Technical details of sites

For the creation of  90° angles, two possible solutions are available:

• place panels close one to another in order to create the corner.
• cut panels with a 45° angle, thus creating the corner.

In the first case, the Jolly panels will be installed close one to another in the external part and the internal panels will be cut to size according to the specifications provided by Rexpolgroup. Then the spacers will be placed in order to obtain the correct concrete section. The elements (formworks) thus created, will be then propped up externally to prevent them from opening during the casting process. If panels with a 45° cut are installed, they must have been previously cut, (according to Rexpolgroup specifications) and then has to be inserted an internal plastic angular element. The next phase is the installation of the spacers, to obtain the correct concrete thickness. Those elements must be then reinforced in the points of the internal surface where the panels are connected, to maintain their perpendicularity during the concrete casting process.

Data sheet

Creation of “T” junctions

For the creation of “T” junctions the line of internal panels has to be cut in a specific point to allow the insertion of the formwork-block (EPS+ spacer +EPS) that will constitute the new intersection. The panels, both internal and external, must be cut to size according to the specifications provided by Rexpolgroup. Then the second step is the positioning of the spacers to obtain the correct section of concrete. The spacers must then be externally propped up to prevent their opening during the casting process, and also internally reinforced to maintain the correct alignment and orthogonality.

Shoring of the corners

In the case that panels have clean-cut corners, a wooden scantling or a metal bar has to be placed in the internal corner, and then secured to the internal structures of the multi-section tracks, using special straps. The scantling must be maintained vertical with the help of wooden boards or props attached to it. This will have the function of preserving the correct alignment of the panels and the vertical position of the corner. Then will be placed a wooden or metal angular element in correspondence of the external corner, to prevent the formwork from opening. Two wooden scantlings will be then placed in the middle of the concrete wall, incident to the panel, to oppose the pressure of the concrete. These elements have to be well anchored to keep the pressure: both must be externally shored in three different points or tied with external ties. Shoring the corners has the function to oppose the  pressure of the concrete, so it’s an essential operation to be performed.
If using the 45°cut corners, first has to be checked if the angular element is properly positioned and fixed. Then a wooden scantling or a metal bar will be placed in the internal corner and fixed with special straps to the internal structures of the multi-section tracks. The scantling must then be maintained vertical with the help of wooden boards or props attached to it. This will have the function of preserving the correct alignment of the panels and the vertical position of the corner. Then a wooden or metal angular element will be placed in correspondence of the external corner to avoid losing  perpendicularity.

Data sheet

Shoring of the “T” inserts
In the case that T” inserts have to be created, first of all a wooden scantling or a metal bar has to be placed in each of the two internal corners and then anchored to the internal structures of the multi-section tracks using special straps. The scantling must then be maintained vertical with the help of wooden boards or props attached to it. This will have the function of preserving the correct alignment of the panels and the vertical position of the corner. Two wooden scantlings will be then placed in the middle of the concrete wall, incident to the panel, to oppose the pressure of the concrete. You will need to anchor them well to keep the pressure: both elements must be or shored in three points (externally), or tied using external ties. The shoring process has the function to oppose the  pressure of the concrete, so it’s an essential operation to be performed.

Data sheet

Installation of the temporary frames/couterframes

After the creation of the holes, temporary frames or counterframes have to be placed within them. These elements have the function of opposing the pressure of the concrete during the casting phase. First of all, a wooden scantling or a metal bar has to be placed in each of the two internal corners and then anchored to the internal structures of the multi-section tracks using special straps. The scantling must then be maintained vertical with the help of wooden boards or props attached to it. This will have the function of preserving the correct alignment of the panels and the vertical position of the temporary frame/counterframe. To guarantee that the structure will be able to opposes the pressure of the concrete, a defined number of props for windows must be placed (see the illustrations below). These props must be nailed to the frame in order to avoid any unwanted movement. The lower part of the temporary frame or counterframe must be opened in order to fill up any potential “V” shaped gap in the concrete. However it has to be easily resealable in the case that concrete leaks  upward.

Data sheet

Concrete casting specifications

The best suggested method to cast the concrete, is by using a concrete mixer or a pumper geared with a telescopic arm. Alternatively it can be used a ramp (if an easy access to the entire perimeter is guaranteed) or a bucket system.
Using a pump for concrete, a very expert team is able to obtain a casting speed from 15 to 20 m³ per hour. In order to ease the casting process and to obtain the best possible results it is highly suggested to pour a well-mixed mixture in the pump for concrete. When using a pumper geared with an arm you MUST specify to the supplier of the pumper that two 90°(S-shaped) handles have to be installed directly on the terminal of the arm, to reduce the impact of the concrete when it falls inside the formwork. This determines a more stable, uniform and homogeneous flow of concrete, making the casting process easier to be performed. For a better handling, apply one or two grips on the 90° handle.
Always discard the first amount of concrete coming out from the pump (that is usually sludge) and do not insert it inside the formwork. Cast the concrete with a constant, moderate but firm flow and avoid aggressive casting in the corners. In order to obtain a proper solidification, do use a well mixed and fluid concrete mixture. It is strongly recommended the use of an additive in the concrete, such as a super-fluidifier or a similar product, in order to reduce the water content; this precaution has the purpose of optimizing the concrete flow. Do not vibrate the concrete with normal concrete vibrators as they may create problems when leaning agaist the spacers or the rebars. Moreover, an increase in pressure due to the vibrations could make the system collapse in some points. To avoid this problem, if needed, it’s possible to indirectly hit with a hammer a piece of wood, in contact with the wall. This can be useful to cast the concrete better, especially near the openings/lintels or where the rebar has been reinforced.
The walls can be filled in one or two phases. Start from the midpoint of a wall (at maximum 610mm from the corner) and proceed with the concrete cast.The particular design of the ICF REXwall formworks allows the walls, to a certain extent, to vibrate independently while casting the concrete. The effect of the vibration of the wall allows the concrete to slide downward with a considerable but gradual flow, allowing the correct distribution of the concrete around the rebars, the spacers and inside the dovetail sections. In this way any defect of the wall due to an inaccurate casting are avoided, preventing the formation of air bubbles, gaps and spaces that are not perfectly filled with concrete.
The openings such as those for the doors and windows can’t be filled first on one side but must be filled together, moving alternately from side to side to avoid unequal mechanical stresses. Make sure that the spaces or gaps under the bottom of any opening (windows, doors, pipes, etc.) are completely filled. Continue in the same direction, firmly filling the walls. Go back to the starting point as quickly as possible.

precast ceck-list

Concrete specifications

problem management

Specifications of the rebars

The installation of the horizontal rebars has to be performed as follows. The first row of rebars must be positioned in the most external eyelet of the spacer. In the second row instead, the rebars must be positioned in the most internal row of supporting eyelets. When placing the rebars, make sure that they pass through the supporting eyelets correctly. The positioning of the vertical rebars will be made by inserting the bars from above. The structure created by the alternation of the horizontal bars (previously placed in the internal and external eyelets), will be used as a support to keep the rebar vertical. In this way the rebar will maintain its vertical position automatically, so it has to be tied only in the upper part. In case that the building project indicates the need for thickening the rebars, it is possible to break the spacer into two pieces, thus determining different interaxle spacing. ICF REXwall system has been arranged to obtain a medium interaxle spacing of 35 cm from the horizontal rebars to the whole spacer. When a shorter interaxle spacing is required, the spacer can be simply divided into two identical parts thanks to a special track.
In this case it will be possible to alternate whole and split spacers so as to obtain a medium interaxle spacing of 26, 25 cm. If necessary, it will be possible to insert only broken-in-half spacers, thus obtaining an interaxle spacing of 17, 50 cm.

Data sheet