CN111877083A

CN111877083A - Load-bearing geopolymer base water storage road

Info

Publication number: CN111877083A
Application number: CN202010792593.5A
Authority: CN
Inventors: 曹容川; 方正
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-08-11
Filing date: 2020-08-11
Publication date: 2020-11-03

Abstract

The invention provides a novel road concept different from the traditional sponge city mode at present, namely a bearable water storage road (a bearable geopolymer base layer water storage road). The road structure comprises a permeable asphalt layer, a permeable concrete layer, a geopolymer water storage layer and a cement concrete lower sealing layer from top to bottom; there is cement concrete limit seal at road structure limit portion, and cement concrete limit seal bottom sets up drainage valve. The geopolymer aquifer gel material is geopolymer gel, and the aggregate is open-graded coarse aggregate(ii) a The geopolymer gel is prepared from aluminum silicon oxide (Si)₂O₅，Al₂O₂) Mixing with an alkali activator, wherein the molar ratio of elements to compounds in the gel is as follows: 1.8 to 2.5 of Si/Al, 0.8 to 1.2 of Al/Na, and H₂O/Na₂O is 13.5 to 17.0; the compressive strength of the geopolymer water storage layer meets the standards of a highway and a primary road base; the water storage road can bear 9-17 hours of rainfall of heavy rain (50-100 mm/d) under the condition that the municipal drainage system is completely paralyzed.

Description

Load-bearing geopolymer base water storage road

Technical Field

The invention provides a novel road concept different from the traditional sponge city mode, namely a bearable water storage road (the base bearing standard meets the strength requirements of a Chinese expressway and a first-level highway), and the novel sponge city water storage road can bear the rainfall of 50-100 mm/d for 9-17 hours under the condition that a municipal drainage system is completely paralyzed. The core point is that geopolymer is used for replacing cement as a gel material of the water-storing road base layer.

Background

At present, the main modes of sponge cities comprise green roofs, biological detention (wetland gardens and the like) and permeable pavements. The green roof is mainly applied to high-density building cities and is greatly influenced by floors; the biological detention mostly occurs in the form of wetland gardens and concave greenbelts, and the transformation difficulty of old cities is very high; the permeable pavement mainly comprises a non-bearing sidewalk, the water flow terminal is a municipal drainage pipe network, and part of sponge urban communities are also provided with PP water storage modules matched with the permeable pavement for use (still can not bear load). The sponge city has six elements, namely seepage, stagnation, storage, purification, use and discharge. At present, the three main modes of the traditional sponge cities are not all satisfactory in rainwater treatment effect, for example, in summer (2020) in China, large-scale rainfall occurs in Yangtze river basin, very serious flood disasters occur in Jiangxi and the like, so that Wuhan who carries out massive sponge city transformation is concerned, and the condition of road ponding also often occurs. After the traditional sponge city mode is reformed, the city still frequently faces the predicament of flood and ponding, and the main reason lies in that the link of 'storage' has a problem. Green roofs can store very limited rainwater (without connecting large reservoirs); although the bioretention especially the wetland garden can directly collect rainwater, the rainwater collection quantity is greatly influenced by the wetland scale and the wetland depth, and the large-scale wetland garden is difficult to reform in the old city; the rainwater terminal of permeable pavement is still municipal drainage pipe network (some communities have water storage module), and under the condition of heavy rain, rainwater passing through the permeable pavement is difficult to enter the municipal drainage system in a load state.

In summary, the current traditional sponge city model has the following problems: 1. the road cannot store water. After the city is transformed through the traditional sponge city mode, the phenomena of road ponding, flood disasters and the like still frequently occur in the face of heavy rain. 2. The transformation difficulty is high, and the transformation cost is high. 3. And can not bear the weight. Most of the permeable pavements are used for sidewalks or light roads, and the permeable pavements containing the PP water storage modules in communities can hardly reach the bearing standards of primary and secondary roads in cities.

Disclosure of Invention

The invention provides a novel road concept different from the traditional sponge city mode, namely a bearable water storage road (a bearable geopolymer base layer water storage road), and simultaneously describes novel materials and structures of the water storage road. The invention aims to solve the problems that the traditional sponge urban mode road can not store water, has multiple transformation types and complex construction process and can not bear heavy load.

In order to achieve the purpose, the invention adopts the following technical scheme:

a bearable geopolymer base layer water storage road structurally comprises a permeable asphalt layer, a permeable concrete layer, a geopolymer water storage layer and a cement concrete lower sealing layer from top to bottom; there is cement concrete limit seal at road structure limit portion, and there is drainage valve cement concrete limit seal bottom, and drainage valve connects ground polymer water-retaining layer and municipal drainage pipe network (or directly takes out water and utilizes).

The quality standard of the permeable asphalt layer should meet the corresponding specification (CJJ/T190-.

The quality standard of the pervious concrete layer should meet the corresponding specifications (CJJ/T190-2012, CJJ/T135-2009).

The geopolymer aquifer gel material is geopolymer gel (geopolymer after dehydration and polycondensation), the aggregate is open-graded coarse aggregate, and the layer thickness is 300-750 mm.

Further, the geopolymer gel is made of aluminum silicon oxide (Si)₂O₅，Al₂O₂) Mixing with alkali activator.

Further, aluminum silicon oxides are typically prepared by hydrating a polymer with aluminum silicon salts. The aluminosilicate hydrated polymer generally comprises kaolin, clay, waste concrete powder.

Further, the aluminum silicon oxide of the present invention is metakaolin (calcined kaolin).

Further, the preparation method of the alkali activator comprises the following steps: 1. mixing strong alkali powder (NaOH or KOH) and liquid water glass (Na)₂O·nSiO₂). 2. Mixing nano silicon dioxide (SiO)₂) Powder and sodium hydroxide (NaOH) solution. 3. Mixed high-modulus liquid water glassAnd low modulus liquid water glass. The invention uses mixed strong alkali powder (NaOH) and liquid water glass (Na)₂O·nSiO₂) The method.

Further, the formulation of the geopolymer gel depends on the gel aggregate adhesion and final strength (mixture of aggregate and gel); the Molar Ratio (MR) of the elements and compounds in the gel was in the following table 1:

TABLE 1

Si/Al	1.8～2.5
		Al/Na	0.8～1.2
H₂O/Na₂O	13.5～17.0

Furthermore, sodium methyl silicate (CH) with the mass of gel (M) of 1.7-6.8 percent can be added into the geopolymer gel₅SiO₃Na) as a former water repellent and a tackifier (adhering aggregate) and improves the aging resistance and corrosion resistance (CH) of the geopolymer₃-)。

Furthermore, the particle size of the open-graded aggregate is 4.75 mm-10 mm, 10 mm-20 mm, or 16 mm-31.5 mm, and the aggregate accounts for 70% -85% of the total weight (aggregate + geopolymer gel).

The drain valve switch can be controlled (mechanically or electronically), the drain valve can control the water flow of a drainage pipeline, and the drainage pipeline can be a conventional municipal drainage pipeline (concrete pipe (CP) or Reinforced Concrete Pipe (RCP)). The drainage pipeline is arranged to guide water flow into a municipal drainage system (off peak) when the municipal drainage system is not in a load state or directly pump water for utilization.

The cement concrete lower sealing layer is a cement concrete layer (the strength is more than or equal to C35) with the thickness of 10 cm-20 cm, the cement concrete lower sealing layer is laid above the soil foundation, and the contact surface of the cement concrete lower sealing layer and the geopolymer water storage layer is waterproof.

The cement concrete edge sealing layer is a cement concrete layer (the strength is more than or equal to C35) of 10 cm-20 cm, the cement concrete edge sealing layer is positioned at the edge of the road, and the contact surface of the cement concrete edge sealing layer and the road structure is waterproof.

The invention has the beneficial effects that:

the novel concept of the invention, namely the water storage road, does not belong to the traditional sponge city model. Compared with the traditional sponge city mode, the invention has the following advantages:

1. can bear heavy load. The compressive strength of the geopolymer water storage layer is more than 5.5MPa (3-5 MPa for expressways and first-level highways).

2. The road can hold water. The porosity of the geopolymer water-retaining layer is between 28 and 40 percent. The area ratio of the road is 15% (actually, the area ratio is more than 15%, the geopolymer water storage layer can be used for a driving road, a sidewalk, a square and the like), the water storage road can accommodate 9-17 hours of rainfall of rainstorm (50-100 mm/d) under the condition that the municipal drainage network in the city is in a load state and does not work at all, and the whole road base layer serves as an ultra-large reservoir.

3. The construction process is simple. The construction mode of the geopolymer water storage layer is consistent with that of the conventional road cement stabilized macadam. Except that the geopolymer acts as a strong gelling material (instead of cement).

4. Corrosion resistance and long service life. The main chemical bonds of the geopolymer are silicon-oxygen bonds (Si-O) and aluminum-oxygen bonds (Al-O), and the geopolymer is resistant to water, strong acid and high and low temperature. And sodium methylsilicate (CH) added₅SiO₃Na) capable of forming a protective film (CH) on the surface of the geopolymer₃-) to further improve the chemical resistance of the polymer.

5. Has the cost performance of development potential. If the aluminum-silicon oxide material is imported from abroad, the manufacturing cost of the 40cm geopolymer aquifer is about 550-650 Yuan/m³Meanwhile, if a domestic aluminum-silicon oxide material is selected (a novel production process is involved, the domestic production is rare at present (at present, no factory professional production is carried out at domestic, but the technical bottleneck is not realized, but the commercial value of the high-activity aluminum-silicon oxide is not realized), the manufacturing cost can be reduced to about 1/4-1/3 of the domestic aluminum-silicon oxide material, namely about 140-200 yuan/m³In the meantime.

6. Can be recycled. The geopolymer can be decomposed and recombined under the strong alkaline environment (PH is more than 14), and the characteristic is favorable for recycling the geopolymer waste.

Drawings

The invention is further described with reference to the accompanying drawings and the detailed description.

FIG. 1 is a block diagram of the present invention (load bearing geopolymer-based impounded water roadway);

in the figure, 1 is a permeable asphalt layer, 2 is a permeable concrete layer, 3 is a geopolymer water storage layer, 4 is valves, 5 is a cement concrete lower seal layer, and 6 is a cement concrete edge seal layer.

Detailed Description

Referring to fig. 1, the structure of a load-bearing geopolymer-based water-retaining road comprises a permeable asphalt layer, a permeable concrete layer, a geopolymer water-retaining layer and a cement concrete lower sealing layer from top to bottom; there is cement concrete limit seal at road structure limit portion, and there is the drainage valve cement concrete limit seal bottom.

The asphalt layer permeates water, the concrete layer permeates water, cement concrete lower sealing coat, cement concrete limit sealing coat, and drainage valve all has the mature technique, no longer gives unnecessary details.

The construction process of the geopolymer aquifer is as follows (taking metakaolin as an example):

1. prepare the material and calculate the amount. Metakaolin (53% Si 0) is selected₂，43.8％Al₂O₃) As an aluminum silicon oxide; selecting a mixed solution of analytically pure (the purity is more than or equal to 96 percent) NaOH particles, 2.3-modulus liquid sodium silicate and water as an alkali activator; sodium methyl silicate is selected as a tackifier (or not); selecting crushed stone of about 10mm as aggregate; and the amount is calculated according to aquifer size (approximately every 160 g)Metakaolin, 267g liquid sodium silicate, 7.6g sodium hydroxide particles, 33.5g water, 1760g coarse aggregate can be made into a geopolymer aquifer cube of 10cm x 10 cm).

2. Preparing an alkali activator. According to the above Table 1 (summary of the invention), the Si/Al molar ratio is 2, the Al/Na molar ratio is 1, H₂O/Na₂The molar ratio of O is selected to be 15, and the configuration amount of each material of the alkali-activator is calculated (metakaolin provided: Si, Al; water glass provided: Na, Si, H)₂O; NaOH pellets provided: na, H₂O (water of hydration)), and left to stand for 4 hours after the preparation.

3. And (5) preparing the gel material. Metakaolin and an alkali activator are mixed. The gel material needs to be kept stand for 1-15 hours in a shade place (has special rheological property after aging). This example was aged for 1 hour.

4. Adding a performance optimizing agent. In this example, sodium methyl silicate, which is 1.7 to 6.8% by mass of the geopolymer gel, was added as an additive, and the mixture was allowed to stand for 20 minutes after mixing.

5. Aggregate was added and stirred. In this example, coarse aggregate having a particle size of about 10mm and a total weight ratio of 77.3% was added, and the mixture was stirred in the same manner as the water-stable crushed stone.

6. And (6) paving. The paving mode is the same as the water-stable macadam paving mode.

7. And (5) maintaining. After 4 hours of film covering and curing, the film is removed and naturally dried for 3-15 days (the specific drying time depends on the activity of the selected silicon-aluminum oxide, and the drying time is 7 days in the embodiment), and the whole process does not need watering and curing.

Claims

1. But bearing geopolymer basic unit retaining road, its characterized in that: the top-down's structure is the asphalt layer that permeates water, the concrete layer that permeates water, geopolymer water-storage layer, and cement concrete lower sealing has cement concrete limit sealing at road structure limit portion, and cement concrete limit sealing bottom sets up drainage valve.

2. A geopolymer aquifer according to claim 1, wherein: the gel material is geopolymer gel, and the aggregate is open-graded coarse aggregate.

3. The geopolymer gel of claim 2, characterized in that: the selected silicon-aluminum oxide is metakaolin, fly ash or treated waste concrete powder.

4. The geopolymer gel of claim 2 or 3, characterized in that: geopolymer gel formulations depend on gel aggregate adhesion and final strength (mixture of aggregate and gel); the molar ratio range of elements and compounds in the gel is as follows: 1.8 to 2.5 of Si/Al, 0.8 to 1.2 of Al/Na, and H₂O/Na₂O＝13.5～17.0。

5. Geopolymer gel according to claim 2, 3 or 4, characterized in that: the gel needs to be aged for 1-15 hours after the preparation.

6. The geopolymer gel of claim 2, 3, 4 or 5, characterized in that: aging and adding sodium methyl silicate (CH)₅SiO₃Na) is used as a performance optimizing agent, and the addition amount of the Na) is 1.7 to 6.8 percent of the mass of the gel.

7. A geopolymer aquifer according to claim 1 or 2, characterized in that: after the paving, film covering and curing are needed for 4-20 hours, and then film removing and drying are carried out for 3-15 days.