KR100472941B1 - A porous concrete composition having permeability, high strength and durability - Google Patents

Abstract

The present invention helps the natural environment or ecosystem by forming a large number of continuous voids between aggregate particles surrounded by the paste constituting the concrete to pass water or stored in the voids and to create a pleasant environment for the user by using a porous concrete pavement surface. The main method is to manufacture permeable porous concrete. In order to solve the problem of strength and durability degradation of porous concrete with permeability, an appropriate amount of high-performance AE water reducing agent is used as a admixture, and an appropriate amount of fine blast furnace slag powder, which is a mineral admixture, is used for cement content. The purpose of the present invention is to provide a porous concrete composition having a compressive strength of 150 to 350 kgf / cm 2, high durability and permeability of 0.01 to 0.5 cm / sec. have. In order to achieve the above object, the present invention provides 90 to 110 kg of water per 1 ㎥ of permeable porous concrete, water to binder ratio (W / (C + BF)) of 25 to 33% by weight, high performance AE water reducing agent 0.5 to the binder To 2.5% by weight, 2 to 5% by weight of the coloring material to the binder, the aggregate consists of 1500 to 1750kg of the maximum size 13mm or 10mm aggregate, but the cement and blast furnace slag fine powder as a binder, characterized in high strength and durability Genie relates to a permeable porous concrete composition.

Description

A porous concrete composition having permeability, high strength and durability

The present invention relates to the production of permeable porous cement concrete composition for paving having a wide area such as sidewalks, roads, parking lots.

The pavement of the road is mainly used for asphalt pavement and concrete pavement. However, impervious pavements have a disadvantage in that when there is no drainage or incomplete drainage, the water is not drained well and the road surface is impregnated and the slip resistance is reduced. In addition, water does not penetrate into the ground and flows to the surface of the package, which flows into sewer pipes and streams, causing groundwater depletion and flooding of rivers as the inflow of water into the rivers accelerates during heavy rains. There are many problems in terms of natural environment, such as poor growth.

As a way to solve such problems, interest in permeable pavement has been developed, and since 1980, developed permeable asphalt has been used for pavement such as living-related roads, plazas and parking lots, mainly on sidewalks. However, permeable asphalt pavement has been developed due to the disadvantage of loss of permeability due to deformation of the road surface when the temperature of the road surface rises in the summer, and now permeable concrete has been developed. It is becoming.

Permeable concrete is made of porous concrete with continuous pores in order to allow water to permeate, using coarse aggregates of a certain size. The strength of concrete decreases with increasing porosity, while the permeability increases with increasing porosity. Accordingly, studies have been actively conducted to manufacture permeable porous concrete having appropriate levels of permeability and strength. For example, Korean Patent Publication No. 90-4390 provides water permeable concrete mixed with water 116kg / ㎥, cement 292kg / ㎥, fine aggregate 87kg / ㎥, coarse aggregate 1690kg / ㎥, pigment 7kg / ㎥, admixture 0.58kg / ㎥. In No. 91-6894, water-permeable concrete composed of 300 to 400 kg of Portland cement per m3 of concrete, 0.005 to 0.1 parts by weight of binder, and 0.35 to 0.45 parts of water and aggregates based on 1 part by weight of cement is used. In Korean Patent Laid-Open No. 97-21018, the amount of cement is added to 120 to 130 kg / m3 of water, 270 to 340 kg / m3 of cement, 1530 to 1920 kg / m3 of aggregates having a size of 6 to 10 mm, and 14 to 20 kg / m3 of pigment. Permeable concrete mixed to within 0.3% of.

On the other hand, U.S. Patent No. 3,870,422 (registered Mar. 11, 1975) has an average diameter of about 1/4 inch and the volume ratio of the mixture of cement, sand and coarse aggregate is 1: 0: 3 or 1: 1 /. A technique for producing permeable pavement concrete having high permeability (1 inch per second) with a ratio of 4: 3 and a volume ratio of a mixture of adhesive and water is 1: 3.

However, these technologies show a limitation in increasing strength and durability by forming a high mixing ratio of water and cement. In general, concrete can be said to be a concrete having a higher strength and durability the more dense configuration. However, since permeable porous concrete is manufactured to have high continuous porosity to secure permeability, strength and durability are greatly reduced compared to general concrete. Therefore, in order to remedy these disadvantages, it is most practical to lower the unit quantity of concrete as much as possible. This will improve strength or durability.

In addition, while permeable porous concrete has a natural environmental friendliness due to permeability, the problem of deterioration in strength due to porosity and durability deterioration, that is, the speed of neutralization by harmful substances in the air due to continuous pores is rapidly progressing. The durability of the concrete construction is shortened by exposing the void surface inside the concrete to various extreme external environments such as a decrease in the resistance to freezing expansion due to moisture inflow into the void.

The present invention is to solve this problem by using an appropriate amount of high performance AE reducing agent as admixture when mixing concrete, and by using an appropriate amount to replace the ground granulated Blast-Furnace Slag (BF) with respect to the cement weight as a mineral admixture, High-performance AE water-reducing agent and blast furnace slag fine powder are mixed with water, cement, and aggregate, and the optimum mixing ratio is derived. The strength and durability of permeable porous concrete are significantly improved than before, with 28-day compressive strength of 150 to 350kgf / ㎠ and high durability. It is an object to provide a permeable porous concrete having a permeability coefficient of 0.01 to 0.5 cm / sec.

In order to achieve this purpose, the maximum dimension of aggregate per 1m3 of concrete is 13mm or 10mm, and the aggregate weight is 1500-1750kg, which is 5-30% of the weight ratio of 5mm sieve, and the amount of water is 90-110kg, and the binder is cement and cement. 20 to 50% by weight of blast furnace slag fine powder having a powder degree of 2750 to 8000 cm 2 / g is used, and the ratio of water to binder (W / (C + BF)) is 25 to 33% by weight, high performance. The feature of the present invention is that the AE reducing agent is 0.5 to 2.5% by weight with respect to the binder, and the coloring material is 2 to 5% by weight with respect to the binder.

In the present invention, the aggregate of the maximum dimension 13mm or aggregate size of 10mm maximum 1500mm to 1750kg is used in the present invention and the amount of water is 90 to 110kg, water-binder ratio (W / (C + BF)) of 25 to 33% by weight, 0.5 to 2.5% by weight of the high-performance AE water reducing agent and 2 to 5% by weight of the binder in the colorant, but generally the permeability and strength characteristics of the permeable porous concrete are incompatible with each other. To increase the permeability, while the permeability is lowered, the strength tends to be lowered. Therefore, in order to provide an optimal permeable concrete, an optimal mixing ratio should be selected for the concrete mixing components.

In the present invention, aggregate is 5 to 30% of the aggregate weight percentage of the 5mm sieve as a general crushed aggregate, but when the percent by weight of the 5mm sieve is less than 5%, the water permeability is good but there is a problem of reduced strength and exceeds 30%. In this case, the strength increases, but the water permeability decreases. Therefore, the aggregate used is aggregate of 13 ~ 2.5mm of aggregate according to Korean Industrial Standard (KSF2527), all the 19mm sieve passes through 90mm of the total weight of 13mm sieve, 40 ~ 75% of the passing weight percent of 10mm sieve, 5mm The through weight percentage of the sieve is 5 to 25%, the through weight percentage of the 2.5mm sieve is 0 to 10%, and the passing weight percentage of the 1.2 mm sieve is 5% or less. The through weight percentage of the sieve is 85 to 100%, the through weight percentage of the 5 mm sieve is 10 to 30%, the passing weight percentage of the 2.5 mm sieve is 0 to 10%, and the passing weight percentage of the 1.2 mm sieve is 5% or less.

Although only Portland cement has been generally used as a binder in water-permeable concrete, in the present invention, the composition ratio of the binder is 80 to 50 wt% of cement and 20 to 50 wt% of blast furnace slag powder having a powder degree of 2750 to 8000 cm2 / g. In comparison with the use of blast furnace slag fine powder, the compressive strength of concrete is increased by 5 to 15%.

By using blast furnace slag powder as part of the binder, it has advantages such as reduction of unit quantity, improvement of long-term strength, utilization of waste resources and cost reduction, and the color tone of concrete that is slightly white, which is advantageous for coloring. Since the opening of the cotton is delayed (especially at low temperatures, the curing period is long) and the initial strength is lowered. Therefore, the blast furnace slag fine powder for cement is considered in consideration of curing period, unit quantity reduction effect and strength enhancement effect under the climatic condition of 10 ℃ or higher. The range of substitution rate of is set to 20 to 50% by weight. In the range of 25 to 33% by weight of the water-binding material (W / (C + BF)), which is the constituent of the present invention, when the substitution rate of the blast furnace slag is less than 20% by weight, the effect of reducing the unit quantity is small and the substitution rate is 50%. In the case of%, the amount of unit is reduced by 5 to 10% as compared with the case where no fine blast furnace slag is mixed, but when the substitution rate exceeds 50% by weight, the effect of increasing strength is reduced.

In addition, considering that permeable porous concrete is much lower than general concrete, when permeable porous concrete is replaced by a certain amount of cement with blast furnace slag, it is very advantageous to reduce unit quantity and develop long-term strength. When used in combination with a water reducing agent, the strength or durability index can be enhanced.

In particular, in the summer when the temperature is high, the condensation of concrete is accelerated, and the workability is inferior. The use of the delay time of condensation according to the amount of blast furnace slag powder can be used to extend the time required for transporting and laying concrete. The quality of concrete can be improved.

On the other hand, permeable porous concrete is manufactured to have high porosity in order to secure permeability, so strength and durability are lowered compared to general concrete. As a countermeasure, chemical admixtures having superior water-resistance performance than conventional water reducing agents are used as a countermeasure. Lowering the water-binder ratio (W / (C + BF)) is the most realistic means.

In the present invention, a high performance AE water reducing agent, which is a chemical admixture, is used for concrete mixing.

The history of chemical admixtures for concrete began with the development of water sensitizers and AEs around 1940, and the development of high performance water sensitizers or glidants in Germany in 1970. Or it is widely used for the manufacture of concrete with good workability. However, high-performance water-reducing agent or fluidizing agent greatly reduces the unit quantity, and even if a relatively large amount is used, there is an advantage that there is no adverse effect such as condensation delay or excessive entrainment of air bubbles, whereas rapid slump loss occurs depending on the elapsed time after mixing. There are drawbacks to the use constraints of finishing the concrete stroke within the fast time after mixing.

In order to solve this problem, in the case of the fluidizing agent, there are many examples in which the admixture is added to the agitator drum at the construction site. The fluidization work in the construction site includes the management of the input of the fluidizing agent, the quality confirmation of both the base concrete and the fluidizing concrete. It causes a lot of problems such as management, ready-mixed car exhaust, noise, etc

In particular, the permeable porous concrete is made of dough and transported to the dump truck, so the dough kneading can be changed greatly according to the transport time, and in this case, the compaction work may be insufficient, resulting in quality deterioration.

On the other hand, the use of a relatively high performance AE water reducing agent, which has been developed recently, has a great advantage that it is possible to simultaneously mix in different batching plants together with other materials and then transport them to the site because the slump loss is very small.

As a high performance AE reducing agent, various admixtures such as polycarboxylic acid, melamine, and naphthalin are commercially available, and when less than 0.5% by weight of cement is added, air entraining and water-reducing effects are not exhibited and concrete strength is expected to be increased. It is difficult to do so, when the addition of more than 2.5% by weight, the loss of slump over the elapsed time and entraining the air amount excessively to reduce the strength of the concrete, in the present invention, the amount of high-performance AE water reducing agent 0.5 to 2.5% by weight relative to the binder When the amount of the blast furnace slag fine powder was increased, the amount of the high performance AE reducing agent was also considered.

On the other hand, another effect of lowering the water-binding ratio (W / (C + B.F)) by the use of a high performance AE reducing agent is improved durability such as freeze resistance, resistance to neutralization and abrasion resistance.

[Table 1] shows the 28-day compressive strength and coefficient of permeability according to the permeable concrete mix when 0.3% by weight of general AE water reducing agent is used with respect to cement which is the optimum standard amount and 1.0% by weight of high performance AE water reducing agent is used. It is an Example tested.

[Table 1] Properties of Permeable Concrete Using AE Reducing Agent and High Performance AE Reducing Agent

Experiment result

No. Water-Cement Ratio W / C (%) Unit weight (kg / ㎥) Experiment result Water (W) Cement (C) aggregate AE Supervisor High performance AE water reducer Compressive strength (kgf / ㎠) Permeability coefficient (cm / sec) One 38 115 300 1562 0.9 - 165 0.31 2 34 120 350 1546 1.05 - 190 0.21 3 31 125 400 1529 1.2 - 229 0.14 4 32 95 300 1562 - 3.0 189 0.42 5 29 100 350 1546 - 3.5 227 0.29 6 26 105 400 1529 - 4.0 266 0.15

Comparing the experimental results of [Table 1], when the high performance AE water reducing agent is used, the coefficient of permeability is slightly improved compared to the concrete using the conventional AE water reducing agent, the unit water quantity is reduced by about 20 kg, and the compressive strength is 15 to 20% increase in high performance AE reducing agent is very effective in improving the strength of permeable porous concrete.

The reason why the ratio of water-bonding material is in the range of 25 to 33% by weight is less than 25% by weight of cement paste and aggregates, and the compaction work is poor. Because of its high fluidity, it flows down between the aggregate particles, blocking pores at the bottom, and the tendency of material separation is high, resulting in a defect in permeable concrete strength. The amount of cement paste should be in such a way that it will surround the aggregate to form a film that shines like metal and the cement paste should not be allowed to flow down.

On the other hand, permeable porous concrete is known to have low freeze-thawing resistance compared to general concrete by freeze-expansion because water is easily introduced into the pores because a large amount of continuous pores exist. However, according to the results of the outdoor exposure test of the cold district, the permeability of the concrete is good if the ratio of water-binder is low and the freeze-thawing resistance can be improved by using high performance AE reducing agent and blast furnace slag powder in concrete of such structure. have.

Pavement-permeable porous concrete can produce various colors using pigments. The type and amount of pigments greatly affect the physical properties of the mortar, and in the examples of [Table 2], green and blue colors can reduce the strength of the permeable porous concrete. Therefore, in the present invention, the amount of the inorganic pigment is used in the range of 2 to 5% by weight based on the binder. In addition, the surface treatment agent containing a pigment such as acrylic or urethane-based resin and iron oxide pigment in order to make the color more clear and the color lasts for a long time was applied to a thickness of less than 1mm using a brush or a spray.

As a pigment used as a coloring material, pigments such as synthetic iron oxide, chromium oxide, and phthaloxyan series are generally used.

[Table 2] Compressive strength (kgf / ㎠) test results of the mortar age of 28 days using inorganic pigments

Pigment Usage (C ×%) Compressive strength (kgf / ㎠) Red (iron oxide) Yellow (iron oxide) Phthalocyanine green Phthalocyanine blue Black (iron oxide) 0 391 391 391 391 391 2 385 394 202 200 389 4 392 393 132 174 387 6 422 430 130 146 374 8 440 418 126 134 413 10 425 433 126 158 398

Note) Name of Pigment

Unlike ordinary concrete, permeable porous concrete is affected by compaction as well as water-binder ratio (W / (C + B.F)). As the porosity increases, the strength decreases in proportion to the increase in the permeability. Therefore, it is necessary to ensure that the requirements for strength and permeability are met. In the present invention, the permeable porous concrete is compacted to have a porosity of 5 to 25% and a permeability coefficient of 0.01 to 0.5 cm / sec.

Problems in strength and durability deterioration in conventional permeable porous concrete are based on high performance AE water reducing agent and blast furnace slag powder, which are the characteristic components of the present invention, and after determining the optimum mixing ratio for each mixing element, the porosity is adjusted by voltage compaction. By doing so, it is possible to provide concrete having high strength, durability, and permeability required.

The present invention uses a high-performance AE water reducing agent in an appropriate amount to solve the problems of strength and durability deterioration in conventional permeable porous concrete, and by adjusting the mixing elements of water, binder, aggregate, high strength and durability as well as required Permeable porous concrete composition having a permeability coefficient can be prepared, and by using a certain amount of blast furnace slag fine powder substituted for cement, it is possible to improve long-term strength and constructability as well as to recycle waste resources and reduce costs.

Claims (1)

In permeable porous concrete composition composed of aggregate, water, binder, high performance AE water reducing agent and coloring material, 1500-1750 kg of aggregate having 5-30% by weight of 5mm sieve with a maximum dimension of 13 mm or less per 1m3 of permeable concrete 90 to 110 kg of water, and the composition ratio of the binder to 80 to 50% by weight of cement and 20 to 50% by weight of blast furnace slag fine powder, the ratio of water to the binder (W / (C + BF)) The water-permeable porous concrete composition having a high strength and durability of 25 to 33% by weight, 0.5 to 2.5% by weight of the high-performance AE reducing agent, and 2 to 5% by weight of the coloring material.