Abstract:
The present invention relates to a method for installing a crack inducing expansion joint filler when placing concrete so as to reduce cracks generated during concrete construction, and an apparatus therefor and, more particularly, to a method for installing a concrete crack inducing expansion joint filler and an apparatus therefor which can vertically install and fix a plurality of fixed rod shafts on a bottom surface, place concrete, and then fit connection means to the fixed rod shafts while connecting and installing a joint filler member, having a cover means which can be attached and detached between the connection means, before the concrete is cured. Thus, since it is possible to install the joint filler member at the same time as placing the concrete on the bottom surface the method and apparatus can significantly reduce the concrete construction period and also cause that cracks generated by the joint filler during concrete curing can be reduced to a minimum, thereby increasing concrete durability and enhancing construction efficiency.

Description:
TECHNICAL HELD 
     The present invention relates to a method for installing a crack inducing expansion joint filler when placing concrete so as to reduce cracks generated during concrete construction, and an apparatus therefor and, more particularly, to a method for installing a concrete crack inducing expansion joint filler and an apparatus therefor which can vertically install and fix a plurality of fixed rod shafts on a bottom surface, place concrete, and then fit connecting means to the fixed rod shafts while connecting and installing a joint filler member, having a cover means (expansion joint filler marker) which can be attached and detached between the connecting means, before the concrete is cured. Thus, since it is possible to install the joint filler member at the same time as placing the concrete on the bottom surface, the method and apparatus can significantly reduce the concrete construction period and also cause that cracks generated by the joint filler during concrete curing can be reduced to a minimum, thereby increasing concrete durability and enhancing construction efficiency. 
     DISCUSSION OF RELATED ART 
     Generally, concrete is primarily used to pave the rooftop slave of apartment complexes or other various buildings, roads, ground, or underground parking lots, train station platforms, or subway roadbeds. 
     In the case of construction using concrete, which is a mix of cement, sand, gravel, and water, water evaporates from in the concrete while the concrete is cured, leaving gaps in the concrete. Such gaps repeatedly expand or contract due to heat in the air, causing cracks in the concrete. 
     Water may flow in the cracks, negatively affecting the building. 
     Thus, there is considered a method for constantly inducing cracks in the concrete in light that cracks are created in proportion to the area of installation of concrete in order to prevent or suppress such cracks. 
     For structural safety purposes by inducing cracks in the concrete, upon concrete construction, expansion joint fillers may be put at constant intervals or the concrete surface may be cut horizontally and vertically using a wet cutting machine or dry cutting machine. 
     Conventional expansion joint fillers absorb the expansion and contraction of concrete as the external air varies in temperature so that cracks by the expansion and contraction of concrete may be constantly induced along the expansion joint fillers, thus preventing durability of concrete from weakening due to water leakage by unpredicted cracks. 
     Such conventional expansion joint fillers are configured and installed in various forms. 
     Representative expansion joint fillers are disclosed in Korean Patent No. 10-0542380 titled “expansion joint filler structure for concrete slab and method for constructing the same” and Korean Patent No. 10-0385130 titled “expansion joint filler for concrete slab.” 
     The “expansion joint filler structure for concrete slab and method for constructing the same” disclosed in Korean Patent No. 10-0542380 is described below. 
     A concrete slab expansion joint filler structure for protecting a rooftop waterproof layer of a building includes thermal insulator expansion joint fillers  200  arranged in a grid on the waterproof layer  120 ; pressing concrete  130  poured and cured along with a wire mesh  132  on the thermal insulator expansion joint fillers  200  and the waterproof layer  120 ; a backup material  150  inserted into a cutting portion  220  obtained by cutting the pressing concrete  130  on the thermal insulator expansion joint fillers  200  after the pressing concrete  130  is cured; and a sealant  160  provided on the backup material  150 . 
     Further, the invention provides a method for constructing concrete slab expansion joint fillers for protecting a rooftop waterproof layer of a building, comprising the steps of (a) arranging thermal insulator expansion joint fillers  200  in a grid on the waterproof layer  120 ; (b) placing a wire mesh  132  on the thermal insulator expansion joint fillers  200  and the waterproof layer  120 ; (c) pouring and curing pressing concrete.  130  on the thermal insulator expansion joint fillers  200  and the waterproof layer  120 ; (d) cutting the pressing concrete  130  on the thermal insulator expansion joint fillers  200  after the pressing concrete  130  is cured to form a cutting portion  220 ; (e) inserting a backup material  150  into the cutting portion  220 ; and (f) putting a sealant  160  on the backup material  150  to finish off. 
     This is related to an expansion joint filler structure for concrete slab and construction method which installs thermal insulator expansion joint fillers on a waterproof layer, pours and cures pressing concrete, and then cuts a portion of the pressing concrete on the thermal insulator expansion joint fillers, and inserts a backup material and sealant into the cutting portion. 
     PRIOR TECHNICAL DOCUMENTS 
     Patent Documents 
     (Patent Document 1) KR 10-0385130 published on May 12, 2003. 
     (Patent Document 2) KR 10-0542380 published on Jan. 3, 2006. 
     (Patent Document 3) KR 20-0129425 published on Aug. 19, 1998. 
     SUMMARY 
     However, the conventional “expansion joint filler for concrete slab” has such structure that a connecting member is installed in a supporting member provided in a support, and a shock-absorbing part consisting of a supporting mechanism and a spring is provided in the connecting member to respond to the expansion and contraction of concrete, thereby preventing cracks in the concrete. Such structure is complicated and high in manufacturing costs, rendering itself uneconomical. 
     Further, since the conventional expansion joint filler is installed by the method of pouring concrete after the joint fillers are placed and fastened to the bottom surface, the joint fillers may be relocated or buried by pouring concrete. 
     Further, the conventional expansion joint filler should be installed on the bottom surface before pouring concrete, which requires more labor and costs, resulting in an increased construction time. 
     The present invention has been conceived to address the above issues. 
     An object is to provide a method for installing concrete crack inducing expansion joint fillers and expansion joint filler apparatus allowing an expansion joint filler apparatus including a plurality of fixed rod shafts installed and fixed at constant intervals on a bottom surface where concrete is placed, connecting means fitted and fastened to the fixed rod shafts, and an expansion joint filler member detachably installed between the connecting means to be configured to be installed before the concrete is cured, so that the expansion joint filler member may be installed simultaneously with placing the concrete on the bottom surface, thus significantly reducing the concrete construction period and allowing the expansion joint filler member to minimize cracks occurring when the concrete is cured, thereby leading to enhanced concrete durability and construction efficiency. 
     To achieve the above object, according to the present invention, an expansion joint filler apparatus installed on a bottom surface where concrete is placed to induce a crack comprises a plurality of fixed rod shafts each including a plate fixed to the bottom surface and a rod shaft vertically provided and fixed to an upper surface of the plate joint members each including a fitting installation pipe fitted and fastened to a corresponding one of the fixed rod shafts and multiple wing plates along a circumferential surface of the fitting installation pipe, and an expansion joint filler member fitted into the wing plates to connect and fasten the joint members. 
     According to the present invention, a method for installing an expansion joint filler apparatus installed on a bottom surface where concrete is placed to induce a crack comprises fixing a plate on the bottom surface by way of an adhering means while installing and fixedly arranging fixed rod shafts, placing the concrete on the bottom surface where the fixed rod shafts are arranged, fitting and fastening joint members to the fixed rod shafts when the concrete is in a mortar form before cured, and installing an expansion joint filler member between the joint members while pushing the expansion joint filler member so that a lower support of the expansion joint filler member is inserted into a space portion formed between a front plate and a rear plate of the joint members while the concrete is in the mortar form before cured. 
     According to the present invention, in the method for installing concrete crack inducing expansion joint fillers and apparatus therefor, the rod shafts are fastened at constant intervals to the bottom surface where the concrete is placed, and the concrete is then placed, and before the concrete is cured, the expansion joint filler member may be installed. Thus, the concrete construction period may be remarkably reduced, leading to low-cost construction and economy. 
     Further, according to the present invention, the connecting means are fitted over the rod shafts fixedly installed to the bottom surface, and the expansion joint filler member may be fittingly installed to the connecting means, allowing for simplified installation of the expansion joint filler member. 
     Further, according to the present invention, the expansion joint filler member is hollow to absorb the expansion and contraction of concrete, preventing the concrete from cracking while allowing for simple, low-price manufacture. 
     Further, according to the present invention, the connecting means for connecting and installing the expansion joint filler member may be formed in various shapes, such as a rectangular, triangular, or T shape, allowing for quick response to the environment of the bottom surface where the expansion joint filler member is constructed. Further, a color may be applied to the upper surface of the expansion joint filler member, allowing the bottom surface various decorations. 
     Further, according to the present invention, the upper portion of the expansion joint filler member is configured as a detachable expansion joint filler cover (marker). Thus, the expansion joint filler cover may be removed as necessary, and a sealing means, such as silicone, may be applied, providing for significantly enhanced sealing efficiency. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are perspective views illustrating a concrete crack inducing expansion joint filler apparatus according to the present invention; 
         FIG. 3  is an exploded perspective view schematically illustrating a concrete crack inducing expansion joint filler apparatus according to the present invention; 
         FIG. 4  is a cross-sectional view illustrating an example in which concrete is poured with a concrete crack inducing expansion joint filler apparatus installed, according to the present invention; 
         FIG. 5  is a view schematically illustrating a main part of a concrete crack inducing expansion joint filler apparatus according to the present invention; and 
         FIG. 6  is a view schematically illustrating various examples of a connecting means of a concrete crack inducing expansion joint filler apparatus according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention are described with reference to the accompanying drawings to be easily practiced by one of ordinary skill in the art. 
     According to the present invention, as shown in  FIGS. 1 to 5 , a concrete crack inducing expansion joint filler apparatus  100  includes a plurality of fixed rod shafts  110  fixed and installed at predetermined intervals on a bottom surface where concrete is poured and placed, joint members  120  including fitting installation pipes  121  fitted and fastened to the fixed rod shafts  110  and multiple wing plates  122  provided along circumferential surfaces of the fitting installation pipes  121 , and expansion joint filler members  130  fitted into the wing plates  122  of the joint members  120  and connecting and fastening the joint members  120 . 
     In such construction that concrete is poured on a broad bottom surface, such as an underground or above-ground parking lot or rooftop to securely maintain the bottom surface, water evaporates as the concrete is cured, causing cracks to irregularly occur in the cured concrete bottom surface. To prevent this, concrete is poured, with expansion joint fillers installed to induce cracks during concrete construction. 
     Accordingly, the concrete crack inducing expansion joint filler apparatus  100  according to the present invention is installed on the bottom surface to prevent cracks from occurring upon concrete construction. 
     Here, the fixed rod shafts  110  each include a plate  111  fixed to the bottom surface and a rod shaft  112  vertically installed and fixed to the top of the plate  111 . 
     Thus, the plate  111  is fixedly installed on the bottom surface of the constructed building using an adhering means, such as mortar or a glue or adhesive. 
     Then, the rod shaft  112  provided on the top of the plate  111  may be installed and fastened perpendicular to the bottom surface. 
     The rod shaft  112  may be formed in a multi-part, telescopic antenna structure that may expand or contract so that its length is adjustable. 
     Accordingly, the rod shaft  112  may be rendered to expand or contract in length depending on the thickness of concrete placed on the bottom surface of the building. 
     The wing plates  122  of the joint member  120  include a pair of front plate  122   a  and rear plate  122   b  and a space portion  122   c  spacing the front plate  122   a  and the rear plate  122   b  apart from each other. A side surface portion of the wing plates  122  is connected to the fitting installation pipe  121  to be closed, and the other side surface portion thereof is open. 
     A plurality of wing plates  122  are provided along the circumferential surface of the fitting installation pipe  121 , and the angle between the wing plates  122  may be 90 degrees so that the joint member  120  is shaped as a rectangle, or the angle between the wing plates  122  may be 120 degrees so that the joint member  120  is shaped as a triangle. 
     As such, the joint member  120  may have various shapes, such as a rectangular shape, triangular shape, T shape, Y shape, or L shape, by adjusting the number and angle of the wing plates  122 . 
     The expansion joint filler member  130  may be formed of an elastic material, such as PVC. The expansion joint filler member  130  includes a hollow lower support  131  having both ends each of which may be inserted into the space portion  122   c  between the front plate  122   a  and the rear plate  122   b , an inverted trapezoidal, hollow upper head  132  formed to continuously communicate with an upper end of the lower support  131  to prevent the lower support  131  from sliding down along the space portion  122   c , and an inverted trapezoidal expansion joint filler marker  133  detachably fitted into the upper head  132 . 
     Protrusions  132   a  projecting upwards and having ends bent inwards are formed at two opposite side edges of an upper portion of the upper head  132 , and an upper surface of the upper head  132  forms grooves  132   b  by the protrusions  132   a.    
     Fitting grooves  133   a  are formed in side edges of a lower portion of the expansion joint filler marker  133  to allow the protrusions  132   a  to be fitted and supported. 
     Thus, as the protrusions  132   a  are fitted along the fitting grooves  133   a , the expansion joint filler marker  133  may be positioned and fastened to the upper head  132 . 
     Further, in the expansion joint filler member  130  according to the present invention, as the expansion joint filler marker  133  is pulled upwards from a side surface, with the expansion joint filler marker  133  is fitted to the upper head  132 , the protrusions  132   a  may be elastically deformed to be escaped from the fitting grooves  133   a . Thus, the expansion joint filler marker  133  may be easily attached or detached from the upper head  132 . 
     In case a gap occurs between the side surface of the embodiment marker  133  and the concrete due to the contraction of the concrete when the concrete is cured, the expansion joint filler marker  133  may be replaced with another expansion joint filler marker as large as the size of the gap to fill the gap, or a sealing means may be applied to the grooves  132   b  formed on the upper surface of the upper head  132 , with the expansion joint filler marker  133  removed, thereby preventing the influx of, e.g., moisture. 
     Further, wing protrusions  131   a  are formed on both side portions of the lower support  131  constituting the expansion joint filler member  130  to prevent the concrete from pushing up the expansion joint filler member  130  as the concrete contracts when it is placed in the concrete. 
     Further, the lower end of the lower support  131  of the expansion joint filler member  130  is formed as an inserting portion  131   b  with a cone-shaped sharp tip allowing it to be easily placed in the concrete before the concrete is cured. 
     A method for installing the concrete crack inducing expansion joint filler apparatus  100  configured as above, according to the present invention, is described below. 
     First, multiple fixed rod shafts  110  are arranged and fastened to the bottom surface where concrete is to be poured at constant intervals using an adhering means, such as mortar or adhesive (the step of adhering and fastening the fixed rod shafts  110  to the bottom surface). 
     At this time, since the plates  111  have a large area, it may be easily attached to the bottom surface by way of the adhering means. Further, the rod shaft  112  is installed to expand or contract fitting the thickness of the thickness of the concrete placed. 
     In this case, the position where the fixed rod shafts  110  are to be fixed is previously designed and marked. 
     Subsequently, concrete is poured and placed on the bottom surface (the step of placing concrete). 
     At this time, as the fixed rod shafts  110  are soaked in the concrete, only the rod shafts  112  are shown. Here, the fixed rod shafts  110  may be adjusted to expand fitting the thickness of the placed concrete. 
     The joint members  120  are fitted and installed to the rod shafts  112  when the concrete remains mortar before cured (the step of fitting and fixing the joint members  120  to the fixed rod shafts  110  in the concrete of the mortar form). 
     At this time, since the concrete is placed on the bottom surface, only the rod shafts  112  are shown, but the plates  111  are not. Thus, the joint members  120  may be simply installed to the fixed rod shafts  110  by fitting the fitting installation pipes  121  over the rod shafts  112 . 
     Then, when the concrete remains in the form of mortar before cured, the expansion joint is filler member  130  is pressed down between the joint members  120  so that the lower support  131  is fitted into the space portion  122   c  between the front plate  122   a  and the rear plate  122   b  (the step of coupling the expansion joint filler member  130  between the joint member  120  and its neighboring joint member  120  in the concrete of mortar form). 
     Here, the lower support  131  may be easily installed because the inserting portion  131   b  formed at the lower tip of the lower support  131  is pressed down into the mortar-form concrete. 
     In such case, even when the concrete contracts while cured, the expansion joint filler member  130  is prevented from being pushed up by the wing protrusions  131   a  formed on both side surfaces of the lower support  131 . 
     Further, at this time, the expansion joint filler member  130  is pushed down while tapped, so that the upper surface of the expansion joint filler marker  133  is on the same level as the concrete surface. 
     As the concrete is cured, the bottom surface construction is complete (the step of curing concrete). 
     The concrete contracts as cured on the bottom surface. At this time, even when the expansion joint filler member  130  is pressurized by the contracting concrete, cracks may be prevented from occurring or induced because the expansion joint filler member  130  is formed of an elastic material and includes a space absorbing the contracting force of the concrete. 
     Further, as the concrete contracts, gaps may occur in the outer surface of the expansion joint filler marker  133  of the expansion joint filler member  130 . In this case, the expansion joint filler marker  133  may be pulled up, removed, and replaced with a larger expansion joint liner marker to remove (fill) the gaps. 
     By doing so, the gaps created by the expansion joint filler member  130  may be filled, preventing influx of moisture into the inside of the concrete. 
     Further, as necessary, the expansion joint filler marker  133  may be pulled up and removed, and a sealing member, such as silicone, may be applied for sealing to the grooves  132   b  formed on the upper surface of the upper head  132 . 
     Further, according to the present invention, various colors or shapes may be applied to the expansion joint filler marker  133  to show a diversity of colors or shapes, decorating the bottom surface. 
     As described above, according to the method for installing concrete crack inducing expansion joint fillers and expansion joint filler apparatus allowing an expansion joint filler apparatus including a plurality of fixed rod shafts installed and fixed at constant intervals on a bottom surface where concrete is placed, connecting means fitted and fastened to the fixed rod shafts, and an expansion joint filler member detachably installed between the connecting means to be configured to be installed before the concrete is cured, so that the expansion joint filler member may be installed simultaneously with placing the concrete on the bottom surface, thus significantly reducing the concrete construction period and allowing the expansion joint filler member to minimize cracks occurring when the concrete is cured, thereby leading to enhanced concrete durability and construction efficiency.