tech-solution

TECHNICAL SOLUTIONS

Area of application

Technical solutions for application of polystyrene concrete works were developed by NORTEC COMPANY in compliance with requirements of regulatory documents of the Republic of Uzbekistan as guidelines for application of polystyrene concrete works for construction of buildings meeting the enterprise standard Ts24196002-02:2014 “Thermal insulating materials from polystyrene concrete. Technical specifications”. The works are used as thermal insulating non-load bearing load bearing element elements.

NORTEC COMPANY recommends to follow technical solutions for designing and installation of items from thermal insulating polystyrene concrete tiles (here and after PCT), tong-and-groove shaped polystyrene concrete blocks (here and after PCBTG), as well as profiled polystyrene concrete composite slabs (here and after PPCCS) (currently prepared for production in Uzbekistan).

PCT are used for thermal insulation of outer walls, columns, joists, bond beams, garret and basement floors of buildings of different functions with dry, normal and wet operating conditions.

PCBTG are used for construction of non-load-bearing outer walls as cladding of self-bearing walls when arranging outer shell of multi-storey buildings and load-bearing composite walls for one-storey buildings (with attic floor).

PPCCS are used for construction of load-bearing floor structures and roofs of buildings and structures in package with in situ reinforced concrete beams (from heavy weight concrete).

The advantages of polystyrene concrete works include high heat insulation, light weight and stress-strain properties meeting the requirements of standards for application in constructions, which is stipulated in the enterprise standard Ts24196002-02:2014 considered jointly with these technical solutions.

General views of PCT, PCBTG and PPCCS are provided in pictures 1-3.

Плиты 600х400х60мм

Picture 1. Polystyrene concrete tile (PCT)

Блоки 200х300х500мм

Picture 2. Polystyrene concrete blocks (PCBTG)

Polybetonprofslab image

Picture 3. Profiled polystyrene concrete composite slabs (PPCCS)

General provisions

         PCT, PCBCG, PPCCS items may be manufactured from materials with density from 150 to 600 kg/ m3, i.e. of grades D150 – D600. Herewith concrete grades and classes with regard to compression strength – М2-М7.5, В0.35-В2.5.

For PCT the recommended density is within D250 –

D300, compression strength is within M2 – M7.5, and specific purpose depends on design solution of application area. The lower density, the lower strength, but the higher heat insulation of item. In this connections when accepting any design solution it is required to specify a value of density and strength. At customer’s option tiles may be reinforced with lightweight wire mesh, which improves their safety during transportation, installation and finishing without damages (chips or breakage).

For PCBTG recommended density is within D300 – D450 for outer wall cladding. The compression strength is within B0.75 – B1 (1,09 – 1,45MPa)  according to design solution. These characteristics should be within acceptable limits of p.2.1. CMC 2.03.07-98 “Masonry and reinforced masonry structures” for lightweight concrete bricks.

Calculation of special load combination of block work under action of forces from plane, such as cladding with horizontal dimension being 5600 mm (between columns in clear) in the plan, height being 2600 mm (from top of floor slab to bottom of  flooring joist) demonstrates sufficiency of recommended stress-strain properties to assure design reliability.

To increase a wall rigidity (including with openings) it is required to insert metal cores from light formed sections of channel bar type (t- at least 2 mm) or in situ reinforced concrete cores with cross section of 120 x 200 mm in cladding at a distance not exceeding 3 m on the level from the point of flexible fastening in column.

Cores in upper part should have flexible fastening to joist. Besides it is required to provided for concrete reinforcement wire Ǿ3ВрI in horizontal joint of block work, which is fastened together with brickwork to a column with flexible connections in the form of short roll-formed channel from thin-wall sheet (roll-formed channel is shot to column with concrete nail for shooting).

Completely recoverable deformation capacity of block wall enables to perform gapless wall cladding in interfaces with column and joist surfaces. Trial tests of blocks shows that they are deformed when compressed by frame elements without cracking or destruction. This property of the blocks replaces elastic edge isolation and considerably reduces labor intensity of construction operations, as well as does not have a great impact on frame deformation under external loads.

Face surfaces of block walls should have finishing coat in the form of cement rendering, dry plasterboard rendering or other facing plaster, as well as stone surfacing. It is not recommended to use polystyrene concrete works without stone surfacing or coating from outside.

It is well to bear in mind that polystyrene concrete material is highly heat resistant, but vapor-permeable, therefore in the absence of vapor barrier in outer plaster coat there is a possibility of dampening by condensate. Accordingly it is required to provide for vapor barrier in internal wall prior to finishing, and for “breathing” walls we recommend to accept ventilated solution (ventilated face) without vapor barriers as outside finish.

It is permitted to use winterization from PCT on the inner side of walls from brickwork (250 mm) thick with subsequent plastering or brick laying (120 mm) without vapor barrier (effect of aeration of moisture accumulated during cold period with the approach of worm period without substantial moistening of water-resistant face finishing coat).

For ventilated face it is recommended to use a structure from face brick laying of half brick thick with at least 45 mm distance from block work surface. Herewith it is required to fasten brickwork to block work by flexible connections.

It is possible to provide for window and door openings in the walls without framing of lateral edges with the size of separation partition being not less than the standard size, provided for seismic region with regard to brickwork (total deformation modules conform at adequate block strength). Window and door crossbars are secured by concrete nails through bent metal plate. The example of installation is provided in the picture of components and details (see attachment).

PCBTG with dimensions 600 x 400 x 300 mm (produced only by special order of customer) are used as load-bearing walls of one-storey buildings (attic floor is permitted) with rigid construction. The recommended density of blocks is D500 – D600, and the compression strength is within B1.5 – B2.0. (2,16 – 2,9 MPa). It is recommended to use them in composite laying with in-situ reinforced concrete from heavy weight concrete. It is permitted to use composite laying from burnt brick for inside load-bearing and self-bearing walls.

The recommended density for PPCCS is D600. Herewith the polystyrene concrete compression strength is within B1- B2.5. (1,45 – 2,9 MPa). Testing of freely supported slab with a nominal span of 6 m for vertical load of 400 kg/ m2, without regard to own weight and cement screed of 30 mm thick showed 14 mm deflection in the middle of slab without the signs of cracking. Standard limitation for inter-floor construction makes 30 mm at nominal span being 6.0 m.

PPCCS is fabricated on permanent lower corrugated galvanized deck of at least Н57х750х0.7 grade according to technical specifications TU RST UZ 24045-94. Thickness of light concrete part, reinforced at the bottom by three reinforcements, is 200 mm, and at the top of cross-section there is mesh from wire reinforcement Ǿ3ВрI. A slab span is 6 m. When using a deck with cross-section of more than H57 it is permitted by calculation to reduce a slab thickness to 150 mm.

Shapes and dimensions

Polystyrene concrete items for thermal insulation of exterior cladding structures (picture 5).

Блок общий вид ППБ 60х40х6см

Picture 5. PCT for thermal insulation

L=600 mm, B=400 mm, H= 60 mm (100 mm). D150-D300 of M2-M3.5 grade accordingly.

Shapes and dimensions of polystyrene concrete blocks and permissible deviations from nominal dimensions are shown in pictures 6, 7:

 

Блок сбоку и с торца 200х300х500

Picture 6. PCBTG for non-bearing and self-bearing cladding

Блок сбоку и с торца 300х400х600

Picture 7. PCBTG for self-bearing and load-bearing cladding (two storied buildings)

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Picture 8. PPCCS for floor structures and coverage

Completion materials and fastening tools

It is recommended to supply the following materials for erection and arrangement of winterization of structural components complete with PCT and PCBTG:

galvanized wire with cross section from 2 to 6 mm according to standard (GOST 3282-74);

cement adhesive and plastering compositions; primer compositions; filling compositions both on cement and gypsum basis; constructional tapes; U-channels and protective angle sections; beacon profiles; foam insulation and cement glue.

It is required to have the following tools for erection:

Saw with wide blade and big teeth; electric drilling machine with attachment for agitation of mixes; drill attachment for hole making; cord fender (15 m) with lead ball; leveling instrument 1500 mm, straightening tool 2000 mm; rubber hammer; tin snips; plastic tank for mixing of mortar; basket for plaster; putty spattle – trowel, wide putty spattle, putty spattle for inner angles, putty spattle for arris; notched trowel for glueing if ceramic tile and ornamental facers; manual grinder; wide brush; roller; as well as power-actuated fastening tool for shooting of concrete inserts to columns and joists.

Erection procedure

For construction of buildings using any types of  PCT, PCBTG, PPCCS should be carried out on even horizontal and vertical surfaces of foundation (basement, walls, floor structures). In this connection the surface of foundation elements preliminary prepared as required by application of sand-cement mortar of at least 100 grade, and in the event of surface roughness with drops more than 30 mm – by application of mortar with mesh reinforcement. Foundation should be flattened lengthwise and crosswise. Frame buildings should also have even surfaces of columns and joists.

PCT should be fastened to winterized surfaces, fixed in design position with concrete nails with broadened head in the middle. It is provided to arrange galvanized wire on the head for fastening of plaster mesh. As far as four tiles are mounted on cross joint it is required to attach concrete fastening nail in the angle (one concrete nail in the middle of tiles and at all intersections of horizontal and vertical joints).

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Picture 9. PCT fastening

Prior to tile laying the wall surfaces should be covered by glue primer. We recommend to glue polyethylene film (vapor barrier). The length of concrete nail should be 100 and 150 mm according to slab thickness.

During erection of cladding structures, blocks should be mounted with a groove upward. When mounting the blocks with grove upward, joint glue is distributed more evenly in tongue-and-groove space, and saddle joint of lower course block will be cut.

PCBTG are laid on adjacent courses alternatively with displacement of vertical butt welds.

It is required to mark positions of exterior and partition walls on foundation. It is also recommended to mark position of door openings.

Blocks of the first course are mounted and leveled by means of straightening tool and leveling instrument. A beam profile may be mounted along the walls for the sake of convenience. Prior to laying of the first course it is required to apply cement mortar and joint cement glue to foundation, and then tightly press by a block to foundation.

It is required in order to prevent heat leakage between lower part of block and upper part of foundation, as well as for water isolation purposes. When laying subsequent courses, glue (cement or joint glue) is applied to the grooves of the lower course. Besides, glue is also applied to vertical end groove of blocks. It is required to put each laid block in design position by means of a rubber hammer. Excessive glue should be immediately removed and used for subsequent laying. It is required to strive for thickness of vertical and horizontal joints to be 3 mm to a tolerance of ±0.5. It is required ensure that all blocks are in plane in horizontal and vertical direction using straightening tool and leveling instrument.

Non-standard elements are required when laying alternately. PCBTG are easily cut by hand hacksaw with wide blade and big teeth or special electric tool.

Openings for subsequent placement of doors or windows may be left in cladding structures and partitions. It is possible to install wooden, aluminium, steel and plastic door and window frames. If opening dimensions are not big, i.e. not more than 1/4 of cladding structure or partition, and its total area does not exceed 1/10 of total area of cladding structure or partition, then such openings may be cut after structure erection. Big openings are made directly during erection.

The picture of components and details shows an example of laying of one opening of frame for outer spandrel wall from PCBTG. A space between columns of multi-storey frame building with typical center-to-center distance between columns being 6.0 m, floor height of 3.3 m, column section being 400 x 400 mm, joists section being 400 x 400 mm, is accepted as a floor opening. Floor structures and cladding are made from precast profile polystyrene concrete slabs with depth of section being 200 mm and floor thickness being 100 mm.

Composite laying from cladding structures using PCBTG, which combines strength properties of in situ reinforced concrete with high thermal insulation characteristics of polystyrene concrete, is used for construction of detached cottages and low rise (2 floors) public buildings.

In order to improve adhesion it is required to apply primer to all surface by means of roller or brush.

Basic safety rules for execution of work

Cladding structures and partitions from PCBTG and PPCCS should be erected in compliance with the requirements of CMC 3.01.02-00 “Construction safety regulations”.

Persons, who underwent safety and occupational sanitation briefing and trained in erection techniques, shall be permitted to construction of cladding structures and partitions from PCBTG and PPCCS.

It is recommended that erection of structures using PCT, PCBTG and PPCCS is performed by specialized teams, experienced in erection of such structures and equipped with special purpose tools and overalls.

Tools, equipment, accessories and hardware for erection of structures should meet safety requirements to performance of construction and erection works.

Basic rules for technical maintenance of structures

In the course of maintenance of cladding structures and partitions from PCBTG and PPCCS it is required to suspend various items on them. Different fixing devices are used according to weight of suspended items.

Light weight items are fixed to cladding structures and partitions from PCBTG and PPCCS by means of plastic anchor bolts. At the same time it is required to consider maximum permissible load per anchor bolt not exceeding 45 kg.

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