This invention relates to the process for the manufacture of Styrex Rapicon Modules and more particularly to such pre-engineered wall & partition units which shall have the provision for in-built conduit passages inside the modules for cables and also in some cases plumbing lines etc.
Stvrex Rapicon Modules
INTRODUCTION
Various types of Panels and multilayered boards, made from a variety of ingredients, with some specific property characteristics, have been thrown up in the market for use in the building industry. Most of the available varieties have had to compromise on the comprehensive coverage of a wide range of properties desired in the product to suit divergent applications and accompanying environmental factors. For versatility of application and consistency with various environmental and property requirements that become significant while ultimately selecting any of these products, a single product may not optimally provide a solution to satisfy all the different needs. These needs could be related to the surrounding atmosphere with regard to humidity, temperature, ground conditions taking into account seismic activity, fungal exposure, moisture, termites, fire hazards in industrial and commercial applications, wind loads in turbulent atmospheric zones, areas with excessive rainfall and similar aspects along with the customer preferences with regard to color, surface texture, workability on the product chosen. Thus a variety of end use segments is created for the prefabricated building products, wherein different property characteristics have comparatively higher significance.
A review of available options exposes the limited applicability of the different varieties offered in the market. Plywood panels which have been used for quiet some decades, has time and again proven very susceptible to fire hazards, besides being poor in water resistant which gives swollen and aesthetically unappealing appearances leading to periodic repairs, replacements. They are poor sound barriers too.
Resin bonded boards with wood shavings do not have any significant fire retardant property neither much water/ moisture resistance. Boards with core of expanded polymeric plastic substrates are also not robust enough for usual load bearing applications and impact resistance, and are also rather unstable in the case of high temperature impact and do not have any significant fire retardant property. And Gypsum boards are rather fragile for load bearing applications though they have some better sound absorbent property.
Deformation due to the higher flexibility of the softer plastic core and quite often the appearance of the cracks caused by impact on surface on composite boards with such soft core, or discoloring of the joints impairs the visual appeal, especially for the interior applications.
Durability of most of these available panels may not be as much when compared to traditional masonry walls, however it may be argued that these prefabricated panels provide faster erection execution and can be considered for
a wider variety of locations where old traditional method of masonry construction is difficult and time consuming. Moreover interiors generally undergo some change with time, to comply with recent fashionable trends or alterations desired by corporate customers for flexible layout possibilities.
Pre-cast concrete panels are quite heavy and require quite heavy-duty material handling equipment while erecting walls. They are also difficult to work on with conventional hand tools.
The use of asbestos sheet claddings is not considered environmentally friendly with hazardous health implications and very stringent health safety norms.
Generally all panels available require significant labour intensive skilled finishing operations during erection, and any necessary repair work to achieve aesthetically acceptable external cosmetic finish. Moreover they all subscribe to visible external wiring channels on the surface of the walls, which are generally carried out once the wall panels are erected in position to form the wall or partition, resulting in repeated repair work and aesthetically unappealing wiring channels over the surface of the wall.
INVENTION INCENTIVE
The proposed invention incentive of Styrex Rapicon Modules is to provide pre-engineered floor and wall modules, having in-built functional characteristics and easier maneuverability during erection, with varying surface textures for aesthetic looks. It shall also be capable to withstand seismic tremors which become devastating for rigidly homogeneous masonry walls.
It is, with such specific considerations, intended to have a superior lightweight product hitherto unavailable in the market offering a comprehensive range of controlled properties with special reference to the precisely controlled process sequence, operational parameters and ingredient characteristics.
To provide pre-conduited modular units which have been customized for concealed wiring and are critically controlled in quality by programmed logic controlled homogeneous mixing and blending of a specific grade of cement with silicaceous material in precise proportion with provision for in-built conduit passages.
One of the main characteristics of the proposed invention lies in having a well researched operational timings before aerating the mixture which goes to form the core of the light weight Styrex modular units with the option of built in advantage of conduit tracks within the thickness of the module between the cladding sheets, which makes it a unique new product and gives a neat flush wall appearance with only the switch boards visible for operations. The added and very significant advantage is that the modules are manufactured with environment friendly asbestos free cladding sheets.Innovative planning of operation sequences and laying down strictly controlled processing parameters along with careful selection of constituent ingredients, ensures a final product with the visualized property characteristics.
It is with such specific considerations the proposed inventive process has been established to offer a superior lightweight product hitherto unavailable in the market, offering a comprehensive range of properties keeping in view the ever increasing customer demand characteristics, with special reference to the precisely controlled process sequence, operational parameters and ingredients characteristics. These inventive and innovative planned process parameters enables the production of these pre-engineered lightweight Styrex modules with different core property characteristics based on the ingredients composition.
The process involves the homogeneous mixing and blending of a specific grade of finely ground cement (OPC/Gr53) with slurry of silica-rich materials in a pre-estimated proportion followed by the mixing of styropor globules and other constituent ingredients as mentioned hereafter in the process highlights. The constituents follow in a predefined sequence of well researched operational timings before aerating the mixture, which goes to form the core of the lightweight module. This process sequence, unique combination of ingredients and the operational parameters established, is a highlight of the invention procedure being hereby presented. The process parameters are enumerated in the following passages conforming to the established sequence of operations in this invention. The ingredient constituents, besides styropor globules, can include different fibrous additives in the form of cellulose fiber or some man-made fiber in finely expanded fluff and/or even a combination of these additives. With this hitherto unused ingredient contents of styropor globules and cellulose/man-made fiber, along with the option of customised built in conduit passages within the thickness of the modular unit, these Styrex Rapicon Modules become a unique new product. A unique edge profile is also incorporated for versatile adaptability during erection, and it gives a neat flush wall appearance with only the switchboards visible for operation. The cladding material is chosen from environment friendly totally asbestos-free Fiber- Cement sheets or Calcium Silicate sheets.
The precisely controlled procedure with attributed features to the finished module is presented hereafter for process parameter information.
PROCESS FLOW
The solids to water ratio for this complete process is controlled between 32:14 to 32:20. The solids content comprising of the ingredients like Fly-ash, Cement, Lime, Vermiculite, Cellulose fiber and Styropor globules are added in a precisely controlled procedure. The water used in the process is also maintained within a controlled temperature range between 25-40 degrees Celsius.
For the desired quality of blending and mixing of ingredients selected, the process is split into specifically delineated phases for better control on quality achievement in the final composite product. The phased break-up of the blending and mixing operations also makes the process adaptable to different ingredient mixes that can cater to different core compositions and also amenable to customization by including additives to achieve customer desired product characteristics.
For the desired quality of blending and mixing of ingredients selected, the process is split into different phases for precise conformity of ingredient composition in the final composite product. The phased break-up of the blending and mixing operations has been conceived with a view to make the process adaptable to different ingredient mixes that can cater to different core compositions. This also makes the process amenable to be customized to include additives to achieve customer desired product characteristics.
The manufacturing process is broken up into four phases as listed below:--

Phase-l Phase-ll Phase-Ill Phase-IV

Preparation of Core mix. Aeration & Pouring. Moulding & Mould Handling. Curing & Storage.
FIRST PHASE - Preparation of Basic Core mix

A slurry of pulverised silica-rich material like Fly Ash of superfine mesh size in equal proportion with water is prepared and kept under continuous agitation in a holding tank. Pre estimated quantity of finely ground dry OPC/Gr43 Cement and a corresponding measured quantity of the slurry is transferred to a mixer-blender on load cells and blended for a specific period of time to ensure adequate dispersion. A pre determined quantity of Additive-l in powdered form and styropor globules are then added to the mixer-blender and the mix is blended further for some time more. A further addition of cellulosic or man-made synthetic fibre can also be made in this phase, if that is also selected as an ingredient for the core mix. In this first phase 80-85% of the total final water requirement, including the content of water in the slurry, at a controlled temperature is added, depending upon the constituent mix ratio. The cellulose or man-made fibrous content, if it is included as an ingredient, is added in the beginning of the phase along with the slurry, to allow for the water absorption by the cellulose fibers. The cement and other constituents like Styropor and Additive-l follow thereafter. This mixture forms the basic core mix which is further mixed with the aeration additives in precisely controlled batch sizes in the subsequent phase of the core mixing process.
SECOND PHASE - Aeration & Pouring
The basic core mix from the first phase is then taken in a measured batch size to an Aeration Mixer, which is also on load cells and here it is diluted and mixed with the aerating agent in the following sequence.
• 10-15% of the water requirement within the controlled temperature
range is added in the Aeration Mixer before the transfer of the basic
core mix from the first phase mixer-blender.
• A precise quantity of the aerating agent is added to the batch size of
core and blended for only 60-90 seconds. The mix is now finally ready for pouring into moulds and the small aerated casting/pouring batch is pumped to the Pouring Hopper from which they are poured into the stack of multiple moulds of a batch waiting underneath the hopper on bogies. The expansion due to aeration is allowed to take place within the moulds. The hopper is emptied within 2-3 minutes.
THIRD PHASE - Moulding & Mould Handling Preparation of Mould :
The Styrex Rapicon Modules are cast in precisely fabricated moulds that can be stripped after the setting and initial hardening of the core with the cladding sheets and reused for subsequent batches of production. These moulds incorporate a unique mating edge profile and the provision for alignment grooves for vertical mounting assembly of the modular units can also be incorporated.
The provision for concealed conduit passages, if desired within these modules, is provided with precise orientation and alignment within the moulds and the finished module has only to be mounted with the switchboard after drawing the wires through these conduit passages while erecting.
This provision for conduit passages when desired by any customer, incorporated right at the stage of pouring the core mix, gives a finished modular wall unit, ready with in-built conduit tracks for easy and quick wiring by the electrical contractor, thereby giving a neat flat surface and saving the cost of external wiring channels and covers.
In special demand cases, the positioning of the conduit passages can also be customized to some extent, depending upon the volume of requirement, and with adequate advance notice.
Mould Handling on Bogies:
The gang of moulds on bogies wait under the Pouring Hopper, and once the mix is poured, the moulds are immediately closed from the top, clamped and the bogie moved away from under the Pouring Hopper to be taken away to a waiting line where it is left undisturbed for the initial setting and hardening period of 12-16 hours. A new bogie with a gang of empty moulds comes under the hopper.
FOURTH PHASE-Curing & Storage
The curing of the modular units after pouring and testing thereafter forms the longest time segment for the production cycle time for these units. Any compromise in the minimum required timings for setting of the core mix and subsequent curing within moulds can affect the resultant strength characteristics of the final composite product. Special care is taken to ensure adequate moisture retention within the modules while the initial curing takes place, and also after the stripping of the moulds and subsequent stacking of the modules for the final prolonged curing period and hardening of the core. This is ensured by providing for moisture barrier enclosing of the stacks to retard water evaporation and prevent any rapid loss of moisture content.
The setting time and initial curing time is within the cladding cement sheets, held within clamps in the same stationary condition without any disturbance or movement for a minimum stipulated time of at least 9-12 hours. Thereafter the moulds and holding accessories can be stripped from the Styrex Rapicon Modules. 12-14 hours after pouring, the modular units in the moulds are ready to be stacked vertically in curing bays either under shower for water curing, or in the ambient atmosphere with enveloping moisture barrier coverings for air curing, for the final curing period. The careful stripping and gentle handling operations thereafter are very strictly ensured to avoid any loss due to mishandling and breakage.
The modular units, once stripped from the moulds after the initial setting and curing as stated above, are thereafter stacked vertically for the final curing period of around 25 days. This prolonged curing gradually builds up the maximum strength attainable in the core as well as the bonding between the skin sheets and the cement core.
Ensuring stage-wise quality parameters is of high significance, and every stage of operation is closely monitored, followed by interim sample tests with regard to desired property characteristics and documented for future reference and research data. Even a semi-cured modular unit, after the initial setting and curing of 24 hours, is tested at random for strength parameters and density assessment. After the 25 days of either water-spray curing, or atmospheric air curing, final testing of the modular units is done for its structural strength and flexural rigidity besides the final density assessment and other property characteristics such as sound barrier effect, thermal insulation and fire rating tests etc.
PRODUCT CHARACTERISTICS
The general characteristic features of the Styrex modular units can be broadly enumerated below:-
1. Size of modular unit : 0.3Mx0.3M to 3.05Mx0.61M.
2. Thickness ranges of modules : 40 rnm -125 mm
3. Weight per Sq. Mtr : variable from 34-35Kg/M2 to 90-95Kg/M2
4. Composite Density : 0.5 -- 1.2.
5. Flexural Strength : 50 Kg/cm2
6. Max Deflection (span =300mm): 0.9-1.0 mm
7. Water Penetration : Negligible.
8. Linear Expansion : 1.2 mm/Mtr. It is the result of the unique selection of ingredient combination and strict enforcement of process and material quality parameters that these lightweight pre-engineered, modular units stand out as a novel innovative product with desired comprehensive property characteristics for specific interior and industrial applications.
The various aspects of product differentiation which can be enumerated are:
1) LIGHWEIGHT MODULAR UNITS - The Styrex modules are
lighter than other concrete panels considering the composite
resultant density of the aerated core with the styropor globules
and the cladding sheets. These modules are 15-25% lighter than
other cement concrete panels. The density offered can also be
varied to some extent as per customer's requirement regarding
the usage environment and strength requirements vis-a-vis the
lightweight easy handling feature of the panels.
2) EASE OF HANDLING UNIQUE EDGE PROFILE - Keeping in
mind the ease of the erector and speedy assembly of modular
building units, the mating edge details are so designed that the
edges automatically align themselves holding each other. Upside-
down or inside-out, anyway the edges can be made to mate and
flush neatly.
3) CONCEALED WIRING - These modular units can also have
unique in built conduit tracks within the thickness of the cladding
sheets and no external wiring and visible electrical wiring
channels and covers need to be fixed over the surface of the
built-up walls, which stands out as a protrusion on the surface of
the wall, and adversely affect the aesthetic appearance of a clean
flat wall.
4) VERTICAL ASEEMBLY - The modular units can also have the
built in provision for alignment strips in case increasing of the
height of enclosures is required by mounting panels vertically
above another. The same provision can be utilized for holding
and aligning panels for the ceiling wherever so chosen with the
help of fixtures and accessories used for ceiling erection. These
fixtures are also exclusively designed for ease of assembly and
can be made available to the end user.
5) ASBESTOS FREE - The fiber-reinforced cement sheets or the
calcium silicate sheets used for cladding as the skin of the
modular unit are Asbestos-free and hence environment friendly.
As they can be worked upon with general carpentry tools, the
dust of the cladding sheets, generated during sawing/drilling or
similar working, pose no environmental health hazard as
compared to the asbestos-containing similar products and can be
dispensed with as any other domestic dust.
6) PROCESS FLOW DIAGRAM STYREX RAPICON MODULES

Silica-rich matll PFA
mixing into a slurry with equal proportion of water for adequate dispersion.

Mixing of Core ingredients In 2 steps:-
Step-1: Add Cement— during continuous
blending/mixing.
Step-2: Add Additive-I after Cement- mix for
specified time.
Step-3: Add Styropor globules- mix for
specified time.

OPTIONAL Addition of Cellulose or Man-made Synth Fibre just before adding Cement in Step-1

Transfer of Pouring Batch size to Aeration Mixer. Addition of Aeration Agent in the Transferred Batch Size.— blend for specified period. Mix is ready for pouring into moulds.
(Table Removed)
Transfer to Pouring Hopper over Bogie Line.

Bogie under Pouring Station. Ready to receive Pouring Batch Size.

We Claim :
1) Process for the manufacture of Styrex Rapicon Modules comprising the
following steps.
a) High strength finely ground OPC/Gr43 cement and Pulverized Silica-rich material of superfine mesh size is taken in a predetermined ratio and constitute bulk portion of solid content of core mix by weight blended in a blender cum mixer with 0.25%-0.8% by weight of mix of man-made fiber and/or cellulose fiber if also chosen as an ingredient.
• 80%-85% of the total water requirement at 25-50°C is added in
Phasel to facilitate fiber soaking if cellulose fibre is chosen as an
ingredient.
• Cement is added in pre weighed quantity, controlled by a PLC
( Progammable Logic Controller).
• Cement and Silica-rich ingredient is mixed for pre-estimated period,
forming basic core mix and thereafter mixed with other additives like
Styropor globules and Additive-l in controlled batch sizes. The said
core mix is taken to Aeration mixer according to pouring batch size
and blended for a short stipulated period for the aeration agent to
disperse in the mix and make it ready for pouring immediately by the
time the expansion starts.
• Small casting/ pouring batches are pumped into specially fabricated
hoppers and poured into stacks of multiple moulds having unique in
built mating edge profile and provision for alignment grooves for
vertical mounting assembly of these modular wall/floor units, if also
desired. Provision for concealed conduit tracks within the thickness
of the modular units is incorporated in the moulds assembly if
desired in the final product for easy and quick wiring.
• Setting of Core Mix and Curing of the cladded modular units.
2) Process for the manufacture of Styrex Rapicon Modules, as claimed in claim
1 wherein blender is having slow speed below 50 RPM.
3) Process for the manufacture of Styrex Rapicon Modules, as claimed in claim
1 wherein Styropor globules are added as a primary ingredient.
4) Process for the manufacture of Styrex Rapicon Modules, as claimed in claim
1 wherein Silica-rich ingredient is added in slurry form with equal quantity of
water.
5) The product Styrex Rapicon Modules, as claimed in claim 1.
6) Process for the manufacture of Styrex Rapicon Modules as herein described
with examples and flowchart.