JP2013100662A - Porous concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such porous concrete as achieving a water cutoff performance for preventing rainwater or the like from permeating to an area below a single layer of pavement, water permeability sufficient for draining rainwater to an area above the single layer of pavement and sufficient noise reduction performance, through one time of construction, and a pavement method utilizing the same.SOLUTION: Porous concrete to be used for paving a road is characterized in containing coarse aggregates of 1000 to 2000 kg per 1 m, sand of 500 kg or less, cement of 200 to 550 kg, water for such a quantity that a water/cement ratio (W/C) becomes 15 to 50%, and thixotropy additive of which the evaporation residue is 0.5 to 20% with respect to a cement mass.

Description

  The present invention relates to concrete used in road paving. More particularly, the present invention relates to porous concrete used in road paving.

Porous concrete is porous concrete having a small amount of fine aggregate of concrete, and has a large gap, and therefore has excellent noise reduction performance. Therefore, porous concrete is used for low-noise pavement for preventing road noise.
In addition, porous concrete has good water permeability (drainage) because of its large gap, and is also used for water-permeable pavement that quickly infiltrates and reduces rainwater from the gap into the ground. And since rainwater permeates into the pavement layer, the so-called hydroplaning phenomenon can be suppressed.

Here, in permeable pavement, rainwater penetrates to the lower layer of the pavement. For example, on bridge roads, when the pavement layer is made of iron (steel), water reaches the steel region. However, there is a problem of iron rusting and deterioration due to it. Even when the lower pavement layer is made of concrete, deterioration of the concrete due to rainwater penetration is promoted.
Moreover, even when the bottom is the ground, if rainwater permeates the ground, there is a possibility that the ground may be deformed or the soil may flow out.
Therefore, basically, it is not preferable that water passes through the ground below on a road with a large amount of automobile traffic.
On the other hand, it is also conceivable to form a water-impervious layer having a good water-impervious property on an iron or concrete area on the bridge or directly above the ground, and to construct a porous concrete pave on the water-impervious layer. In addition, labor and cost are required for both the construction of the water shielding layer and the construction of the porous concrete.

As another conventional technique, for example, a water-impervious layer is constructed, a surface layer portion having high water permeability is constructed above the water-impervious layer, and road rainwater is permeated only into the surface layer portion along the impermeable layer. A technique for draining has been proposed (see Patent Document 1).
However, in the related art (Patent Document 1), since both the water shielding layer and the surface layer portion must be constructed, labor and cost become very large.

In addition, after applying concrete with high water barrier properties, the surface layer is covered with a layer of a setting retarder that delays the setting reaction of cement, and after the curing period, the surface mortar is scraped off to expose the aggregate. It has been proposed (see Patent Document 2).
However, in the related art (Patent Document 2), since the aggregate is exposed and the gap is formed is limited to the vicinity of the surface layer portion, the water permeability sufficient for draining rainwater and the sufficient noise It is difficult to obtain reduced performance.

Japanese Patent Laid-Open No. 2001-31481 JP-A-10-88507

  The present invention has been proposed in view of the above-mentioned problems of the prior art, and rainwater and the like are infiltrated into an area below the pavement (for example, an iron or concrete area or ground on a bridge) by a single construction. An object of the present invention is to provide a porous concrete that can realize a sufficient water permeability and sufficient noise reduction performance for draining rainwater, and a paving method using the same. In other words, an object of the present invention is to provide a porous concrete and a pavement method capable of realizing both water shielding and water permeability by a single pavement.

Porous concrete of the present invention is a porous concrete for use in paving roads, and coarse aggregate (porous concrete) 1 m ³ per 1000Kg～2000kg, the following sand 500 kg, and cement 200Kg～550kg, water-cement It is characterized by containing an amount of water with a ratio (W / C) of 15% to 50% and a thixotropic additive having an evaporation residue of 0.5% to 20% with respect to the cement mass. .

  In the present invention, the water content is preferably such that the water cement ratio (W / C) is 45% or less.

The pavement method using the porous concrete of the present invention,
1000 kg to 2000 kg of coarse aggregate per 1 m ³ (of porous concrete), 500 kg or less of sand, 200 kg to 550 kg of cement, water with a water-cement ratio (W / C) of 15% to 50%, and cement mass Supplying a porous concrete containing a thixotropic additive having an evaporation residue of 0.5% to 20% on the road,
Spreading and leveling the porous concrete supplied on the road;
A step of compacting the porous concrete supplied on the road;
It is characterized by having.

  In the pavement method of the present invention, it is preferable that a step of applying vibration to the compacted concrete is provided after the compacting step.

According to the present invention having the above-described configuration, 1000 kg to 2000 kg of coarse aggregate per 1 m ^{3 of} porous concrete, 500 kg or less of sand, 200 kg to 550 kg of cement, and a water cement ratio (W / C) of 15 It contains 50% to 50% water and a thixotropic additive with an evaporation residue of 0.5% to 20% with respect to the cement mass. Then lose the liquidity.
For this reason, when the porous concrete (raw concrete) of the present invention is supplied on the road, leveled, and compacted, vibration is added, and its fluidity is improved. As a result, the mortar content (Mm) moves downward, and the coarse part (Mk) occupies most of the surface layer side (Ca), and voids are formed between the coarse aggregates (Mk). The

Here, in the porous concrete of the present invention having the above-described composition, even when the fluidity is high, the mortar content (Mm) remains on the surface of the coarse aggregate (Mk), and the mortar content (Mm) Coarse aggregates (Mk) are bonded together.
Therefore, according to the present invention, the surface layer portion side of the porous concrete has a large gap and good noise reduction performance and water permeability (drainage), as in the case of conventional porous concrete.

On the other hand, when the porous concrete of the present invention is supplied on the road, spread and compacted, the ready-mixed concrete (Cn) is in a highly fluid state, and the mortar content (Mm) moves downward due to gravity ( Settling). Therefore, the lower side (bottom side; for example, the iron region on the bridge or the ground side) is filled with voids of the coarse aggregate (Mk) with mortar (Mm) having high fluidity, so-called “solid” state. It becomes.
Then, after the paving work is finished, if the porous concrete is in a stationary state during the curing period, the pavement layer of the road paved in the present invention is the region below (for example, the iron region on the bridge or the ground side) The mortar layer demonstrates high water barrier properties.

Therefore, according to the present invention, the water that has permeated the region having high water permeability on the surface layer side does not permeate the region having high water shielding properties on the lower side (for example, an iron region on the bridge or the ground side).
For this reason, for example, on a bridge road, water does not reach an area composed of iron below the pavement layer, and deterioration due to iron rusting is prevented. Further, even when the bottom is the ground, water does not reach the ground, so that deformation of the ground, outflow of soil, and the like are prevented.

Here, according to the present invention, only by paving with the above-mentioned porous concrete, the noise reduction performance and water permeability (drainage) on the surface layer side, and the lower side (for example, the iron region on the bridge or the ground side) Can be achieved at the same time. That is, according to the present invention, both water shielding and water permeability can be realized by a single pavement.
Therefore, unlike the prior art described above, it is not necessary to divide the water-permeable layer and the water-permeable layer in two steps.
As a result, it is possible to realize a paved road having both noise reduction performance and water permeability (drainage) and water impermeability while greatly reducing labor and cost required for road paving.

It is sectional drawing which shows the state which the porous concrete which concerns on embodiment of this invention hardened. It is explanatory drawing which shows an example of the construction procedure of the porous concrete which concerns on embodiment. It is explanatory drawing which shows the other example of the construction procedure of the porous concrete which concerns on embodiment. It is explanatory drawing which shows another example of the construction procedure of the porous concrete which concerns on embodiment. FIG. 6 is an explanatory diagram showing an experimental result of Experimental Example 1. It is explanatory drawing which shows the experimental result of Experimental example 2. FIG. It is explanatory drawing which shows the experimental result of Experimental example 4. It is explanatory drawing which shows the experimental result of Experimental example 5. FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
The composition of the porous concrete according to the embodiment, the coarse aggregate 1 m ³ per 1000～2000Kg, sand 1 m ³ per 0～500Kg, cement is 1 m ³ per 200～550Kg, water-cement ratio (W / C) is (Mass ratio) 15 to 50%, and the evaporation residue (mass ratio) of the thixotropic additive to the cement is 0.5 to 20%. In addition to these, an AE water reducing agent or the like is appropriately added.
Table 1 shows the composition of the porous concrete according to the embodiment.
Table 1

Here, the content of cement is preferably 250 to 550 kg, for example, if it is a roadway and a sidewalk. And if it is for revetment and greening, it is good to set it as 200-350 kg, for example.
The water-cement ratio (W / C) is preferably 15 to 35% for a roadway, for example. If it is a sidewalk, for example, 25 to 45% is preferable. Furthermore, for revetment / greening, for example, 25 to 45% is preferable.
As a thixotropic additive, it is preferable to add 6-8% of an acrylic emulsion.
Here, the thixotropic additive is a material that imparts thixotropy to a mixture (for example, concrete) by adding to the concrete, for example. That is, by adding a thixotropic additive, the fluidity of the mixture increases in a state where vibrations are added to the mixture (for example, concrete) (including when it flows). On the other hand, when the state to which vibration or the like is applied (including the time of flowing) is completed and the mixture becomes stationary, the fluidity of the mixture is lost.
As the thixotropic additive, a commercially available material (for example, a trade name “Cybinol” (X-209-074E series) of Seiden Chemical Co., Ltd. is preferable) can be used.

In Table 1, the AE water reducing agent is a material having both the characteristics of the AE agent and the characteristics of the water reducing agent.
AE agent refers to an air entraining agent that uniformly entrains the air content in the concrete as fine air bubbles, making the concrete workability (working, placing, compacting, finishing, etc. without material separation) Performance) and the like.
A water reducing agent means a dispersant for cement particles. The water reducing agent is adsorbed on the interface of the cement particles, disperses the cement particles by electrostatic repulsion, and increases fluidity.

In the composition of Table 1, No. 3 coarse aggregate to No. 7 coarse aggregate are used as the coarse aggregate.
No. 5 coarse aggregate (particle size 13 mm to 20 mm), No. 6 coarse aggregate (particle size 5 mm to 13 mm), No. 7 coarse aggregate (particle size 5 mm to 2.5 mm) are mainly used, but No. 4 coarse Aggregate (particle size 20 mm to 30 mm), No. 3 coarse aggregate (particle size 30 mm to 40 mm) can also be used.
For road paving, coarse aggregates with a maximum dimension of 5 mm to 20 mm are mostly used. In addition, as a revetment and greening base, there is also the use of coarse aggregate having a maximum dimension of 40 mm.

FIG. 1 shows a state in which porous concrete according to the embodiment (porous concrete having a composition shown in Table 1) is applied to road pavement and hardened (cross section of the porous concrete pavement).
In FIG. 1, the cross-section of the paved road made of porous concrete according to the embodiment is composed of a surface layer portion indicated by reference character Ca and a bottom portion indicated by reference character Cb.

In the surface layer portion Ca, the coarse aggregates Mk are bonded by mortar Mm. Here, in the surface layer portion Ca, the mortar Mm covers the surface of the coarse aggregate Mk in the form of a coating film.
Since the mortar Mm exists in the form of a coating on the surface of the coarse aggregate Mk, and the coarse aggregate Mk is bonded to each other by the coating-like mortar Mm, the surface layer portion Ca is porous as a whole and is porous. And has good water permeability.
On the other hand, at the bottom Cb, the mortar Mm is densely filled into the gaps between the coarse aggregates Mk, and exhibits sufficient water shielding properties.

An example of the laying procedure in the porous concrete having the composition shown in Table 1 is shown in FIG.
In the procedure shown in FIG. 2, a so-called “earthwork section” is constructed by a machine. Although it is constructed in the same procedure as the mechanical construction in the case of conventional porous concrete laying, it is different from the conventional porous concrete laying in that the step of applying vibration is executed as necessary.

In FIG. 2, in the process (procedure) indicated as “prepared concrete supply process”, the agitator car (concrete mixer truck) 1 kneads the ready-mixed concrete material having the composition shown in Table 1 at the tip of the construction site. Transport to. And the ready-mixed concrete Cn is dropped on the road surface of the said construction location.
The ready-mixed concrete Cn dropped on the road surface is roughly stretched across the entire width direction on the road surface of the construction site by, for example, the tire shovel 2 having the shovel 21.
Although illustration is omitted, a backhoe may be used in place of the tire shovel 2 when the ready-mixed concrete Cn is roughly extended over the entire road surface width direction.

In FIG. 2, in the process (procedure) indicated as “laying and compacting process”, the ready-mixed concrete 3 is roughly stretched over the entire width direction of the road surface by the asphalt finisher 3. By repeating forward and backward, it is spread and compacted.
Here, ready-mixed concrete may be directly supplied from the agitator wheel 1 to the asphalt finisher 3.

In FIG. 2, an external force acts on the ready-mixed concrete Cn in the process (procedure) indicated as “ready concrete supply process” and the process indicated as “laying and compacting process”. In addition, vibration is always applied to the ready-mixed concrete Cn (added with a thixotropic additive) having the composition shown in Table 1. Therefore, the fluidity of the ready-mixed concrete Cn having the composition shown in Table 1 is improved, and the mortar Mm (see FIG. 1) descends (sinks) in the gaps of the coarse aggregate Mk. And it moves to the bottom part Cb side of FIG.
In FIG. 2, the process (procedure) indicated as “ready concrete supply process” and the process (procedure) indicated as “laying / compacting process” are finished, and ready concrete Cn is allowed to stand. Then, vibration is not added. Therefore, the mortar Mm moved to the bottom Cb side in FIG. 1 is reduced in fluidity and solidified in a state where the coarse aggregate Mk is dense.

As a result, on the upper layer side (surface layer portion Ca in FIG. 1) where the ready-mixed concrete Cn is placed, the coarse aggregate Mk is joined only in part, the gap between the coarse aggregate Mk becomes a space, and is porous. A (porous) permeable layer is formed.
On the other hand, below the middle layer of the construction area where the ready-mixed concrete Cn is cast (bottom Cb in FIG. 1), the gap between the coarse aggregates Mk is filled with nectar with mortar Mm to form a water-impervious layer with extremely low permeability. Is done.
In FIG. 2, after a “laying and compacting step”, when a predetermined curing period has elapsed, a porous concrete pavement as shown in FIG. 1 is completed.

Here, depending on various construction conditions (for example, temperature, concrete composition, etc.), the flowability of the mortar Mm is insufficient, and the mortar Mm is sufficiently moved from the surface layer portion Ca to the bottom portion Cb side in FIG. In the surface layer portion Ca, the mortar Mm remains in the gap between the coarse aggregates Mk, the sedimentation to the mortar Mm on the bottom Cb side is not sufficient, and the gap between the coarse aggregates Mk is sufficiently filled with the mortar Mm. There are cases where this is not done.
In such a case, the vibrating concrete 4 and the vibrating plate 5 are used to supplementarily vibrate the ready-mixed concrete Cn, thereby promoting the thixotropy effect and maintaining a high fluidity of the mortar Mm. It is also possible.

FIG. 3 shows a construction procedure (construction method) different from FIG.
In the construction procedure of FIG. 2, a so-called “earthwork section” is constructed by a machine (tire excavator, asphalt finisher), but in FIG. 3, the earthwork section is constructed by human power.
In the procedure (process) indicated as “raw concrete supply process” in FIG. 3, the agitator car (concrete mixer car) 1 has the composition shown in Table 1 as described with reference to FIG. While kneading the concrete material, it is transported to the construction site, and the ready-mixed concrete Cn is dropped onto the road surface of the site.

Next, in the procedure (process) indicated as “fresh concrete supply / laying process” in FIG. 3, the entire area where the fresh concrete Cn is laid by human power using the so-called “dragonfly” 6, scoop 7 and rake 8. Spread over and spread.
In FIG. 3, as in FIG. 2, when the fluidity of cement is insufficient due to various conditions, vibration is supplementarily applied to the ready-mixed concrete using the vibration roller 4 and the vibration plate 5. The fluidity can be improved by the thixotropic effect.
In FIG. 3, the configuration and operational effects other than those described above are the same as those described in FIG.

FIG. 4 also shows a construction procedure (construction method) for porous concrete, and shows a construction procedure (construction method) different from those in FIGS. 2 and 3.
In FIG. 4, two parallel rails R are laid so as to cover the entire width direction of the road in the construction area. And the concrete spreader 11 is arrange | positioned on the starting point (right end of FIG. 4) of the rail R. As shown in FIG.
The concrete Cn having the composition shown in Table 1 is supplied by the agitator vehicle 1 in the procedure indicated as “concrete supply process” in FIG.

In the procedure labeled “concrete leveling step” in FIG. 4, the concrete spreader 11 spreads the concrete Cn over the entire width of the construction area.
When the concrete Cn is spread by a predetermined distance in the traveling direction (left side in FIG. 4), the concrete finisher 12 is arranged behind the concrete spreader 11 (right side in FIG. 4).

In the procedure shown in FIG. 4 as “compacting / rough finishing process”, the concrete finisher 12 performs concrete compacting and rough finishing over the entire width direction of the construction area.
When the progress of the “concrete leveling process” has progressed by a predetermined amount, a concrete leveler 13 is arranged behind the concrete finisher 12 in the rail R.

Next, the procedure labeled “Flat finishing step” in FIG. 4 is executed. In such a procedure, the concrete leveler 13 performs the flat finishing of the concrete over the entire width direction of the construction area.
When the settling of the mortar Mm (see FIG. 1), which is initially planned, into the gap between the coarse aggregates Mk (see FIG. 1) is not sufficient due to various conditions, the “vibration adding step” is displayed in FIG. You can perform the steps you have. In such a procedure, vibration is supplementarily applied to the laid raw concrete Cn using the vibration roller 4 and the vibration plate 5 to improve the fluidity of the concrete Cn or the mortar Mm by the thixotropy effect.
In FIG. 4, configurations and operational effects other than those described above are the same as those described with reference to FIGS. 2 and 3.

Next, the property of the porous concrete which concerns on embodiment mentioned above is demonstrated.
Such properties are confirmed by Experimental Examples 1 to 5.
Hereinafter, Experimental Examples 1 to 5 will be described.

表３

[Experimental Example 1]
In Experimental Example 1, the strength of the porous concrete according to the illustrated embodiment was confirmed by a bending test.
The materials and blends used in Experimental Example 1 are shown in Tables 2 and 3.
Table 2

Table 3

As shown in Table 2, tap water was used as the material water (W), and ultra-high strength cement was used as the cement 1 (C). The thixotropy additive was added as a special additive (MA), the fine aggregate was fine sand (S), and crushed stone 6 (G1) and crushed stone 7 (G2) were used as the coarse aggregate.
Regarding the detailed blending of the porous concrete according to the embodiment of Table 3, the values of the conventional commercially available porous concrete are also described at the same time (lower stage) as a comparative material.
In both experimental subjects, the water cement ratio W / C is 27.5%.
Various symbols in Table 3 are as described as “abbreviations” in Table 2.
In Tables 2 and 4, the high-performance AE water reducing agent is a known drug (trade name “Reobuild SP8SV” manufactured by BASF Pozzolith Co., Ltd.).

The experimental result (bending strength) of Experimental Example 1 is shown in FIG. In FIG. 5, the bending test result of the conventional commercially available porous concrete is compared with the bending test result of the porous concrete (porous concrete according to the embodiment) whose materials and blends are shown in Tables 2 and 3. .
As test materials (samples), three samples of the porous concrete according to the embodiment and the conventional commercially available porous concrete were tested.
As shown in FIG. 5, the average value of the bending strength of the commercially available porous concrete was 6.31 N / mm ² , whereas the average value of the porous concrete according to the embodiment was 8.59 N / mm ^2. It was confirmed that the bending strength was greatly improved (36% increase).

表５

[Experiment 2]
In Experimental Example 2, a labeling test was conducted to confirm the surface wear resistance of the porous concrete.
The labeling test of Experimental Example 2 is performed on two specimens (specimen No. 1 and specimen No. 2) made of porous concrete (porous concrete according to the embodiment) whose materials and blends are shown in Tables 4 and 5. The test was carried out according to “Handbook of Pavement Survey Test Method: B002”.
The materials and blends used in Experimental Example 2 are shown in Tables 4 and 5. Here, the mass per 1 m ^{3 of} each material is shown in Table 5.
Table 4

Table 5

The symbols shown in Table 5 are as described in “Abbreviations” in Table 4.
As shown in Table 4, tap water was used as the material water (W), and ultra-high strength cement was used as the cement 1 (C). The thixotropy additive was added as a special additive (MA). Fine aggregate was fine sand (S), and coarse aggregate was crushed stone 6 (G).
The water cement ratio W / C is 27.5%.

The result of Experimental Example 2 is shown in FIG.
Specimen No. 1. Specimen No. The average value of wear amount (wear amount) of ² is 0.45 cm ^{2, and} 1.3 cm ² (for example, the setting value of Hokkaido Development Bureau Road Design Guidelines), which is the standard value of asphalt pavement wear amount, is increased. It is below.
Specimen No. 1. Specimen No. The wear amount of ² is much less than 1.3 cm ² .
From this, it was confirmed that the porous concrete according to the embodiment exhibits sufficient wear resistance when used for road pavement.

[Experiment 3]
In Experimental Example 3, a water permeability test was performed to confirm the surface water permeability of the porous concrete according to the embodiment and the water impermeability at the bottom.
The water permeability test of Experimental Example 3 was performed on four types of blends shown in Table 6. In other words, Experimental Example 3 was performed on porous concrete (mixing 1 to mixing 4) according to four types of mixing within the range of Table 1 in the illustrated embodiment.
Table 6 shows the formulations used in Experimental Example 3.
Table 6

The water permeability test of Experimental Example 3 was performed according to “Handbook of Pavement Survey Test Methods: B012, B017T”.
As shown in Table 6, the water cement ratio W / C in Formulations 1 to 4 is 27.5%.
The results of Experimental Example 3 are shown in Table 7.
Table 7

In Table 7, in each of Formulation 1 to Formulation 4, the upper (upper) row shows the results in the surface layer portion (water permeable layer: Ca in FIG. 1) of the porous concrete according to the embodiment. Then, the lower row (lower portion) shows the result at the bottom of the porous concrete according to the embodiment (water shielding layer: Cb in FIG. 1).
As shown in Table 7, the water permeability coefficient of the surface layer portion (water permeable layer: Ca in FIG. 1) is significantly higher than 1.0 × 10 ⁻² cm / s in any formulation, and good water permeability is obtained. confirmed.
On the other hand, the water permeability of the bottom portion (water-impervious layer: Cb in FIG. 1) was “0” in any formulation, and sufficient water impermeability (water-impervious) was confirmed.

[Experimental Example 4]
In Experimental Example 4, a tire drop test was performed to confirm the noise reduction performance of the porous concrete according to the embodiment.
Here, in the rotating tire drop test, a rotated tire (size is 185 / 70R13, air pressure is 200 kPa, rotation speed is equivalent to 20 km / h) is freely dropped from a height of 4 m, and the tire is measured (porous). The sound pressure level when contacting the surface of the concrete was measured.
The measurement was performed five times with the same specimen, and an average value of three data excluding the maximum value and the minimum value was adopted.

In Experimental Example 4, in addition to the porous concrete according to the embodiment, a dense particle size asphalt mixture (hereinafter referred to as “dense particle size AS”) having an aggregate maximum particle size of 13 mm, an aggregate maximum particle size of 13 mm, and a porosity of 20% The porous asphalt mixture (hereinafter referred to as “drainage AS”) was also tested.
The result of Experimental Example 4 is shown in FIG.

As shown in FIG. 7, the noise value of the dense particle size AS was 86.4 dB, and the noise value of the drainage AS was 77.5 dB. And the noise value of the porous concrete which concerns on embodiment was 77.9 dB.
From the experimental results shown in FIG. 7, the porous concrete according to the embodiment has a noise reduction effect significantly improved compared to the dense grain size AS, and has a noise reduction effect comparable to the drainage AS, which is considered to have a large noise reduction effect. It has been confirmed that it works.

[Experimental Example 5]
In Experimental Example 5, a sagging performance experiment was performed in a fresh state, and the thixotropy and material separation resistance of the porous concrete according to the embodiment were confirmed.
As described above, thixotropy is a property in which fluidity increases when vibration is applied, and loses fluidity in a stationary state.
Here, the sag test was performed for both the static sag test and the dynamic sag test.

The static sag test was performed according to the following procedure.
(1) Put the kneaded concrete material (mass about 2kg) on a 2.36mm sieve and let stand for 1 minute.
(2) After resting, measure the mass of the stale mortar.
Here, “sag” means that the paste or mortar settles down. The “sagging mortar” means the mortar that has settled down.
(3) The static sag rate is obtained by the following formula.
Static sag rate (%)
= Sag after vibration / Concrete mass before vibration (about 2kg) x 100

The dynamic sag test was performed according to the following procedure.
(1) Put the kneaded concrete material (mass: about 2 kg) in a 4.75 mm sieve and vibrate with a flat vibrator (vibrating plate; see FIG. 2) for 30 minutes.
(2) After vibration, measure the mass of the stale mortar.
(3) The dynamic sag rate is obtained by the following formula.
Dynamic sag rate (%)
= Sag after vibration / Concrete mass before vibration (about 2kg) x 100

The sagging test of Experimental Example 5 was performed on four types of blends shown in Table 8. In other words, Experimental Example 5 was performed on porous concrete (mixing 1 to mixing 4) according to four types of mixing within the range of Table 1 in the illustrated embodiment.
Table 8

In Table 8, the water cement ratio W / C of the other blends is 27.5% except that the water cement ratio W / C of the blend 3 is 32.5%.
The test result of Experimental Example 5 is shown in FIG.
In FIG. 8, as a result of the dynamic sag test, the sag rate of Formulation 1 was the lowest, 10%, and the others were 12-13%.
On the other hand, in the static sag test, there is almost no settling (sagging) of the paste or mortar in the lower part (0.2% for compounding 2 and 0% for the other). It was confirmed that drooping) occurred.
From Experimental Example 5, it was confirmed that the porous concrete according to the embodiment did not sag immediately after stirring with a mixer or an agitator vehicle, and generated sag due to vibration during compaction work after completion of laying. .

Next, with reference to Experimental Example 6 to Experimental Example 12, the upper limit value and lower limit value of each component in the formulations shown in Table 1 will be verified.
In Experimental Examples 6 to 12, the contents of the porous concrete used as the material other than the materials indicated by a plurality of numerical values are the same. In other words, in Experimental Example 6 to Experimental Example 12, in the composition shown in Table 9, the content of any one kind of material is changed.
Table 9

In Table 9, the contents of coarse aggregate, sand and cement are numerical values when converted to 1 m ³ of porous concrete.
As shown in Table 9, as the base specimen, the amount of coarse aggregate per 1 m ³ was 1500 kg, the amount of sand was 300 kg, and the amount of cement was 300 kg. The water-cement ratio (W / C) was 30%, and the thixotropic additive had an evaporation residue amount of 7% with respect to the cement mass.

[Experimental Example 6]
In Experimental Example 6, the lower limit value of the coarse aggregate in the porous concrete according to the embodiment is verified.
In the blending shown in Table 9, five types of samples were prepared by varying the blending amount of the coarse aggregate by 20 kg in a range of 960 kg to 1040 kg per 1 m ³ of porous concrete.
With respect to these five types of samples, a water permeability test similar to Experimental Example 3 and a tire drop test similar to Experimental Example 4 were performed.
The results of Experimental Example 6 are shown in Table 10.
Table 10

In Table 10, “◯” means that the necessary water permeability and noise reduction were confirmed, and “×” means that the necessary level of water permeability and noise reduction could not be confirmed. ing.
From Table 10, it was confirmed that the lower limit value of the amount of the coarse aggregate was 1000 kg per 1 m ^{3 of} porous concrete because necessary levels of water permeability and noise reduction were exhibited.
Coarse aggregate amount of coarse aggregate is less than porous concrete 1 m ³ per 1000 kg, for the amount of coarse aggregate is small, even less parts coarse aggregate in the surface of the porous concrete is exposed (within mortar Therefore, it is presumed that necessary water permeability and noise reduction performance cannot be exhibited.

[Experimental Example 7]
In Experimental Example 7, the upper limit value of the coarse aggregate in the porous concrete according to the embodiment was verified.
In the blending shown in Table 9, five types of samples were prepared by varying the blending amount of the coarse aggregate by 20 kg in a range of 1960 kg to 2040 kg per 1 m ³ of porous concrete.
With respect to these five types of samples, whether or not compaction is possible was verified in the same manner as that applied to roads.
The results of Experimental Example 7 are shown in Table 11.
Table 11

In Table 11, “◯” means that compaction was possible, and “x” means that compaction was not possible.
From Table 11, it was confirmed that the upper limit of the amount of the coarse aggregate was 2000 kg per m ^{3 of} porous concrete in order to perform compaction in the same manner as that applied to the road.
Amount of coarse aggregate, if it exceeds the porous concrete 1 m ³ per 2000kg is coarse aggregate amount is too large, it becomes impossible to compaction.

[Experimental Example 8]
In Experimental Example 8, the proper blending of sand in the porous concrete according to the embodiment is verified.
In the blending shown in Table 9, five types of samples were prepared by varying the blending amount of sand by 20 kg in a range of 460 kg to 540 kg per 1 m ³ of porous concrete.
The five types of samples were subjected to the same water permeability test as in Experimental Example 3, and the water impermeability at the bottom of the porous concrete was confirmed.
The results of Experimental Example 8 are shown in Table 12.
Table 12

In Table 12, “◯” means that the required level of water shielding at the bottom could be confirmed, and “×” did not demonstrate the required level of water shielding at the bottom. Means.
From Table 12, it was confirmed that the amount of sand per 1 m ^{3 of} porous concrete should be 500 kg or less.
When sand is added to 520 kg or more, it is estimated that even if the thixotropy is improved, the component that sinks downward due to vibration is reduced, and the water-imperviousness at the bottom cannot be secured.

[Experimental Example 9]
In Experimental Example 9, the lower limit value of the water cement ratio (W / C) in the porous concrete according to the embodiment is verified.
In the formulation shown in Table 9, the value of W / C was varied by 1% in a range of 11% to 15% to prepare five types of samples.
The five types of samples were subjected to the same bending test as in Experimental Example 1 to verify the bending strength.
The results of Experimental Example 9 are shown in Table 13.
Table 13

In Table 13, “◯” means that the required level of bending strength has been confirmed, and “×” means that the required level of bending strength at the bottom is not provided. .
As can be seen from Table 13, all of the five types of samples having W / C values of 11% to 15% exhibited the required bending strength.
Although not explicitly shown in Table 13, the bending strength of the samples with W / C values of 11% to 14% for the five types of samples in Table 13 is compared with the bending strength of the sample with W / C of 15%. , Did not increase significantly.
That is, even if the cement ratio was increased until the water cement ratio W / C was 14% or less, no significant improvement in strength was confirmed. From this point of view and the viewpoint of reducing (saving) the amount of cement used, it was determined that a lower limit of W / C was 15%.

[Experimental Example 10]
In Experimental Example 10, the upper limit value of the ratio of concrete to water (W / C) in the porous concrete according to the embodiment is verified.
In the formulation shown in Table 9, 9 types of samples were prepared by varying the numerical value of W / C by 1% within a range of 44% to 52%.
For these nine types of samples, the peel strength of the aggregate on the surface side of the porous concrete (the side on which the aggregate appears) was verified.
The results of Experimental Example 10 are shown in Table 14.
Table 14

In Table 14, “◯” means that the minimum necessary level of aggregate peel strength was confirmed on the road surface, and “◎” means that the aggregate peel strength was good. "X" means that the required level of aggregate peel strength could not be exhibited.
As is clear from Table 14, when the W / C value exceeds 50%, the strength cannot be secured. From this, it was confirmed that the upper limit value of W / C should be 50%.
When the value of W / C exceeds 50%, the cement content decreases, and in particular, the strength on the porous (porous) surface layer side (road surface side: Ca side in FIG. 1) is not sufficient, and the surface It is estimated that the scattering of aggregates becomes a problem.
In Table 14, it was confirmed that the W / C was particularly suitable when it was 45% or less.

[Experimental Example 11]
In Experimental Example 11, the lower limit value of the addition amount of the thixotropic additive is verified.
In the formulation shown in Table 9, five types of samples were prepared by varying the amount of thixotropic additive added by 0.1% within a range of 0.3% to 0.7% of the evaporation residue relative to the cement mass. did.
For these five types of samples, it was confirmed whether or not the fluidity changed before and after the addition of vibration.
The results of Experimental Example 11 are shown in Table 15.
Table 15

In Table 15, “◯” indicates that the flowability of the porous concrete was improved after the vibration was applied and the thixotropy was exhibited, and “X” means that the thixotropy was not exhibited.
As apparent from Table 15, when the amount of the thixotropic additive added is 0.4% or less in terms of the evaporation residue relative to the cement mass, the thixotropic property was not exhibited.
From this, it was confirmed that the lower limit of the addition amount of the thixotropic additive should be 0.5%.

[Experimental example 12]
In Experimental Example 12, the upper limit value of the addition amount of the thixotropic additive is verified.
In the formulation shown in Table 9, five types of samples were prepared by varying the addition amount of the thixotropic additive in increments of 1% within a range of 19% to 23% of the evaporation residue with respect to the cement mass.
For the five types of samples, the thixotropy was verified in the same manner as in Experimental Example 11.
The results of Experimental Example 12 are shown in Table 16.
Table 16

In Table 16, “◯” indicates that the porous concrete exhibited thixotropy, which is a property that hardens after vibration addition, and “x” indicates that thixotropy was not exhibited.
As is apparent from Table 16, all of the five types of samples exhibited thixotropic properties.
Here, although not explicitly shown in Table 16, there is a significant difference in thixotropy regarding the amount of the thixotropic additive added to the four types of samples in which the evaporation residue with respect to the cement mass is 20% to 23%. I didn't. From that and the viewpoint of cost reduction (saving), the upper limit of the addition amount of the thixotropic additive was determined to be 20% of the evaporation residue with respect to the cement mass.

As described above, the porous concrete according to the illustrated embodiment contains a thixotropic additive having an evaporation residue of 0.5% to 20% with respect to the cement mass. Increases and loses fluidity when at rest.
As shown in FIG. 2, when the material is kneaded in the agitator vehicle 1, the fluidity is increased, and when the work is supplied onto the road, spread and compacted, the porous concrete according to the illustrated embodiment is , Its fluidity is further improved.
In porous concrete with improved fluidity, the mortar content Mm (see FIG. 1) moves downward (sinks), and the coarse aggregate Mk occupies most of the surface layer Ca side. A gap is formed between them. In other words, in the surface layer portion Ca, the mortar content Mm remains only on the surface of the coarse aggregate Mk, and the coarse aggregate Mk is partially bonded by the mortar content Mm. Therefore, on the surface layer portion Ca side, like the conventional porous concrete, the gap is increased, the water permeability (drainage) is improved, and the noise reduction performance is also improved.

In addition, as described above, in the porous concrete according to the illustrated embodiment, the mortar content Mm of the ready-mixed concrete Cn, which is in a state of high fluidity when supplied onto the road, leveled, and compacted, The bottom Cb (see FIG. 1, for example, an iron region on the bridge or the ground side) is filled with a gap of the coarse aggregate Mk with mortar Mm having high fluidity. The It becomes a so-called “solid” state.
Then, after the pavement work is completed, if the porous concrete is in a stationary state during the curing period and the fluidity decreases, the road pavement layer according to the illustrated embodiment is located underneath (for example, an iron region on the bridge or a ground side). In the region of), since the voids of the coarse aggregate Mk are filled with the mortar Mm in a so-called “solid” state, the solid mortar layer exhibits a high water barrier.
Accordingly, the water that has permeated into the high water permeability region on the surface layer portion Ca side is blocked by the high water barrier region on the bottom Cb side, and does not permeate, for example, the iron region on the bridge or the ground. Therefore, for example, in a bridge road, deterioration due to iron rusting is prevented in an area composed of iron below the pavement layer. Moreover, when the bottom is the ground, the deformation of the ground, the outflow of soil, and the like are prevented.

Here, according to the porous concrete according to the embodiment, the noise reduction performance and water permeability (drainage) on the surface layer portion Ca side, and the bottom portion Cb side (for example, on the bridge) only by performing construction as shown in FIG. Water shielding of the steel area and the ground side) can be achieved at the same time.
In other words, unlike the prior art, there is no need to work in two steps: construction of a layer having water-impervious properties and construction of a layer having water permeability.
As a result, it is possible to realize a paved road having both noise reduction performance and water permeability (drainage) and water impermeability while greatly reducing labor and cost required for road paving.

  The illustrated embodiment is merely an example, and is not intended to limit the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Agitator wheel 2 ... Tire excavator 3 ... Asphalt finisher 4 ... Vibration roller 5 ... Vibration plate 6 ... Dragonfly 7 ... Scoop 8 ... Rake 9 ... Iron Net 11 ... Concrete spreader 12 ... Concrete finisher 13 ... Concrete leveler Ca ... Upper layer Cb ... Bottom Cn ... Ready-mixed concrete Mm ... Mortar Mk ... Coarse bone Material

Claims (4)

In porous concrete for use in paved roads, and coarse aggregate 1000kg~2000kg per 1 m ^3, and less sand 500 kg, and cement 200Kg～550kg, the amount of water water-cement ratio of 15% to 50% And a porous concrete containing a thixotropic additive having an evaporation residue of 0.5% to 20% with respect to the cement mass.   The porous concrete according to claim 1, wherein the water content is such that the water-cement ratio is 45% or less. 1000 kg to 2000 kg of coarse aggregate per 1 m ³ , 500 kg or less of sand, 200 kg to 550 kg of cement, water with a water-cement ratio (W / C) of 15% to 50%, and evaporation residue relative to the cement mass Supplying porous concrete containing thixotropic additive of 0.5% to 20% on the road;
Spreading and leveling the porous concrete supplied on the road;
A step of compacting the porous concrete supplied on the road;
A pavement method using porous concrete, characterized by comprising:   The pavement method according to claim 3, further comprising a step of applying vibration to the compacted concrete after the compacting step.

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