KR100948884B1 - Recycling asphalt concrete for subbase layer of way using waste asphalt concrete and cinder - Google Patents

Abstract

PURPOSE: A room temperature recycling asphalt concrete for a sub-base layer using waste asphalt concrete and coal dust is provided to prevent carbon dioxide and toxic gas which is generated in heating concrete by manufacturing the concrete at room temperature without heating process. CONSTITUTION: A room temperature rejuvenated asphalt concrete for a sub-base layer comprises: coal dust 5 - 100 parts by weight; waste limestone or granular activated charcoal 1 - 12 parts by weight; blister steel low heat mixed cement 5 - 20 parts by weight; reject ash 0.1 - 10 parts by weight; anhydrous gypsum or blending material 0.1 - 5 parts by weight; an emulsifier 0.1 - 1 parts by weight; an elastomer 0.1 - 10 parts by weight; and calcium silicate aqueous solution 0.1 - 10 parts by weight.

Description

Recycling asphalt concrete for subbase layer of way using waste asphalt concrete and cinder}

The present invention is a room temperature recycled asphalt for road foundations that recycled coal ash, which is increasing its emissions from thermal power plants due to the increase in the demand for waste asphalt concrete, waste concrete, waste limestone, and electricity. It's about concrete.

The recycling of waste asphalt concrete, waste limestone, and waste concrete can be used as a method of overcoming the difficulty of securing resources due to lack of aggregates, as well as securing landfill sites for the waste disposal, burden on costs, and the need for environmental conservation. .

For this reason, researches to manufacture recycled asphalt concrete and improve its performance by recycling waste asphalt concrete have been made. In general, waste asphalt concrete has been used to produce recycled asphalt concrete by heating after mixing the additive and the modifier together with the new asphalt. For example, Korean Unexamined Patent Publication No. 10-2004-0091283 "Waste ascon (hereinafter referred to as" waste asphalt concrete "generated by cutting on the surface and base of asphalt pavement) waste ascon" It is known to make recycled ascons by crushing waste ascons having a predetermined particle size distribution and heating them by mixing atomized sand, sand, stone powder and asphalt oil. Korean Registered Patent Publication No. 10-0416301 "Reclaimed Asphalt Concrete Containing Recycled Additives for Recycling Waste Asphalt Concrete" includes recycled asphalt comprising reclaimed additives of paraffin base oil, aromatic base oil and naphthenic base oil in the waste asphalt concrete. Concrete is known. In Korean Patent Publication No. 10-599492 “Semi-rigid packaging composition and packaging method using waste ascon”, crushed waste ascon which provides flexibility, cement and sand which provide rigidity, index agent to prevent rapid evaporation of water, cement Semi-rigidity, characterized in that it is composed of a volume expansion agent to compensate for shrinkage of the film, and a solid admixture composed of an ionic curing accelerator to shorten the curing time of the package and a fluid admixture to impart fluidity, adhesion and elasticity. It is known to relate to packaging compositions.

Recycled asphalt concrete recycled waste asphalt concrete known in the prior art is vulnerable at low temperatures due to high temperature heating process, shortening the life, securing quality and environmental pollution, as well as problems such as cracking, durability, fluidity and water tightness due to premature shrinkage Indicates.

In order to solve the above problems, the present invention is to recycle waste asphalt concrete, waste concrete, waste limestone, which is a construction waste that is rapidly increasing with coal ash recovered from a thermal power plant as an aggregate resource, specifically the present invention is a high temperature heating It can be manufactured at room temperature without going through the process to prevent carbon dioxide or harmful gases that may occur during heating, and for road substrates to secure early strength, increase durability, prolong life, suppress cracks and improve watertightness such as turtles on inner and surface layers. Presents room temperature reclaimed asphalt concrete.

The present invention for achieving the object as described above is a room temperature for road substrates produced by mixing the fillers and additives with waste asphalt concrete, waste concrete and waste limestone obtained from various industrial wastes and by-products and coal ash that can be recovered from thermal power plants The present invention relates to recycled asphalt concrete, and more particularly, to produce waste asphalt concrete aggregate having the predetermined particle size distribution, and mixing coal ash with a filler, an additive, and mixed water so as to enhance the binding force of the asphalt concrete.

The filler may be used as a mixture of waste limestone or granular activated carbon, reject ash and anhydrous gypsum or high-strength concrete, and may be used by mixing calcium silicate or sodium silicate.

The additive uses a crude low heat generation cement, emulsifier, and polyvinyl alcohol fiber, and may further use an elastomer.

The present invention uses waste ascon and coal ash as a filling material, and by using a specific filling material and additives in a specific content, can be installed at room temperature, while suppressing the emission of carbon dioxide or harmful gases, excellent early strength expression and durability, KS F The present invention has been completed by discovering that the reference value of the room temperature asphalt mixture specified in 2369 can be met.

Specifically, the present invention is a waste coal asphalt aggregate a) coal ash; b) activated carbon in the form of waste limestone or granules; c) crude low heat mixing cement; d) reject ash; e) admixtures for anhydrous gypsum or high strength concrete; f) emulsifiers; g) polyvinyl alcohol fibers; h) It relates to room temperature regenerated asphalt concrete for road substrates containing mixed water.

More specifically, the present invention is based on 100 parts by weight of waste asphalt concrete aggregate; a) 5 to 100 parts by weight of coal ash; b) 1 to 12 parts by weight of activated lime or granular activated carbon; c) 5 to 20 parts by weight of crude low heat generation cement; d) 0.1 to 10 parts by weight of reject ash; e) 0.1 to 5 parts by weight of an admixture for anhydrous gypsum or high strength concrete; f) 0.1 to 10 parts by weight of an emulsifier; g) 0.01 to 0.5 parts by weight of polyvinyl alcohol fiber; h) mixed water 0.5 to 5 parts by weight; and relates to room temperature reclaimed asphalt concrete for road substrates including.

The room temperature regenerated asphalt concrete for road substrates further includes adding waste concrete.

The room temperature regenerated asphalt concrete for road substrates further includes adding an elastomer, and the elastomer may be selected from styrene-based, olefin-based, urethane-based, polyester-based, and polyamide-based polymer groups.

The room temperature regenerated asphalt concrete for road substrates further includes adding calcium silicate or sodium silicate aqueous solution.

Hereinafter, the present invention will be described in more detail.

In the present invention, the waste asphalt concrete aggregate is used for the base layer, and since the base layer is a portion directly receiving the load of the surface layer, it is important that the particle size of the aggregate is evenly distributed. Therefore, the waste asphalt concrete aggregate is used by adjusting the particle size of the waste asphalt concrete obtained from industrial waste and by-products. The particle size of the waste asphalt concrete aggregate used in the present invention has a maximum particle diameter of 40 mm or less, a 20 mm mass ratio of 55 to 90 wt%, a 10 mm mass mass of 40 to 70 wt%, and a 0.6 mm mass mass of 7 to 7 mass. 26 wt%. If the waste asphalt concrete aggregate is out of the above range, it may contain water, and thus the strength may be weakened.

In the present invention, a) coal ash may be weak because there are many pores in itself, but the filler and additives are mixed to increase the binding strength of the asphalt concrete.

The coal ash is used 5 to 100 parts by weight based on 100 parts by weight of waste asphalt concrete aggregate. When the content of the coal ash is less than 5 parts by weight, there is a limit that the filler and the additive is mixed and filled, so that the strength of the asphalt concrete may not be enhanced and the strength may drop. Many pores cause the strength to drop.

In the present invention, b) waste limestone is a fine powder of waste lime with a particle size of 2.5mm or less to increase the curing rate during the hydration reaction of cement and water and to increase the bonding strength and marshall stability by filling the space between the aggregate and the emulsion and cement paste.

The waste limestone is used 1 to 12 parts by weight based on 100 parts by weight of waste asphalt concrete aggregate. When the content of the waste limestone is less than 1 part by weight, the curing rate may be slow and the bonding strength may be weakened. In addition, granular activated carbon may be used in place of the waste limestone, and when used in the range of 1 to 12 parts by weight, curing may proceed rapidly while increasing bonding strength and Marshall stability, which is advantageous for early curing.

In the present invention, c) crude low heat generation mixed cement can reinforce the decrease in initial strength of mixed cement and control cracks and plastic cracks caused by dry shrinkage due to initial heat of hydration after construction. The crude low heat generation cement is used 5 to 20 parts by weight based on 100 parts by weight of waste asphalt concrete aggregate. When the content of the crude steel low heat generation cement is less than 5 parts by weight, the initial strength cannot be reinforced, and dry shrinkage due to hydration heat cannot be prevented.

In the present invention, d) the reject ash has a thermal loss of 5% or more and a powder degree of 2500 cm ² / g or more in the refining process of fly ash, a by-product generated from a thermal power plant. It fills the space between the emulsion and the long-term strength due to the pozzolanic reaction. The reject ash is preferably used 0.1 to 10 parts by weight based on 100 parts by weight of waste asphalt concrete aggregate. If the content of the reject ash is less than 0.1 parts by weight can not be expected long-term strength improvement, if more than 10 parts by weight can not be expected to increase the strength.

In the present invention, e) admixture for anhydrous gypsum or high strength concrete increases initial strength and shows durability in the long term. The admixture for anhydrous gypsum or high strength concrete is preferably used 0.1 to 5 parts by weight based on 100 parts by weight of waste asphalt concrete aggregate. When the content of the admixture for anhydrous gypsum or high-strength concrete is less than 0.1 parts by weight, the durability is lowered, and when it exceeds 5 parts by weight, cracking occurs due to the improvement of the hydration reaction rate of the cement paste.

The high-strength concrete admixture is composed of 5 to 30 parts by weight of anhydrous gypsum, 10 to 40 parts by weight of blast furnace slag, 10 to 30 parts by weight of sulfur wood yarn, and ground to a particle size of 6,000 to 10,000 cm ² / g.

In the present invention, f) the emulsifier is used to prevent the phase separation of the asphalt concrete and maintain the dispersed state using 0.1 to 10 parts by weight based on 100 parts by weight of waste asphalt concrete aggregate. When the content of the emulsifier is less than 0.1 parts by weight, it is difficult to disperse, and when the content of the emulsifier is more than 10 parts by weight, the fluidity increases to decrease the strength.

The emulsifiers include polyoxyethylene lauryl ether, polyoxyethylene sorbitan trioleate, polyoxyethylene stearate, polyethylene oxide, polyoxyethylene sorbitan fatty acid esters, sodium oleate, potassium oleate, cetylethyl morpholiniumate The selected one of the sulfates is used in combination.

In the present invention, g) polyvinyl alcohol fiber is a hydrophilic, high toughness fibrous new material, which has the effect of increasing the toughness of asphalt concrete at room temperature, dispersing effect of cracks under load, freezing thawing and impact resistance, and increasing porosity in the aggregate itself. Strength and durability are improved by entangled with emulsions and paste pastes between many coal aggregates.

The polyvinyl alcohol fiber is preferably used 0.01 to 0.5 parts by weight based on 100 parts by weight of waste asphalt concrete aggregate. If the content of the polyvinyl alcohol fiber is less than 0.01 to less than the effect of strength and durability, it may be vulnerable to impact when more than 0.5 parts by weight.

In the present invention, h) the mixed water is used 0.5 to 5 parts by weight. If the content of the mixed water is less than 0.5, the dispersion is not made well, if the content of more than 5 parts by weight increases the fluidity is lowered.

In the present invention, the room temperature regenerated asphalt concrete prepared by mixing a) to h) in the waste asphalt concrete aggregate can secure an early increase in strength and durability due to the above combination, and can suppress internal cracking. By doing so, it is possible to overcome the cracks due to early shrinkage and weakening of long-term durability, lack of fluidity, water tightness due to early shrinkage.

In the present invention, the waste concrete aggregate may be added by adding 1 to 50 parts by weight. The waste concrete aggregate is to adjust the particle size of the waste concrete to a maximum particle diameter of 5 ~ 40mm, 20mm mass fraction is 35 to 70% by weight, 10mm mass fraction is 10 to 30% by weight, 5mm mass fraction is Up to 5% by weight, preferably 0.1 to 5% by weight. The waste concrete can increase the strength by promoting the bonding force with the waste limestone as a filler. If the content of the waste concrete aggregate is less than 1 part by weight can not see the effect of improving the binding force, if the amount exceeds 50 parts by weight rather falls.

In addition, in the present invention, 0.1 to 10 parts by weight of the elastomer may be further mixed. The elastomer includes a block copolymer composed of a polystyrene block and an elastomer block of a polyolefin structure, exhibits rubbery properties over a wide temperature range, and has excellent fluidity, flexibility, and chemical resistance to acids, alkalis, alcohols, and the like.

When the content of the elastomer is less than 0.1, the flexibility and elasticity and the chemical resistance can not be seen, and when more than 10 parts by weight, the strength and durability are inferior.

The elastomer may be selected from styrene-based, olefin-based, urethane-based, polyester-based, and polyamide-based polymer groups, and preferably, styrene-butadiene-styrene block copolymers having high elasticity and excellent deformation recovery properties are used.

In the present invention, 0.1 to 10 parts by weight of calcium silicate or sodium silicate aqueous solution may be further mixed. The calcium silicate or sodium silicate aqueous solution is an aqueous solution of 10-50% of calcium silicate and sodium silicate solution with respect to 100% of water, and when mixed with room temperature asphalt concrete, not only increases the bonding strength of each material but also operates the vehicle after construction in a short time. When it is necessary to quickly increase the curing period by adding calcium silicate or sodium silicate aqueous solution. If the content of the calcium silicate or sodium silicate aqueous solution is less than 0.1 parts by weight, the effect of the early strength is not seen, if more than 10 parts by weight is less durable.

That said calcium silicate has a SiO ₂ containing 15 to 25% by weight, K ₂ O 4 to 25% by weight, and the molar ratio of SiO ₂ and K ₂ O 1.5 to 5.1 and a density of 1.1 to 1.6g / cm ^2, Solid silicate content of 15 to 45% by weight, sodium silicate containing 20 to 40% by weight of SiO ₂ , 5 to 20% by weight of Na ₂ O, density 1.3-2.8g / cm ² , water insoluble 0.25% or less It is preferable to use those whose pH concentration is 11-13.

Room temperature regenerated asphalt concrete using waste asphalt concrete and coal ash proposed by the present invention is generated more than about 6 million tons per year due to the increase of waste asphalt concrete and waste concrete and electric power demand, which are caused by the expansion and repair of national infrastructure industry. By recycling coal ash as natural aggregate substitute for asphalt concrete, it can be expected to prevent environmental pollution, prevent exhaustion of natural resources, and reduce treatment costs.

In addition, the crude low heat mixing cement and rejects are used as a filler to prevent premature strength and durability deterioration and lowering of adhesive strength of waste asphalt concrete, coal ash and waste concrete. Ash, anhydrous gypsum or high-strength concrete admixture, and waste limestone or granular activated carbon are used, and as a new reinforcing fiber material, hydrophilic and high toughness polyvinyl alcohol fibers are mixed to reduce the problems of strength and durability of conventional regenerated asphalt concrete. At the same time, the secondary maintenance costs for repair and reinforcement due to the defect of the packaging structure can be reduced.

Hereinafter, the present invention will be described by way of example for specific description of the present invention, but the present invention is not limited to the following examples.

The following examples and comparative examples show whether the room temperature regenerated asphalt concrete for road substrates using waste asphalt concrete and coal ash according to the present invention satisfies the standard value of the room temperature asphalt mixture specified in KS F 2369.

Measurement of stability, flow value and porosity of room temperature regenerated asphalt concrete for road substrates are as follows: KS F 2337 "Test Method for Resistance to Plastic Flow of Asphalt Mixture Using Marshall Tester" and KS F 2364 "Test Method for Porosity of Compacted Bituminous Mixture" It carried out according to.

The formulation of the comparative example and the embodiment of the room temperature regenerated asphalt concrete for road substrates according to the present invention is shown in Table 1 below.

The comparative example mixed waste asphalt concrete, ordinary portland cement, emulsifier, SBR polymer and mixed water.

In the above examples and comparative examples, the waste asphalt concrete has 32% by weight of aggregates of 40 to 20 mm, 16% by weight of aggregates of 20 to 10 mm, 46% by weight of aggregates of 10 to 0.6 mm, and 6 weight of aggregates of 0.6 mm or less. %, A density of 2.2 to 2.7 g / cm ² , a unit volume mass of 1,200 to 1,700 kg / m ³ , and a water absorption of 0.8 to 7% were used. Coal ash density 2.0 to 2.8g / cm ² , unit volume mass 1,200 to 1,600kg / m ³ , the absorption of 0.8 to 6% was used, waste limestone was used as a fine limestone powder of less than 2.5mm in particle size, the common portland cement Density 3.15g / cm ² was used, the crude low heat generation cement was 2.91g / cm ² density, powder 4,231cm ² / g or more, loss of ignition 1.5%, reject ash density 2.2g / cm ² , powder degree of 3,000cm ² / g, loss of ignition 6% was used, the emulsifier used evaporation residue 69%, viscosity 25mPs, storage stability of less than 1%, elongation 50 or more, high strength concrete admixtures 70,000cm ² / g was used, polyvinyl alcohol fiber density 1.3g / cm ² , length 12cm, tensile strength 1,700MPa or more, elastic modulus of 45GPa was used, SBR (styrene butadiene rubber) polymer compound density 1.12 g / cm ² , viscosity 78mPs, solid content 50.0%, pH 9.3 SBS (styrene butadiene styrene) polymer compound has a density of 1.1g / cm ² , a viscosity of 80mPs, a solid content of 48.7%, pH 9.5, the elastomer has a density of 0.9 to 1.0g / cm ² , Styrene content 25 to 60% by weight was used, and calcium silicate had a molar ratio (SiO ₂ / K ₂ O) of 1.5 to 5.1, a density of 1.3 g / cm ² , and sodium silicate having a density of 1.5 g / cm ² , pH 11-13 was used.

[Table 1] Comparative Examples and Examples of Room Temperature Regenerative Asphalt Concrete for Road Substrate

The following Table 2 compares the Marshall stability, flow value, and porosity as a quality test result of room temperature regenerated asphalt concrete for road substrates according to Comparative Examples and Examples.

[Table 2] Quality test results of room temperature reclaimed asphalt concrete for road substrates

As shown in Table 2, the comparative example was less than the Marshall stability value at the standard value of the room temperature asphalt mixture, the room temperature asphalt concrete for road substrates according to the present invention showed more than the quality test results in all of the Examples 1 to 7 above. It was.

Example 1 is a combination of coal ash, waste limestone, low heat exothermic cement, reject ash, anhydrous gypsum, emulsifier, polyvinyl alcohol fiber and mixed water in the combination according to the present invention, Marshall stability is 34.8% compared to the comparative example Increased, the porosity was reduced by 15.8%, it was confirmed that the strength and water tightness is improved by the combination.

In Example 2, the waste concrete was further mixed compared to Example 1, and the Marshall stability was 5.3% lower than that of Example 1, but the Marshall stability was increased by 34.9% compared to the Comparative Example, thereby improving the strength and water tightness.

Example 3 mixed the elastomer in addition to the composition of Example 1. It was confirmed that the elastomer has excellent affinity with cement paste and the stability of Marshall was increased by increasing the bonding strength of the asphalt mixture at room temperature as a polymer compound.

Example 4 mixed calcium silicate in addition to the composition of Example 3. As a result, Marshall stability increased 46.0% compared with the comparative example. This promotes the hardening reaction of the asphalt mixture at room temperature by mixing calcium silicate, which increases the rigidity and improves the bonding strength between aggregate, emulsion, and cement paste.

Example 5 mixed the high-strength concrete admixture with the composition of Example 1 in place of anhydrous gypsum. As a result, it was confirmed that Marshall stability and flow value similar to Example 1 were secured, and that Marshall stability was increased as compared with the comparative example as a admixture to enhance the hydration reaction of cement.

Example 6 mixed the thermoplastic SBS polymer compound in the composition of Example 3 in place of the elastomer. As a result, the value similar to the case of Example 3 was shown.

Example 7 was performed by replacing calcium silicate with sodium silicate in the composition of Example 4. As a result, there was no difference in the porosity and the flow value, but it was confirmed that the Marshall stability value decreased.

As shown in Table 2, the flow value is reduced by 8.6 to 22.9% as a result of the Examples 1 to 7 compared to the comparative example, which confirms that the stiffness of the room temperature asphalt mixture is increased due to the combination of the present invention. In addition, the porosity was confirmed that the value is reduced by 14.7 to 22.1% as the pore is filled due to the mixing of the present invention.

In addition, the combination according to the present invention can be confirmed that the room temperature regenerative asphalt concrete for road substrates has increased watertightness, so that the density value is increased by about 1.8 to 3.2% in Examples 1 to 7, as shown in Table 2 above. there was.

Particularly, in Examples 4 and 7, the incorporation of calcium silicate and sodium silicate increased the early durability, and the Marshall stability value after three hours of test specimen production showed more than the reference value, which urgently required such a shortening for repair. It can be confirmed that the section can be used during construction, and has an excellent characteristic that can significantly reduce the fall of the aggregate compared to the comparative example.

Claims (5)

Per 100 parts by weight of waste asphalt concrete aggregate; a) 5 to 100 parts by weight of coal ash; b) 1 to 12 parts by weight of activated lime or granular activated carbon; c) 5 to 20 parts by weight of crude low heat generation cement; d) 0.1 to 10 parts by weight of a reject ash having a thermal loss of 5% or more and a powder degree of 2500 cm ² / g or more during fly ash purification; e) 0.1 to 5 parts by weight of an admixture for anhydrous gypsum or high strength concrete; f) selected from polyoxyethylene lauryl ether, polyoxyethylene sorbitan trioleate, polyoxyethylene stearate, polyoxyethylene sorbitan fatty acid ester, sodium oleate, potassium oleate, cetylethyl morpholinium sulfate 0.1 to 1 part by weight of an emulsifier; g) 0.1 to 10 parts by weight of an elastomer selected from the group consisting of styrene, olefin, urethane, polyester, and polyamide polymers; And h) 0.1 to 10 parts by weight of an aqueous calcium silicate solution. The method of claim 1, Based on 100 parts by weight of the waste asphalt concrete aggregate, room temperature regenerated asphalt concrete for road substrate further adding 1 to 50 parts by weight of waste concrete aggregate. delete delete delete