires or arXX claws To prevenT movemenT during concreTe placemenT. addiTionally, The Top Two courses should be secured TogeTher by Tie-wire, zip-Ties or arXX hooks To prevenT The accidenTal dislodging of The Top course during concreTe placemenT. iT is recommended ThaT The Top Two courses are connecTed TogeTher verTically aT 16 (406 mm) o.c.

follow The pre-placemenT checklisT.

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87 4.2 Prior to Placement of Concrete

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4.2.2 pre-plaCeMent CheCklistThe following checklist can assist an ARXX ICF installer prior to placing concrete. The use of this checklist is recommended on each ARXX installation. The list is not intended to be exhaustive, so installers are encouraged to add any steps and precautions to it to ensure a safe and efficient job.

Review the concrete estimate and the order. Ensure that the rebar has been inspected and approved for concrete, if required. Check that the concrete ordered is the proper strength, per code or Engineer. Confirm concrete delivery times and pump truck arrival time. Review the weather conditions and prepare for the worst case scenario. Ensure that all form supports and strapping have been installed. Confirm that elevations and pour heights have been established. Ensure the walls are constructed according to the layout. Ensure the alignment/scaffold system is installed properly. Ensure scaffold planks are secured and safe. Ensure all openings are installed. Ensure the reinforcement bars have been placed in the wall and around all openings, as specified. Ensure anchors have been provided for buck anchorage in the concrete. Ensure bucks have been secured to the forms and cross braced. Ensure all service penetrations are installed. Confirm that the top course of forms are secured to the course below. Ensure all corner forms have been secured. Ensure beam pockets have been provided. Ensure the floor system anchorage has been installed. Ensure that a trowel is available and prepared to recess the sill plate, if required. Ensure dowels are prepared as required. Ensure anchor bolts and any other items to be embedded are on site to insert into the concrete. Ensure the walls are straight and tilted inward, as recommended. Ensure that the top course interlocking has been protected from filling with concrete. Check that tools available for consolidation are available and in working order, including internal

vibrators with a shaft length sufficient to reach to bottom of the wall. Check that strapping material and screw guns are readily available in case of a blowout. Ensure spray foam is installed in any large seams or holes in the EPS. Ensure that there are materials prepared to protect the exposed concrete at the top of the wall from

freezing, snow or rain. Check that there is room for the concrete truck and pump truck to maneuver.

The checklist and recommended practices are recognized as best practices for the installation of ARXX forms. ARXX Corporation has no control over the installation, workmanship, accessory materials, conditions, or application of its products. Accordingly, no responsibility or expressed warranty, either as to merchantability or fitness for the particular purpose, is made as to the performance or results of an installation using ARXX forms.

This checklisT is reprinTed in The arXX field guide, for on siTe convenience. The arXX field guide is available on The arXX websiTe www.arXX.com.

iT is recommended To walk around The projecT To view all The walls, inside and ouTside, and anTicipaTe any poTenTial problems ThaT may need aTTenTion prior To placing concreTe.

88 4.3 Concrete Placement

4.3 ConCrete plaCeMent

4.3.1 ConCrete plaCeMent overviewThere are several traditional methods of concrete placement that can be used with ARXX insulating concrete forms including concrete pump, line pump, crane and bucket (for commercial applications), conveyor belt, or direct off the truck chute.

The easiest method for placing concrete in an ARXX ICF wall is with a concrete pump or boom truck. It is recommended that when choosing a concrete method, the nature and scope of the project is taken into account, including the practicality and availability of equipment, to determine the method used. Whichever method is chosen, care should be taken to ensure that the job site is clean, clear and accessible, including the appropriate clearance from overhead utility lines, for the equipment.

ensure ThaT all areas of The projecT can be reached by The concreTe delivery sysTem.

scheduling ensure ThaT There is enough Time for The pump Truck seT-up before The concreTe arrives. iT is recommended To order The firsT concreTe Truck delivery To be half hour afTer The arrival of The pump Truck and Then The following concreTe deliveries on The conTracTors call once The pour is successfully underway.

concreTe pump when using a concreTe pump, iT is recommended To order The Truck wiTh a line reducTion To a 3 (89 mm) fleXible hose, which will reduce The velociTy of The concreTe as iT is dropped inTo The forms.

conveyor belT for some projecTs wiTh low heighT walls a conveyor belT wiTh a concreTe Truck may be used. as The Truck may need To be moved a number of Times around The projecT, ensure ThaT iT can reach all of The walls.

direcT off Truck chuTe This meThod is only feasible for minimum heighT and below grade walls. iT is recommended To ensure ThaT The speed of concreTe delivery inTo The wall, direcTing The concreTe from The chuTe down inTo The wall, and consolidaTion and Truck access are all appropriaTe for The projecT.

4.3.2 plaCeMent rateThe speed of concrete placement has many variables that must be considered prior to initiating placement of concrete in the cavity of an ARXX ICF wall. For example, the linear length of wall, temperature, consistency of concrete mixes, height of wall, and cement content are all factors that affect placement rate. The placement rate will also vary with the method being used to fill the ICF forms. Concrete pour rates should not exceed the limitations in the table below, as set out by the standards of the American Concrete Institute.

Pour rates in the following Table 4.3.2-1 reflect a 2:1 safety factor, as suggested by the ACI. These rates assume a normal density concrete (150 pcf (2400 kg/m3) or less) combined with air temperatures. Concrete within the insulating concrete forms generally maintains its delivery temperature from the truck, but as it cures in the ICF, it generates heat.

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89 4.3 Concrete Placement

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table 4.3.2-1 plaCement rate

TemperaTure F (C) FeeT/Hour (mm/Hour)

40 (4) 2.2 (670 mm)

50 (10) 2.9 (890 mm)

60 (15) 3.4 (1040 mm)

70 (21) 4.0 (1220 mm)

80 (27) 4.6 (1400 mm)

90 (32) 5.2 (1585 mm)

4.3.3 liftsConcrete is placed in ICF walls in multiples of lifts, with a maximum lift height of 48 (1220 mm) every hour. Each pass around the wall perimeter is considered a lift. Maximum lift height is determined by temperature, and the recommended lift height decreases as the air temperature gets colder (see table 4.3.2-1).

In order to complete the safe placement of concrete in an ICF wall, ensure that the work crew is aware of the placement rate and lift height. Lift heights should be considered so that the top lift is approximately 24(610 mm) as it is more efficient for pumping concrete into the wall cavity and will minimize spillage due to overfilling the last lift to compensate for consolidation.

It is recommended to place concrete by lifts, as this method allows the lower lift of concrete to start curing so that it is able to offer some support for the next lift, thus minimizing the pressure on the bottom of the form (see 4.3.4 Form Pressure). Using this method, an 8 (2.4 m) high wall may be completed in two lifts, a 10 (3.0 m) to 12 (3.6 m) high wall in three lifts, etc. It should be noted that placing concrete in lifts does not limit the overall height of the concrete pour in a wall in any one work day.

4.3.4 forM pressureDuring concrete placement, the concrete exerts outward pressure on the ICF forms, which is known as form pressure. ARXX forms are designed to withstand this outward pressure in accordance with the guidelines; however, when installing ARXX forms the recommended guidelines must be followed in order to avoid dangerously increasing the form pressure, which can cause bulging or failure of the form resulting in a blowout.

The outward pressure is highest near the bottom of a lift. As the concrete sets, the pressure gradually reduces to near zero. By the time the second lift begins, the concrete of the first lift has started to cure slightly so that the likelihood of difficulties in the bottom of the wall decrease significantly. Similarly, as the second lift is poured, the highest pressure occurs at the bottom of the second lift.

When consolidating the concrete, it is recommended to extend the internal vibrator into the lift below in order to blend the two lifts and avoid a cold joint. However, excessive internal vibration can increase form pressure significantly.

90 4.3 Concrete Placement

Figure 4.3.4-1 Form pressure gradient

Figure 4.3.4-2 Form pressure per liFts

4.3.5 ConCrete free fall heightConcrete testing and industry reports indicate that the free fall of concrete from heights of up to 150 ft (46m), either directly over rebar or with high slump concrete, does not cause segregation or reduce the compressive strength of the concrete. Concrete design for ICF walls is considered to be high slump.

It is recommended to internally vibrate the concrete to ensure proper consolidation and to eliminate any potential for segregation.

4.3.6 ConCrete plaCeMent proCeDures1. Before beginning concrete placement, the Pre-Placement Checklist should be checked and followed. All control signals with the pump truck operator should be confirmed and it should be ensured that the crew and the project are ready to complete a continuous pour.

2. It is recommended to begin at the center of wall, typically close to the pump, and work toward the corner, allowing the concrete to fill to the desired lift height. Care should be taken to ensure that the concrete flows at a 30 angle. In order to evenly distribute the concrete and minimize the

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91 4.3 Concrete Placement

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Section 4.3.6 (continued)

pressure, the concrete hose should be swung in a back and forth motion while moving along the wall perimeter. The concrete in the wall should be monitored for the flow, congestion, air pockets and voids in the flow around rebar, webs and service penetrations. Best practices prescribe traveling in one direction around the perimeter of the building and completing each lift back to the starting position.

3. In order to reduce concrete pressure directly on corner forms, it is not recommended to direct concrete directly into a corner. The concrete should be allowed to flow into corners from 2 to 3 (610 to 915 mm) away on either side of the corner.

4. As part of the first lift, concrete should be placed below the window and door openings, so that when the remainder of the wall is filled, a void is not created either below or at the corners of the openings. If the bottom of the window and door openings do not fill completely, the hose can be lowered down to completely fill them or excess concrete can be used to fill them at the end of the concrete placement.

5. When concrete is placed in a T-wall, the straight portion of the T-wall is placed first and the intersecting wall is subsequently placed to minimize concrete pressure on the outside form.

6. During concrete placement, it is recommended that the installer monitor the alignment of the wall relative to the string-line. Regular monitoring will make the job of final alignment much easier.

7. A concrete pour is continuous until the desired pour height is reached. It is important to understand and follow recommended practice to terminate the concrete at the top of the wall, either as a construction joint or a cold joint. Concrete placement may be stopped at any time in the wall, at any level, as long as appropriate steps are taken to ensure that the next pour is bonded to the previous pour.

8. Care should be taken to ensure that the top of the form's interlocks are clean in order to enable stacking the next course of forms.

9. All the anchor bolts, or other items to be embedded in the concrete, should be checked to ensure that they are properly secured and consolidation is sufficient around all sides.

10. The walls should be rechecked in order to ensure that they are plumb and level.

11. The Post Concrete Checklist described in Section 4.6 should be followed following concrete placement.

concreTe placemenT musT be in accordance wiTh csa a23.1. and csa a438 in canada and aci 318 or aci 332 in The uniTed sTaTes.

concreTe is a harsh maTerial ThaT can burn eXposed skin and eyes. proTecTive cloThing, gloves, eye wear and a hard haT should be worn when working wiTh concreTe.

placing concreTe Too rapidly can cause The forms To bulge, rupTure or move ouT of posiTion, poTenTially creaTing a safeTy hazard, and sTrucTural issues, including crooked walls.

92 4.4 Consolidation of Concrete

4.4 ConsoliDation of ConCrete

4.4.1 ConsoliDation of ConCrete overviewTo ensure proper concrete consolidation, all concrete walls require internal vibration, in accordance with ACI 309R Guide for Consolidation of Concrete. Each layer of concrete must be properly consolidated to embed the reinforcing bars and webs properly and to eliminate honeycombing. To prevent cold joints, each successive lift must be properly consolidated with the previous lift. The slump of the concrete is the most critical factor in determining the amount of consolidation required for each concrete pour.

improperly consolidaTed concreTe can resulT in sub-sTandard resulTs, including waTer leakage Through The wall and insufficienT wall sTrengTh.

consolidaTion musT always be accomplished in lifTs. an enTire wall cannoT be consolidaTed aT one Time.

4.4.2 ConCrete vibratorsThe maximum recommended diameter for a concrete vibrator is 1 (25 mm), however the preferred size is (19 mm) diameter, as larger sized vibrators can get caught in the webs or reinforcing bars and may create unwanted additional form pressure, which can potentially lead to form failure. An electric or gas powered vibrator with a maximum horsepower rating of 1 HP is recommended.

When choosing the appropriate concrete vibrator, care should be taken to ensure the best balance of frequency and amplitude for the job. As well, the vibrator shaft length must be sufficient to reach to the bottom of the internal cavity. For taller walls, temporary access ports may be cut in the side of the wall. The EPS is replaced and reinforced with plywood attached to the webs each side of the port.

When using concrete vibrators, care should be taken to use proper consolidation techniques, which consolidate concrete from the bottom of the form towards the top. The objective of consolidation is to remove trapped air inside the freshly poured concrete. It is recommended to insert the head of the vibrator quickly and remove it slowly. This technique is commonly referred to as fast-in and slow-out. Pulling the head up slowly helps move the trapped air up to the surface. In ideal conditions, the vibrator is pulled out at a rate of 3 (75 mm) per second while the vibrator is kept continuously moving.

Figure 4.4.2-1 vibrator

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4.1.2-1

4.4.1-1

93 4.4 Consolidation of Concrete

proper Technique is required when vibraTing inTernally. over vibraTion will cause eXcessive pressure on The forms, poTenTially leading To bulges and blow-ouTs.

4.4.3 alternative MethoDsSmaller construction projects may not have internal vibrators on site. These sites require alternative methods for consolidating the concrete. These include:

Hand rodding which is done while the forms are being filled. This is an effective method which ensures that proper rebar embedment is achieved.

External vibration which is the use of drills or reciprocating saws with specific adaptors that can accomplish concrete consolidation.

Rebar vibrators which are attached to each vertical rebar to achieve concrete consolidation.Another complementary consolidation technique is a manual method that uses a wood block and mallet to tap against the wall; however, this technique is only recommended to be used in addition to one of the other methods described above.

once The concreTe is placed, iT is imporTanT To confirm ThaT The concreTe is aT The correcT heighT, The wall is sTraighT along The fooTing, level and plumb. iT is recommended To use The sTring line ThaT was erecTed prior To concreTe placemenT and The Turnbuckles in The alignmenT sysTem To ensure ThaT The wall is sTraighT and True.

consolidaTion of concreTe musT be in accordance wiTh csa a23.1 in canada and aci 318, aci 332, aci 309r in The uniTed sTaTes.

when The walls are being vibraTed, maXimum pressure will occur aT The boTTom of The forms. iT is recommended To waTch carefully To ensure ThaT forms are noT bulging or showing signs of failure due To over vibraTion.

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94 4.5 Completion of Concrete Placement

4.5 CoMpletion of ConCrete plaCeMent

4.5.1 top of finisheD wallsWhen the wall does not need to be continued, the concrete will need to be finished at the top of the wall, thereby providing a relatively smooth, level surface. Typically, a wooden sill plate and anchor bolts are installed, which provide attachment for either floor joists or roof trusses/rafters.

Figure 4.5-1 homemade trowel

4.5.2 roof sill platesIt is recommended that roof sill plates are set inside the wall between the EPS panels, to maintain the maximum insulation at the top of the wall. Making a trowel from a short piece of plywood attached to a section of plate material, is the simplest way to provide consistent troughs for the sill plates. The plywood acts as a guide, as it slides on top of the EPS panels, and the plate creates a void at the top of the wall that is the perfect dimension to install the sill plates.

Anchor bolts should be placed once the wall is finished. Refer to design drawings and local building code requirements for their size and spacing.

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CONCRETE CORE WIDTH

95 4.5 Completion of Concrete Placement

Figure 4.5.2-1 detail oF sill plate in wall

4.5.3 floor sill platesWhen a wall is terminated at the floor sill plate level, then the floor sill plates will typically sit on top of the concrete, rather than being recessed into the form. The concrete is troweled smooth and to the desired level, and thereafter the anchor bolts are inserted.

when conTinuing a wall, iT is imporTanT ThaT The Top of The forms are clean, which provides a good inTerlocking connecTion for The neXT row of forms.

in eXTreme weaTher condiTions such as cold and weT weaTher The Top of The wall and The cold joinT should be proTecTed from ice, snow and eXcessive waTer. The concreTe aT The cold joinT musT be clean and free of snow, ice and debris before The placing of The neXT lifT of concreTe.

iT is recommended To insTall or finish The wooden sill plaTes wiTh an air seal gaskeT or a compaTible sealanT under The plaTe. sealing wooden sill plaTes prevenTs air infilTraTion from The eXTerior To The inTerior of The building envelope.

The insTallaTion meThod and spacing for maTerials ThaT are going To be embedded inTo The concreTe on Top of The wall, such as anchor bolTs or hurricane sTraps, should be Taken inTo consideraTion.

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96 4.6 Post Placement Checklist

4.6 post plaCeMent CheCklistThe following checklist is intended to assist the installer of ARXX ICFs to complete a number of post placement checks and procedures prior to leaving the project jobsite. The list is not intended to be exhaustive, so installers are encouraged to add any steps and precautions to it in order to ensure a safe and efficient job.

Ensure that all the walls are plumb and straight. Ensure that the concrete has been properly consolidated. Ensure that all tight areas, such as the corner of openings, joist/beam pockets, etc. have been

consolidated. Ensure that the tops of the walls have been checked for correct design height and confirmed that

they are level. Ensure that the walls have been troweled off. Ensure that the anchor bolts and connectors have been installed. Ensure that all the floor connectors and embedments are installed and are tight to the wall. Ensure the alignment systems are secured, ensuring that the walls are plumb and straight. Check that adequate bracing been installed, inside and outside, to anticipate any weather

conditions such as high winds that may influence the walls while they are the curing. Ensure all exposed concrete surfaces are protected from freezing or heavy rain. Ensure that the top of the forms are clean for continuation of building with ARXX forms. Check that the concrete has been cleaned from the alignment/scaffold systems, has been

cleaned off the slabs/footings, and the tools have been cleaned. Check that the walls have been re-checked to ensure they are straight and level. Check that all service penetrations are open and in good condition after the concrete placement.

The checklist and recommended practices are recognized as best practices for the installation of ARXX forms. ARXX Corporation has no control over the installation, workmanship, accessory materials, conditions, or application of its products. Accordingly, no responsibility or expressed warranty, either as to merchantability or fitness for the particular purpose, is made as to the performance or results of an installation using ARXX forms.

The alignmenT/bracing sysTem should noT be removed unTil The concreTe has reached adequaTe sTrengTh, which is usually wiThin 3-5 days.

iT is noT recommended To backfill below grade walls prior To The firsT floor being insTalled, unless adequaTe bracing is in place, which will wiThsTand The pressures of The backfill on The wall.

iT is noT recommended To load The new walls wiTh eXcessive uniform or poinT loads such as a modular home, unTil The concreTe has reached a minimum of 45 % compressive sTrengTh, which Takes place wiThin 7-14 days. maXimum concreTe sTrengTh is achieved in 28 days.

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