The present invention relates to composite cement panel for use in a roof deck or similar structure, and a fabricating method of the cement panel.
The thermal insulating material 118 reduces heat transfer through the concrete roof deck 102 into the building below. The protective cement screed 122 protects the thermal insulating material 118 and the waterproofing membrane 110, and bears the human traffic on the roof deck. Such a construction 100 is constructed in-situ on site, with an expansion joint provided at regular intervals.
Construction 100 suffers from a range of problems. The expansion joints in concrete screed layer 122 are a weak point in the construction and a source of leaks. Residual water becomes lodged between the thermal insulating material 118 and the waterproofing membrane 110 after rain. When exposed to heat from the sun, the water expands and evaporates, exerting pressure on the thermal insulating material 118 which in turn exerts pressure onto the protective screed concrete 122. Both the protective screed concrete 122 and thermal insulating material 118 will generally crack due to such stress, leading to leakage and/or “sickness” in the construction 100.
A further problem is that on site cladding construction makes quality control difficult, can cause damage to the waterproofing system, and is subject to the vagaries of inclement weather during construction leading to time delay. In addition, mixing, handling and/or applying concrete slurry on site can be messy and laborious.
Still further, in the event that maintenance is required to the underlying roof deck 102, waterproofing membrane 110 and/or components of the built-up waterproofing system 104, 118, 120, 122, the protective screed 122 and some or all underlying layers need to be destructively removed such as by being cut away, effectively destroying the construction 100. The entire process of building up the waterproofing system must then be repeated to re-establish a waterproof cladding.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
At step 312 a pre-mixed self-levelling high strength cement grout, with or without concrete hardener or chemical additive, is prepared. At step 306, the cement grout is poured onto foam board 200 and into formwork 2. During this step, cement grout will fill up the round recesses 3 in the formwork 2, the gap between the foam board and the bottom surface 4 of formwork 2, the gap between the periphery of foam board 200 and inner surfaces 214, 215, 216 and 217 of formwork 2, and the holes 202 of the foam board 200. At step 308, the cement grout fills formwork fully, and is trowelled and finished. At step 310 the cement grout is left to dry and harden, hence to form a cement casing 502 encapsulating foam board 200, and form the composite cement panel. At step 314 the formed cement panel is removed from the formwork 2.
Depending the building roof conditions and the finishing requirements, the composite cement panel may be fabricated with a suitable finishing layer on its top surface. For example, at an optional pre-dry finishing step 318, pebbles may be pours onto the top surface of the wet composite cement panel. The pebbles are then attached onto the top surface of the panel, and dried together with the panel. Alternatively, color cement powders may be supplied onto the top surface of the wet composite cement panel and dried together, so as to form a colored finishing layer. Imprints with predetermined patterns may also be formed, by molding or pressing the patterns on the top surface of the composite cement panel. In a further optional after-dry step 320, as an alternative of step 318, the dried composite cement panel may be covered by tiles, wood panels or natural/artificial stones and/or a layer of heat-insulating or waterproof coating.
With reference to
The size and thicknesses of foam boards 200 are kept in appropriate ratio to the size and thickness of the finished cement panel 800 to achieve a satisfactory effect of thermal insulating. In one embodiment, the dimensions of foam board 200 are 18 mm thick by 480 mm width by 480 mm length. Specifications of the one exemplary polystyrene foam board 200 are listed in Table 1 below.
The composition of an exemplary pre-mixed, self-leveling, high strength cement grout is listed in Table 2 below.
The specification of an exemplary concrete strengthener is listed in Table 3 below.
It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.
Number | Date | Country | Kind |
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200703691-6 | May 2007 | SG | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/SG2008/000174 | 5/9/2008 | WO | 00 | 3/15/2010 |