KR20230046348A - Composite slab for reducing interlayer noise - Google Patents

Abstract

The present invention relates to a composite slab for reducing interlayer noise using a high-density cement composite, which may reduce heavyweight floor impact noise without an increase in the overall thickness of a bottom structure by combining a second slab made of the high-density cement composite with an upper part of a first slab, a structure member that delivers an upper weight to a vertical member, for increasing the weight of the slabs. The composite slab for reducing interlayer noise using a high-density cement composite of the present invention for reducing interlayer noise in an apartment house comprises: a first slab on which rebars are spaced in a first cement composite; and a second slab which is placed at an upper part of the first slab as a second cement composite with higher density than the first cement composite. The second cement composite includes a 60 to 70 fine aggregate weight part with 2.9 g/㎤ to 4.0 g/㎤ of density, and a 10 to 40 cement weight part.

Description

Composite slab for reducing interlayer noise using high-density cement composite {Composite slab for reducing interlayer noise}

The present invention can reduce weight impact noise without increasing the overall thickness of the floor structure by synthesizing a second slab composed of a high-density cement composite to increase the weight of the slab on top of the first slab, which is a structural member that transmits the upper load to the vertical member. It is about a composite slab for reducing inter-floor noise using a high-density cement composite that can be used.

Recently, as apartment buildings have become common as residential buildings, noise between floors has emerged as a serious social problem, such as increasing disputes between neighbors due to noise between floors between households.

Floor impact noise that causes inter-floor noise is largely classified into light impact sound caused by light and hard impact and heavy impact sound caused by heavy and soft impact.

Light impact sounds temporarily startle residents, but they do not have reverberation and cause relatively little discomfort, whereas heavy impact sounds tend to leave reverberations and cause severe discomfort and mental pain, which is a particularly big problem in apartment houses.

Weight impact sound, which is a low-frequency impact sound, is a noise transmitted by slab vibration, and is closely related to the dynamic characteristics of the slab due to the thickness, density, stiffness, and support conditions of the slab.

Accordingly, in order to block floor impact sound, the floor thickness is limited to 210 mm or more for wall-type or non-removable plate structures and 150 mm or more for ramen structures. It is regulated to be less than 58dB for impact sound and less than 50dB for heavy impact sound.

These regulations mean that the slab thickness has a great relationship with the floor impact sound, especially the weight impact sound.

However, even if the floor thickness is further increased beyond 210 mm, the impact sound blocking performance effect is very limited.

In addition, when the thickness of the concrete slab is increased to reduce the impact sound, it is difficult to secure a floor height and the amount of concrete increases, which reduces economic feasibility.

On the other hand, in the floor structure of an apartment house, it is common to construct an insulation layer on top of a concrete slab and form a mortar layer for installing heating pipes on top of it (Patent No. 10-0605030, Utility Model Registration No. 20-0321612, etc.) ).

However, this floor structure is helpful in improving insulation performance, but has a limitation in that it is difficult to expect an effect of reducing weight impact noise due to its lightness and low rigidity.

In order to solve the above problems, the present invention synthesizes a second slab for increasing the slab weight on top of the first slab that plays a structural role, thereby providing a high-density cement composite capable of reducing weight impact noise without increasing the overall thickness of the floor structure. It is intended to provide a composite slab for reducing noise between floors.

The present invention according to a preferred embodiment relates to a composite slab for reducing inter-floor noise in an apartment house, comprising: a first slab in which reinforcing bars are placed inside a first cement composite; and a second slab made of a second cement composite having a higher density than the first cement composite and placed on top of the first slab. Composed of, the second cement composite is a synthetic slab for reducing inter-floor noise using a high-density cement composite, characterized in that it comprises 60 to 70 parts by weight of fine aggregate and 10 to 40 parts by weight of cement having a density of 2.9 to 4.0 g / cm 3 provides

According to another preferred embodiment of the present invention, the second cement composite further contains 3 to 15 parts by weight of fine limestone powder as a filler, and the filler uses a high-density cement composite having a powder degree of 4000 to 5000 cm 2 / g. Provided is a composite slab for reducing noise between floors.

According to another preferred embodiment, the present invention provides a synthetic slab for reducing noise between floors using a high-density cement composite, wherein the second cement composite further includes 1 to 5 parts by weight of a lime-gypsum crack reducing material.

The present invention according to another preferred embodiment provides a synthetic slab for reducing noise between floors using a high-density cement composite, characterized in that the second cement composite further contains 0.1 to 2 parts by weight of powdered resin.

The present invention according to another preferred embodiment provides a synthetic slab for reducing noise between floors using a high-density cement composite, characterized in that the second cement composite further contains 0.1 to 0.5 parts by weight of a shrinkage reducing agent.

According to the present invention, by synthesizing a second slab composed of a high-density cement composite to increase the weight of the slab on the top of the first slab, which is a structural member that transmits the upper load to the vertical member, the natural frequency band of the floor structure is moved to the lower side and the weight is lowered. It is possible to provide a composite slab for reducing inter-floor noise capable of reducing impact noise.

Accordingly, since the weight impact sound reduction effect is improved by the second slab, the thickness of the first slab playing a structural role can be minimized. In addition, since it is possible to embed equipment pipes inside the second slab, it is possible to omit a separate floor layer for burying pipes, enabling economical construction without increasing the floor height.

1 is a cross-sectional view showing a composite slab for reducing noise between floors according to the present invention.
Figure 2 is a graph showing the natural frequency of the floor structure and the excitation frequency of the weight impact sound.
Figure 3 is a graph showing the surface moisture content measurement results over time.
Figure 4 is a photograph showing a composite slab for the weight impact sound experiment according to the presence or absence of cracks.
5 is a cross-sectional view showing a divided state of a second slab by drywall;
Fig. 6 is a perspective view showing a composite slab with separators;

Hereinafter, the present invention will be described in detail according to the accompanying drawings and preferred embodiments.

1 is a cross-sectional view showing a composite slab for reducing inter-floor noise of the present invention, FIG. 2 is a graph showing the natural frequency of a floor structure and the excitation frequency of a weight impact sound, and FIG. 3 is a graph showing the surface moisture content measurement result over time.

As shown in FIG. 1, the composite slab for reducing inter-floor noise of the present invention relates to a composite slab (1) for reducing inter-floor noise in an apartment house, a first slab in which reinforcing bars 111 are reinforced inside the first cement composite (11); and a second cement composite having a higher density than the first cement composite, and a second slab 12 poured on top of the first slab 11; The second cement composite is characterized in that it includes 60 to 70 parts by weight of fine aggregate and 10 to 40 parts by weight of cement having a density of 2.9 to 4.0 g / cm 3 .

The present invention synthesizes the second slab 12 for increasing the weight of the slab on top of the first slab 11, which plays a structural role, to reduce the weight impact sound without increasing the overall thickness of the floor structure. to provide a slab.

The composite slab 1 for reducing noise between floors of the present invention is composed of a first slab 11 at the bottom and a second slab 12 at the top.

The first slab 11 is reinforced with reinforcing bars 111 inside the first cement composite.

The first slab 11 is a structural member that transmits an upper load to a vertical member such as a wall or a column, and reinforcing bars 111 are placed therein.

The first cement composite constituting the first slab 11 can be configured by including cement, fine aggregate, and coarse aggregate as binders, and the first slab 11 itself can exert an effect of reducing weight impact sound to some extent.

The second slab 12 is cast on top of the first slab 11.

The second slab 12 is composed of a second cement composite having a higher density than the first cement composite.

Since the natural frequency of the structure is inversely proportional to the square root of the mass, the second slab 12 is formed of a second cement composite having a higher density than the first cement composite, thereby moving the natural frequency band of the floor structure to the lower side, thereby forming a resonance can be prevented.

The second slab 12 does not serve as a structural member supporting a load, but reduces weight impact noise by increasing the mass of the composite slab 1. Therefore, the second cement composite forming the second slab 12 can be composed of only cement and fine aggregate as binders without coarse aggregate.

In the existing floor structure, a separate floor layer must be provided for electrical or equipment piping. Unlike this, since the present invention can embed electrical or facility pipes inside the second slab 12, a separate bottom layer for burying pipes can be omitted.

Accordingly, even if the total thickness of the composite slab 1 is formed to be thicker than the thickness of the existing concrete slab, it can be configured so that the overall floor height does not increase.

Existing concrete slabs are designed to be much thicker than what is actually structurally necessary to reduce weight impact noise. In contrast, in the present invention, since the weight impact sound reduction effect is improved by the high-density second slab 12, the thickness of the lower first slab 11 playing a structural role can be minimized. In this case, as a result, the thickness of the entire floor structure can be reduced, thereby reducing the floor height.

The first slab 11 may be formed to a thickness of 120 to 210 mm and the second slab 12 may be formed to a thickness of 30 to 120 mm in consideration of the size of the load, the area of the floor structure, and the target for reducing weight impact noise. there is.

In addition, the first cement composite constituting the first slab 11 is configured to have a density of 2300 kg / m 3 at the level of general concrete, and the second cement composite constituting the second slab 12 has a density of 2500 to 2700 kg / m 3 It can be configured to have a higher density than the first cement composite by having a density of ㎥.

When the second slab 12 satisfies the unit volume weight in the numerical range, the natural frequency (f ₀ ) band of the floor structure moves to the lower side, as shown in (a) and (b) of FIG. 2 . Accordingly, by preventing the occurrence of resonance, it is possible to reduce the occurrence of inter-floor noise.

In this case, the difference between the peak point frequency of the natural frequency of the composite slab 1 and the peak point frequency of the excitation frequency of the weight impact sound is within the range of 32 to 125 Hz, and the inter-floor noise reduction effect is significant in this range.

[Table 1] below shows the weight impact sound reduction results by increasing the weight of the second slab.

Weight impact sound was measured when the second slab thickness was 30 mm, 40 mm, and 50 mm based on the first slab thickness of 210 mm.

As a result of the measurement, it can be confirmed that as the thickness of the second slab increases, the weight impact sound reduction effect of 2.1 dB, 2.8 dB, and 3.4 dB, respectively, is exerted.

Hz
existing slab composite slab 2nd slab 30mm
(Weight +80kg/㎡) 2nd slab 40mm
(Weight +100kg/㎡) 2nd slab 50mm
(Weight +130kg/㎡) 63 82.6 80.8 80.3 79.8 125 70.4 67.6 66.7 66.0 250 61.9 59.4 58.7 58.1 500 54.7 53.8 53.1 52.4 inverse A value 55.0 52.9 52.2 51.6 reduction (dB) -2.1 -2.8 -3.4

Since the first slab 11 located below the composite slab 1 is cast on the top of the formwork after the formwork is installed, it is not easy to accurately match the smoothness of the top surface due to formwork deflection during casting of the first cement composite.

In this case, when the cushioning material is directly installed on the upper portion of the first slab 11, a closed space is formed under the cushioning material due to the deflection of the first slab 11. Therefore, there is a problem in that the modulus of elasticity increases due to the air trapped in the confined space, and thus the floor impact sound increases.

However, since the second slab 12 is formed by pouring the second cement composite on top of the first slab 11, which is already hardened and has high rigidity, there is no concern about sagging during curing of the second cement composite.

Therefore, if the second cement composite is formed of a material having high fluidity, the smoothness of the upper surface of the composite slab 1 can be adjusted through self-leveling.

That is, when the cushioning material is installed on the upper part of the synthetic slab 1, an increase in floor impact sound can be suppressed by preventing an air layer from being generated in the lower part of the cushioning material.

The second cement composite is preferably configured to have a flow value in the range of 230 to 270 mm.

To this end, the second cement composite may contain a fluidizing agent.

The fluidizing agent is composed of a mixture of a dispersant that serves to improve initial fluidity by dispersing cement particles in the initial stage of the reaction of the cement composite and a retaining agent that serves to maintain fluidity of the initially dispersed cement composite at a weight ratio of 50:50. It can be.

The retaining agent is a polycarboxylate compound, which disperses cement particles after the reaction of the components of the cement composite, thereby suppressing the deterioration of fluidity improved by the initial glidant over time, thereby maintaining the flow.

The fluidizing agent is preferably included in an amount of 0.05 to 0.3 parts by weight based on 100 parts by weight of the second cement composite.

If the amount of the fluidizing agent is less than 0.05 parts by weight, it is difficult to exert an effect of securing fluidity because the content of the fluidizing agent is too small.

When the fluidizing agent is greater than 0.3 parts by weight, a delay in setting may occur. In addition, it is uneconomical because the improvement in high fluidity and flow maintenance performance is insignificant compared to the amount used.

In addition, a thickener may be included in the second cement composite.

In order to maintain material separation stability without impairing the horizontality and workability of the cement composite, a water-soluble polysaccharide polymer and a hydroxyethyl cellulose thickener of suitable molecular weight may be used.

The thickener is preferably included in an amount of 0.01 to 0.2 parts by weight based on 100 parts by weight of the second cement composite.

If the thickener is less than 0.01 part by weight, material separation resistance is poor.

If the thickener exceeds 0.2 parts by weight, the viscosity becomes excessively high, causing problems in mixing or pumping, and may rather inhibit horizontality.

The second cement composite includes 60 to 70 parts by weight of fine aggregate having a density of 2.9 to 4.0 g/cm 3 and 10 to 40 parts by weight of cement.

The second cement composite constituting the second slab 12 is composed of heavy fine aggregate and cement.

The second slab 12 does not serve as a structural member, but is intended to reduce weight impact noise by increasing the weight of the slab, and is configured by mixing only fine aggregates of 5 mm or less without coarse aggregates to enable self-leveling through securing fluidity. can do.

The weight fine aggregate uses an aggregate having a density of 2.9 to 4.0 g/cm 3 among KS-certified aggregates.

The weighted fine aggregate allows the mortar layer to be weighted within the above numerical range to effectively reduce the weight impact sound while exhibiting appropriate strength.

In addition, the weight fine aggregate has a high modulus of elasticity and reduces the amount of shrinkage.

The heavy fine aggregate is wind mill slag (PS Ball, about 3.8 g / cm 3), electric furnace oxidized slag (about 3.6 g / cm 3), copper slag (about 3.5 g / cm 3), soft slag (about 3.5 g / cm 3), ferro At least one of nickel slag (about 3.1 g/cm 3 ) and blast furnace slag (about 2.9 g/cm 3 ) may be included.

When constructing the second slab with the second cement composite, the modulus of elasticity is 9.4E+03MPa when the general fine aggregate is used, but the modulus of elasticity increases by 23% to 1.2E+04MPa when the heavy fine aggregate is used.

Accordingly, the amount of crack generation was measured as 62.9mm/m2 when using normal fine aggregate, while it was measured at 14.9mm/m2 when using heavy fine aggregate, resulting in a crack reduction effect of 76%.

In addition, it takes a long time for the moisture inside the member to dry when using heavy fine aggregate, which has a dense structure due to its high density.

Therefore, as can be seen in the graph showing the surface moisture content measurement result of FIG. 3, when using high density, the internal humidity of the second cement composite can be slowly reduced, and the internal curing is induced to shrink and cracking can be reduced.

As the cement as a binder, a type 1 ordinary Portland cement or the like may be used, and the fineness is preferably 3500 ± 100 cm 2 / g.

The upper surface of the first slab 11 can be roughened.

In order to maximize the weight impact sound reduction effect, it is preferable to firmly attach the second slab 12 to the first slab 11 so that the first slab 11 and the second slab 12 behave as an integrated member. .

To this end, the upper surface of the first slab 11 may be roughened prior to pouring the second cement composite for forming the second slab 12 .

That is, it is possible to secure strong adhesion between the second slab 12 and the first slab 11 by roughening the upper surface of the first slab 11 .

[Table 2] below compares the weight impact sound reduction effect when the first slab and the second slab are separated and integrated. Here, the thickness of the existing slab and the first slab is 210 mm, and the thickness of the second slab is 50 mm.

Hz
existing slab composite slab Separation of the 1st and 2nd slabs
(2nd slab 50mm) 1st and 2nd slab attached
(2nd slab 50mm) 63 82.6 80.6 79.8 125 70.4 67.1 66.0 250 61.9 58.9 58.1 500 54.7 53 52.4 inverse A value 55.0 52.5 51.6 reduction (dB) -2.5 -3.4

By providing an insulating layer (vinyl) between the first slab 11 and the second slab 12, the first slab 11 is more stable than when the first slab 11 and the second slab 12 are completely separated. When the second slab 12 was attached to the top and constructed, it was found that the weight impact sound was reduced by about 0.9 dB.

The roughening of the upper surface of the first slab 11 may be performed after the first slab 11 is cured. In addition, for workability, it is also possible to roughen the upper surface of the first slab 11 using an appropriate tool before the first slab 11 is completely hardened.

In order to improve the integrity of the first slab 11 and the second slab 12, a primer is applied to the upper surface of the first slab 11, and then a second cement composite is poured to form the second slab 12. You may.

Of course, the first slab 11 and the second slab 12 may be integrated only by applying a primer to the upper surface of the first slab 11 without performing a separate roughening treatment.

The second cement composite further includes 3 to 15 parts by weight of fine limestone powder as a filler, and the filler may have a powder degree of 4000 to 5000 cm 2 / g.

In addition to increasing adhesion strength through tight placement, fine limestone powder that serves as a filler may be included to effectively reduce weight impact noise and improve workability by preventing cracks.

The fineness of the fine limestone powder is preferably 4000 to 5000 cm 2 / g so as to have a finer particle size than cement, and the density and fluidity of the second cement composite can be improved by filling the microvoids between the cements in the above numerical range. .

If the fine limestone powder is less than 3 parts by weight, the effect of improving fluidity and increasing tissue compactness is insignificant.

If the fine limestone powder is more than 15 parts by weight, it may cause a problem of reducing surface integrity, and the effect is insignificant compared to the amount used, which is uneconomical.

The second cement composite may further include 1 to 5 parts by weight of a lime-gypsum crack reducing material.

In order to prevent the occurrence of cracks and reduce the gravimetric sound, the second cement composite may include a lime-gypsum crack reducing material.

The lime-gypsum-based crack reducing material may include at least one of limestone, coke, quicklime, and anhydrite.

When using a lime-gypsum-based crack reducing material within the above numerical range, it reacts chemically with water and/or cement components to exhibit initial expansion and long-term drying shrinkage reduction properties, and improves durability by improving the watertightness of the second slab. there is.

In addition, the lime-gypsum-based crack reducing material chemically reacts with the cement component to reduce the initial heat of hydration, and minimizes the generation of cracks due to the initial expansion of the lime component and the long-term expansion of the gypsum component.

If the lime-gypsum-based crack reducing material is less than 1 part by weight, it is difficult to exhibit sufficient expansion performance and watertightness.

If the amount of the lime-gypsum-based crack reducing material exceeds 5 parts by weight, there are problems of overexpansion and lowering of compressive strength.

The second cement composite may further include 0.1 to 2 parts by weight of powdered resin.

Powdered resin may be further included in the second cement composite to be used together with cement to increase the bond strength and ductility of the second slab 12 .

As the powdered resin, vinyl acetate ethylene or vinyl chloride ethylene may be used.

At this time, when the vinyl acetate content is high, flexibility and adhesiveness are increased, and when the ethylene content is high, durability and water resistance are increased.

The powdered resin is a mixture of an ethylene-vinyl acetate copolymer, a styrene-based polymer resin, and an ethylene-olefin copolymer, and increases adhesion and durability.

If the powdered resin is less than 0.1 part by weight, sufficient bonding strength and ductility cannot be exhibited.

If the powdered resin is more than 2 parts by weight, slip resistance, water resistance and adhesive strength are lowered.

The second cement composite may further include 0.1 to 0.5 parts by weight of a shrinkage reducing agent.

A shrinkage reducing agent may be included to prevent cracking by reducing drying shrinkage of the second cement composite.

The shrinkage reducing agent has an organic surfactant and a glycol ether derivative as main components, and reduces shrinkage stress of the second slab 12 in a dry state.

When the shrinkage reducing agent is used in combination with a lime-gypsum-based crack reducing material, the effect of inhibiting crack generation may be further enhanced.

If the amount of the shrinkage reducing agent is less than 0.1 part by weight, it is difficult to exhibit sufficient drying shrinkage reducing effect.

If the amount of the shrinkage reducing agent exceeds 0.5 parts by weight, the unit volume mass decreases and the amount of air greatly increases, resulting in deterioration in workability.

[Experimental Example]

After testing the physical properties of the second slabs of Examples 1 and 2 and Comparative Examples 1 and 2 having the composition ratios shown in [Table 3] below, the results are shown in [Table 4].

The following materials were prepared to prepare mortar compositions and mortar layers according to Examples and Comparative Examples.

For general fine aggregate, washed sand (sea sand) or crushed fine aggregate with a density of 2.6~2.7 g/cm3 and less than 5.0 mm was used.

For the weight fine aggregate, weight fine aggregate of 5.0 mm or less with a density of 3.5 to 3.6 g/cm was used.

As the binder, a type 1 ordinary Portland cement having a density of 3.1 ± 1 g/cm 3 and a powder degree of 3,500 cm 2 /g was used.

As admixture A, fly ash having a density of 2.1 ± 1 g/cm 3 was used.

Admixture B was a high-powder limestone with a density of 2.9±1 g/cm 3 , a powder degree of 4,000 to 5,000 cm 2 /g, and a CaO component of 52% or more.

Admixture C was a lime-gypsum crack reducing material having a density of 2.9 ± 1 g/cm 3 and a powder degree of 2,800 cm 2 / g.

Admixture A was based on a polycarboxylate-based polymer, and had a specific gravity of 0.5 and a pH of 3.5 to 4.5 (1% aqueous solution).

Admixture B was used in combination with a hydroxyethyl cellulose thickener, specific gravity 0.6, pH 6-8 (2% aqueous solution).

Admixture C was a powdered resin, and a resin obtained by mixing an ethylene-vinyl acetate copolymer, a styrene-based polymer resin, and an ethylene-olefin copolymer was used.

Admixture D is a shrinkage reducing agent, which has an organic surfactant and a glycol ether derivative as main components, and has a density of 0.95 g/cm 3 and a viscosity of 200 cps.

division common
fine aggregate weight
fine aggregate binder admixture
A admixture
B admixture
C admixture
A admixture
B admixture
C admixture
D Example 1 - 65.0 20.0 - 13.0 2.0 0.1 0.1 0.5 0.15 Example 2 - 65.0 30.0 - 3.0 2.0 0.1 0.1 0.5 0.2 Comparative Example 1 75.0 - 20.0 3.0 2.0 - - - - Comparative Example 2 65.0 - 30.0 3.0 2.0 0.1 - - -

Compositions were prepared in the weight ratio (unit: parts by weight) as shown in [Table 3].

Examples 1 and 2 are the second cement composites according to the present invention, which are prepared by adjusting the composition ratio using weight aggregate.

Comparative Example 1 is a conventional general floor dry mortar composition, prepared by mixing powder and sand in a weight ratio of 1:3 and using fly ash as a filler.

Comparative Example 2 is a high-strength dry cement mortar composition containing an increased amount of binder and a fluidizing agent compared to Comparative Example 1.

[Table 4] shows the results of comparing the physical properties of the second cement composite prepared by changing the level of addition range suggested in Examples 1 and 2 to which the present invention was applied and the physical properties of Comparative Examples 1 and 2.

Specifically, the flow is to measure workability, and after filling the flow cone with a top diameter of 70 mm, a bottom diameter of 100 mm, and a height of 50 mm specified in KS L 5111 with the second cement composite, the flow cone is not compacted. was lifted to measure the flow.

Unit volume weight was measured according to the KS L 5220 method, but by measuring the weight by filling a mortar layer in a 1L container.

The adhesion strength is to measure the adhesion performance of the second cement composite. After placing a 5 cm × 5 cm × 3 cm square mold on the prepared concrete surface and evenly filling the kneaded mortar, the temperature is 23 ± 2 ° C, humidity It is cured for 28 days in a space of 60±5%. In addition, a 5 cm × 5 cm square jig was attached to the surface of the specimen using an adhesive, and then tensioned with a tensile tester to measure the adhesion strength.

The compressive strength follows the KS L ISO 679 method, but immediately after molding, the test specimen is stored in a damp box with a temperature of 20±2℃ and a relative humidity of 90% or higher for 48 hours, then the mold is removed, and then stored in a damp box for 5 days. Until the day, it was measured in a laboratory with a temperature of 20 ± 2 ° C and a relative humidity of 65 ± 5%.

The drying shrinkage rate was determined by filling a mold of 40 mm × 40 mm × 160 mm with the second cement composite mixed with water, leaving it for 24 hours in a saturated humidity state at a temperature of 20 ± 2 ° C, demolding it, and then using a micrometer gauge to determine the initial shrinkage rate. The length was measured, and after curing for 28 days at a standard temperature of 20 ± 2 ° C and a humidity of 65 ± 5%, the final length of the mortar was measured, and the shrinkage length change rate of the mortar was calculated as a percentage.

Moisture content was measured after curing for 28 days in a space with a temperature of 23 ± 2 ° C and a humidity of 60 ± 5% by making a mortar test body in an acrylic mold of 30 cm × 30 cm × 5 cm.

division
mixed quantity
(%)
flow
(mm) unit volume mass
(kg/m3) condensation time
(minute) adhesion strength
(MPa, 28 days) compressive strength
(MPa) dry
Shrink(%,
28 days) moisture content
(%,
28 days) first resolution closing primer
uncoated primer
apply 7 days 28 days Example 1 16.0 235 2.510 320 500 2.55 3.21 16.2 23.7 -0.012 8.3 Example 2 16.5 230 2.535 260 440 2.91 3.58 25.1 35.8 -0.021 8.7 Comparative Example 1 19.5 210 2.120 420 620 1.56 - 8.2 14.3 -0.033 4.7 Comparative Example 2 17.5 220 2.155 380 540 1.77 - 20.6 30.8 -0.047 5.5

Looking at [Table 4], it can be seen that Examples 1 and 2 have higher flow and workability compared to Comparative Examples 1 and 2, and have high weight and high rigidity performance through comparison of unit volume mass and compressive strength.

In addition, as a result of the length change rate experiment, Examples 1 and 2 showed a very stable shrinkage rate compared to Comparative Examples 1 and 2. This is because the moisture content was stably reduced due to the high water retention and dense structure compared to Comparative Examples 1 and 2, and the initial expansion due to the use of a lime-gypsum crack reducing material and the shrinkage compensation due to the use of a shrinkage reducing agent were made.

In addition, as a result of the adhesion strength test, Examples 1 and 2 exhibited 1.5 times or more adhesion performance compared to Comparative Examples 1 and 2 due to the addition of a large amount of powdered resin. In particular, the results of the experiment after applying the primer to the lower concrete surface maintained about twice the level of the comparative example.

In the case of setting time, the setting time was shortened compared to Comparative Examples 1 and 2 to improve workability, and by maintaining a fast setting time, the problem of settlement that may occur during large-scale casting with a low casting thickness (30 mm) was solved and compared. It can be seen that there is an effect of reducing the construction period compared to Examples 1 and 2.

FIG. 4 is a photograph showing a composite slab for a weight impact sound test according to the presence or absence of cracks, and FIG. 5 is a cross-sectional view showing a divided state of a second slab by drywall.

As shown in FIG. 5 , a dry wall 2 is installed above the first slab 11 to divide the second slab 12 .

When a crack occurs in the second slab 12, the weight impact sound tends to increase.

In addition, when a crack occurs in the second slab 12, the integrity of the first slab 11 and the second slab 12 is deteriorated, which adversely affects the weight impact sound.

As a result of comparing the weight impact sound when the second slab 12 has a crack (FIG. 4(a)) and when there is no crack (FIG. 4(b)), the second slab 12 has a crack It was confirmed that the weight impact sound was reduced by 2.5 dB in the absence.

Therefore, it is desirable to minimize the occurrence of cracks in the second slab 12 in order to reduce weight impact noise.

To this end, as shown in FIG. 5 , the second slab 12 may be divided in plan by using the drywall 2 installed on the upper part of the floor structure.

Since the length of the second slab 12 is divided by the drywall 2 and the length is shortened, the amount of shrinkage for each section of the second slab 12 is reduced (the shrinkage rate is the same) to reduce cracking and the first slab 11 It is possible to further secure the adhesion performance with the

Fig. 6 is a perspective view showing a composite slab with separators;

As shown in FIG. 6 , the second slab 12 may be divided by a separator 4.

In order to reduce cracking of the second slab 12, the second slab 12 can be divided into appropriate areas by arranging a plurality of separators 4 on the top of the first slab 11 in the longitudinal and/or transverse directions. can

The separator 4 is formed at the same height as the height of the second slab 12, and preferably has a width of about 70 to 200 mm.

When a material having a buffering effect such as PE is used as the separator 4, the maximum sound pressure level due to the centralized impact load can be reduced by distributing the floor impact load.

1: composite slab
11: first slab
111: rebar
12: second slab
2: drywall
4: Separator

Claims (5)

It relates to a composite slab (1) for reducing noise between floors in an apartment house,
A first slab 11 in which reinforcing bars 111 are reinforced inside the first cement composite; and
A second cement composite having a higher density than the first cement composite, and a second slab (12) poured on top of the first slab (11); composed of,
The second cement composite is a synthetic slab for reducing noise between floors using a high-density cement composite, characterized in that it comprises 60 to 70 parts by weight of fine aggregate having a density of 2.9 to 4.0 g / cm 3 and 10 to 40 parts by weight of cement.
In paragraph 1,
The second cement composite further contains 3 to 15 parts by weight of fine limestone powder as a filler, and the filler has a powder degree of 4000 to 5000 cm 2 / g. Synthetic slab for reducing noise between floors using a high-density cement composite.
In paragraph 1,
The second cement composite is a composite slab for reducing noise between floors using a high-density cement composite, characterized in that it further contains 1 to 5 parts by weight of a lime plaster-based crack reducing material.
In paragraph 1,
The second cement composite is a composite slab for reducing noise between floors using a high-density cement composite, characterized in that it further contains 0.1 to 2 parts by weight of powdered resin.
In paragraph 1,
The second cement composite is a composite slab for reducing noise between floors using a high-density cement composite, characterized in that it further contains 0.1 to 0.5 parts by weight of a shrinkage reducing agent.

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