KR20040100202A - Concrete Composition for Lightweight and Sound Absorber and Method of Making The Same - Google Patents

Abstract

PURPOSE: Provided is a manufacturing method of porous and lightweight concrete excellent in strength, durability, water resistance and sound insulation by natural curing instead of conventional autoclave curing. CONSTITUTION: A soundproof and lightweight concrete mortar is obtained by mixing 60-75wt.% of cement composition obtained by mixing ordinary cement and rapid set cement in a ratio of 80-30 : 20-70, 1-5wt.% of waste fiber, and 15-30wt.% of expanded pearlite whose surface is modified with 5-15wt.%(based on expanded pearlite) of alkaline silicate solution having a molar ratio SiO2/M2O of 3.5-5.8 to improve resistance against water, weather, corrosion and abrasion, followed by adding 0.1-0.5wt.% of foaming agent such as sodium dodecylbenzene sulfonate, 3-10wt.% of polymer modifier such as non-ionic carboxylated styrene copolymer emulsion, and water to be a water/cement ratio of 0.45-0.65, wherein expanded pearlite is substituted by expanded vermiculite or wood chips. The sound insulating panels are manufactured by pouring prepared mortar into a plate-shaped mold, vibration pressing, and drying at room temperature(0-40deg.C).

Description

Concrete Composition for Lightweight and Sound Absorber and Method of Making The Same}

Glass fiber or rock wool, which is currently used as insulation, insulation and sound absorbing material, generates a large amount of dust during demolition and collapse, generates respiratory diseases and carcinogens that are harmful to the human body, and regulates its use worldwide. Floor noise and vibration in apartments are becoming a social problem. Therefore, the sound absorbing and insulating walls used in homes, roads, and factory areas require the development of new materials and thus the present invention.

The present invention is an inorganic porous lightweight concrete sound absorbing material having a large number of continuous and independent pores, good strength, heat insulation, water resistance, heat resistance and sound insulation and excellent productivity, and suppresses noise generated in railways, roads, and factories. The present invention relates to a method for producing a new lightweight sound-absorbing concrete composition and composite plate to improve sound insulation and sound absorption performance of soundproof walls and buildings.

Representative lightweight concrete secondary products used as conventional sound absorbing materials are ALC materials manufactured by curing by steam curing or steam at high temperature and high pressure by adding foaming agent to cement, lime and siliceous fine powder. The company has not received much attention until now due to rising production costs. As related technologies, Korean Patent Laid-Open Publication No. 2002-003053, "Method of manufacturing sound absorbing and insulating material using light foamed concrete", "Sound absorbing soundproof panel using light foamed concrete" of No. 2000-060707 and "Concrete of No. 1996-00800" Manufacturing method of sound absorbing material "and Japanese Patent Application Laid-Open No. 53-88024, and 58-187305. These manufacturing methods are made by mixing foaming agent and water in the raw material of concrete to generate bubbles, curing them first, and then using autoclave. As a method of performing high temperature and high pressure curing, there are many disadvantages in terms of manufacturing equipment and production cost.

The present invention is to identify the composition of the light-weight sound-absorbing concrete having a predetermined strength and all physical properties and a method of manufacturing the same without the high temperature and high pressure curing as described above. In order to utilize as a sound absorbing and insulating material of a factory, which has a high occurrence, it should be excellent in surface hardness, strength, heat insulation, and durability in addition to the sound absorbing and insulating property.

Therefore, the present invention can satisfy the above various conditions, that is, the apparent specific gravity is 0.5 ~ 0.7, the compressive strength is about 40㎏ / ㎠ or more, the bending strength is more than 10㎏ / ㎠ and the average sound absorption is about 0.5 ~ 0.8 and the water resistance and durability It is intended to achieve the technical problem of the present invention by presenting a composition of the composite plate and a method of manufacturing the same.

Lightweight concrete sound absorbing material of the present invention is a composition of the hydraulic binder is tricalcium aluminate (3CaO 5Al ₂ O ₃ ), tricalcium silicate (3CaOSiO ₂ ), calcium aluminate sulfate (4CaO 3Al ₂ O ₃ · SO ₃ ) And a mixture of fast and high strength special cements composed of calcium, iron and magnesium silicates ((Ca · Fe · Mg) SiO ₃ ) and ordinary portland cement, as well as light weight aggregates and sound absorbing materials. And it is intended to manufacture a light-weight concrete sound-absorbing material panel using a waste fiber as a mixed material and adding water to a material mixed with a foaming agent, waterproofing agent, antifouling agent and the like.

Foamed pearlite, used as light weight aggregate and sound absorbing material, is a porous material in a continuous pore state, so it has good sound absorbing properties, but it has high absorbency and water permeability, so it is waterproof and water repellent from external moisture when used as a sound absorbing material mixed with composite materials. This is the biggest problem.

Therefore, in the present invention, the expanded pearlite was developed to have a surface structure having waterproof water repellent and continuous pores. In other words, water and metal salts are spray-dried on the surface of the pearlite particles, in particular colloidal silica, in which water and metal salts have a molar ratio (SiO ₂ / M ₂ O, M = K, Na, Li) of 3.5 to 5.8. A surface modified pearlite sound absorbing material coated with a material was developed.

The sound absorbing panel described above can adjust the specific gravity or strength according to the purpose and is not limited to the type and amount of admixtures and other additives.

The hydraulic binder used in the present invention is composed of tricalcium aluminate (3CaO.5Al ₂ O ₃ ), tricalcium silicate (3CaO.SiO ₂ ), calcium aluminate sulfate (4CaO.3Al ₂ O ₃ .SO ₃ ) and calcium. Fast and high-strength special cement composed of iron, magnesium silicate ((Ca · Fe · Mg) SiO ₃ ) and ordinary portland cement, the chemical composition of which is shown in Table 1.

As a light aggregate and a sound absorbing aggregate having continuous pores, surface-modified expanded pearlite, expanded vermiculite, wood chips and organic fibers (waste fibers discarded at the production plant) and the like are used. Waste fiber is added for the purpose of improving the bending strength and cracking of the plate, and foamed pearlite has a specific gravity of about 0.02 to 0.05, and has a specific porosity of about 50% or more and consists of continuous pores. Can be absorbed and extinguished, while foamed vermiculite, wood chips and waste fibers are also sound absorbing.

Table 1. Chemical Analysis of Cement Compositions

Ingredient Type CaO Al ₂ O ₃ SiO ₂ MgO Fe ₂ O ₃ K ₂ O Na ₂ O TiO ₂ SO ₃ ZnO Special Cement 55.4 13.6 7.1 1.6 2.4 0.46 0.32 0.61 8.2 0.11 Ordinary cement 60.1 8.80 20.0 2.5 1.4 0.86 0.28 - 2.5 -

Foamed vermiculite is composed of expanded plate-shaped crystal grains, which acts as a sound absorbing and insulating effect and a lightweight aggregate, and uses a particle size of 2-3 mm. Wood chips are waste materials produced in mills and the like, and are about 1 to 2 cm in length, about 0.1 mm or less in thickness, about 0.5 cm or less in width, and wood pieces having an average particle diameter of about 5 mm or less.

The surface-modified expanded pearlite has a particle size of about 0.2 to 2 mm and is coated with an alkali silicate on its surface, and an aqueous solution of low alkaline silicate having a molar ratio of silicic acid and alkali (SiO ₂ / M ₂ O) of 3.5 to 5.8 (colloidal) By coating 30% aqueous silica solution on expanded pearlite, it is possible to remarkably improve the water resistance, weather resistance, corrosion resistance, chemical resistance, thermal shock resistance, and abrasion resistance of pearlite, and it is easily cured even at low temperature (below about 300 ℃) and firm adhesive strength To keep it. The spraying amount of the above-mentioned silicate aqueous solution is in the range of 5 to 15% by weight relative to the weight of the expanded pearlite, and the spraying amount of 5% or less may not exhibit sufficient water repellent performance. have. The surface-modified pearlite reacts with the cement in the composition to easily cure even at low temperatures and maintain a firm and constant strength.

What is particular to the present invention is that the surface-treated foamed pearlite has excellent waterproofing and water repellency while maintaining pores (pores) using continuous foaming pores, and greatly improves the water resistance of the mixed composition.

As the foaming agent, dodecyl benzene sodium sulfonate was used.Non-ionic Carboxylated Stylene containing an antioxidant as a polymer modifier to improve performance such as adhesion, water resistance, durability, and freeze thawability (Non-ionic Carboxylated Stylene) Copolymer Emulsion) was used.

In order to manufacture the sound absorbing plate, the composition ratio of the above-mentioned materials is 80 to 30: 20 to 70, and the mixing ratio of the normal cement and the special cement of fast hardening is 65 to 75 weight% of the cement composition, 15 to 30 weight% of pearlite. To the material mixed with 1 to 5% by weight of waste fibers, 0.1 to 0.5% by weight of the foaming agent and 3 to 10% by weight of the polymer modifier are added, and water is added so that the water / cement ratio is 0.45 to 0.65. The mortar was put into a plate-shaped mold, vibrated and molded, and then dried and dried at room temperature (0 to 40 ° C). The products cured for 7 to 28 days were cut into appropriate shapes and sizes and measured for various physical properties. Instead of pearlite, expanded vermiculite or wood chips may be substituted or mixed in the above composition. As antifouling agent, about 1 to 5% by weight of ore mixed with natural tourmaline and barite was ground to fine powder of -200 mesh or less based on the total amount of light-weight sound-absorbing concrete composition.

In the above cement composition, the maximum addition amount of fast cement is limited to 70% by weight in the mixing ratio of Portland cement and fast cement. The initial setting time of mortar is too short (about 15 minutes) above this amount. This is because it is difficult to secure the temperature. At 20 wt% or less, the setting time is long and the strength tends to decrease. If the added amount of pearlite is 30% by weight or more, the proportion of pearlite in the volume ratio of the total composition is 90% or more, which makes it difficult to form mortar and thus has a disadvantage in that the strength is also low.

For the measurement of compressive strength (KS L 5105), cut into cubic shapes of 5 cm x 5 cm x 5 cm, and for the sound absorption measurement (KS F 2805), cut a disk-shaped sample of 10 cm in diameter with different thicknesses. Vertical incidence sound absorption characteristics were investigated.

Next, a method of manufacturing a sound absorbing plate will be described through specific examples.

<Example 1.>

0.2% by weight of foaming agent, 5% by weight of polymer modifier, waste fiber to the total amount of cement-based composition in which the cement composition is a mixture of 70% by weight of Portland cement and 30% by weight of fast cement, and 30% by weight of silicate-coated expanded pearlite. 5 weight% is added and mixed, and the ore powder which mixed 1.5 weight% of tourmaline and barite with respect to the total weight of this mixed composition is added. Water was added so that the water / cement ratio was 0.40, mixed in a mixing mixer, and then poured into a plate-shaped mold and vibrated to naturally cure at room temperature.

<Example 2.>

0.2% by weight of foaming agent, 5% by weight of polymer modifier, 5% of waste fiber to the total amount of cement-based composition in which cement composition is 30% by weight of Portland cement and 70% by weight of fast cement, and 30% by weight of expanded vermiculite is added. Mix by adding% and add ore powder of 1.5% by weight of tourmaline and barite with respect to the total weight of the mixed composition. Water was added at a water / cement ratio of 0.35, mixed in a mixer, mixed in a plate-shaped mold, vibrated, and naturally cured at room temperature.

<Example 3.>

0.2% by weight of foaming agent, 5% by weight of polymer modifier, 5% by weight of waste fiber, based on the total amount of cement-based composition, in which the cement composition usually contains 80% by weight of Portland cement and 20% by weight of fast cement, and 30% by weight of wood chips. The mixture is added and mixed, and an ore powder obtained by mixing 1.5% by weight of tourmaline and barite with respect to the total weight of the mixed composition is added. Water was added at a water / cement ratio of 0.35, mixed in a mixer, mixed in a plate-shaped mold, vibrated, and naturally cured at room temperature.

<Comparative Example 1>

Mixing Mixer Mixing Cement Composition is usually 70% by weight of Portland Cement and 30% by weight of silicate coated expanded pearlite by adding 0.2% by weight of foaming agent and 5% by weight of polymer modifier and adding water so that the water / cement ratio is 0.40. After mixing in the plate-shaped mold was vibrated and molded and then naturally cured at room temperature.

Table 2. shows the results of measuring the physical properties of the products produced by the above examples.

Table 2. Properties of Sound Absorbing Plate

importance Compressive strength (㎏ / ㎠) Bending strength (㎏ / ㎠) ※ Sound absorption rate Example 1 0.65 30 5 0.80 Example 2 0.80 40 10 0.50 Example 3 0.60 30 7 0.70 Comparative Example 1 1,00 70 5 0.30

※ Average sound absorption measured by KS F 2805

The present invention has the effect of improving the economics by improving the added value of the product by the method of manufacturing using a relatively inexpensive material, omitting the curing process of high temperature and high pressure compared to the existing lightweight sound-absorbing concrete. On the other hand, this product can overcome various shortcomings of the existing soundproofing panel, thus making it easy to install and extending its life (weather resistance, freezing and thawing).

Claims (5)

The sound-absorbing lightweight concrete composition of the present invention is 15-30% by weight of surface-modified expanded pearlite, 65-75% by weight of the cement-based composition mixed so that the mixing ratio of ordinary cement and special cement of fast hardness is 80-30: 20-70. Sound-absorbing lightweight concrete composition, characterized in that composed of materials mixed with 1 to 5% by weight of fibers. A method for preparing mortar by adding 0.1 to 0.5% by weight of the foaming agent and 3 to 10% by weight of the polymer modifier to the composition of claim 1 to add water so that the water / cement ratio is 0.45 to 0.65. Method for producing a natural dry curing at room temperature (0 ~ 40 ℃) by injecting the mortar of claim 2. Method for producing a sound-absorbing lightweight concrete by adding expanded vermiculite, wood chips, etc. as a substitute or mixed material of surface-modified expanded pearlite in the composition of claim 1. The foamed pearlite of claim 1 is a surface alkali modifier coated with a low alkali aqueous silicate solution having a molar ratio of silicic acid and alkali (SiO ₂ / M ₂ O) of 3.5 to 5.8 in an amount of 5 to 15% by weight relative to the foamed pearlite, and at about 1 at 250 ° C. Method for producing surface-modified expanded pearlite dried over time