Plateau area pervious concrete mix proportion design method

Abstract

The invention discloses a plateau area pervious concrete mix proportion design method which comprises the following steps: step 1, testing the compressive strength and the permeability coefficient of existing pervious concrete, and selecting the existing pervious concrete meeting the requirements of a plateau area; 2, parameters of the coarse aggregate particle size, the water-binder ratio and the porosity of existing pervious concrete are obtained, and therefore function relations between the coarse aggregate particle size, the water-binder ratio and the target porosity and the compressive strength and the pervious coefficient are established; and step 3, obtaining the coarse aggregate particle size, the water-binder ratio and the porosity with the optimal compressive strength and the optimal permeable coefficient through the function relationship, and using the permeable concrete mix proportion of the coefficient for pavement paving in the plateau region. The influence of the aggregate particle size, the water-binder ratio, the porosity and the curing mode on the mechanical property and the permeability coefficient of the pervious concrete is considered, the relation between the mechanical property and the permeability coefficient is established, and the optimal mix proportion is obtained through the relation.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering materials, and in particular relates to a mix ratio design method for permeable concrete in plateau areas. Background Art

[0002] Permeable concrete is increasingly widely used in urban construction as an eco-friendly building material. Permeable concrete has good hydrological properties, can reduce flood runoff and form a natural drainage system. While alleviating urban waterlogging and improving groundwater quality, it can also effectively exchange heat in the air with water, alleviating the "heat island effect". Permeable concrete achieves permeability through its internal pores, but at the same time reduces structural strength. Its strength is generally lower than that of ordinary concrete and its durability is poor. Plateau and high-altitude areas, such as western China, have low ambient pressure, large temperature differences between day and night, often negative temperatures, and seasonal frozen soil. This harsh environment exacerbates the freeze-thaw degradation process and degree of permeable concrete, severely shortening the service life of permeable concrete. At the same time, due to the low ambient pressure, the bubbles in the concrete mixed with air-entraining agents are easy to rupture, resulting in unstable quality of permeable concrete and difficulty in meeting anti-freeze requirements.

[0003] The mechanical properties of permeable concrete are related to the properties of raw materials, porosity, and the bonding strength between aggregates and cementitious materials or pastes, and the permeability mainly depends on the porosity of concrete. Studies have shown that an appropriate sand ratio can increase the bonding surface area between aggregates, thereby improving the mechanical properties of permeable concrete. Adjusting the stacking state between aggregates and changing their stacking density also have an important impact on the mechanical properties and permeability of concrete. However, at present, permeable concrete is mainly designed based on the volume method. This is a mix design method that does not consider sand and mainly determines the amount of aggregate based on the stacking density of coarse aggregates. It cannot give full play to the sand ratio and the stacking effect between coarse aggregates. Summary of the invention

[0004] The purpose of the present invention is to provide a permeable concrete mix ratio design method for plateau areas. The design method considers the influence of aggregate particle size, water-cement ratio, porosity, and curing method on the mechanical properties and permeability coefficient of permeable concrete, establishes the relationship between the mechanical properties and the permeability coefficient, and obtains the optimal mix ratio through the relationship.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A method for designing a mix ratio of permeable concrete in plateau areas comprises the following steps:

[0007] Step 1: Test the compressive strength and permeability coefficient of existing permeable concrete, and select existing permeable concrete that meets the requirements of plateau areas;

[0008] Step 2: Obtain the parameters of coarse aggregate particle size, water-binder ratio and porosity of the existing permeable concrete, so as to establish the functional relationship between the coarse aggregate particle size, water-binder ratio and target porosity and the compressive strength and permeability coefficient respectively;

[0009] Step 3: Obtain the optimal coarse aggregate particle size, water-cement ratio and porosity for both compressive strength and permeability coefficient through functional relationship, and use the permeable concrete mix ratio with this coefficient for road paving in plateau areas.

[0010] Step 4: Simulate the environment of the plateau area and lay one cubic meter of permeable concrete with the permeable concrete mix ratio. Curing the concrete in water at 20℃, 30℃, 40℃, 50℃ and 60℃ for 3d, 7d and 28d, measure its compressive strength and permeability coefficient, establish the functional relationship between the compressive strength and permeability coefficient after curing at different water temperatures, and obtain the optimal curing method.

[0011] Furthermore, parameters of coarse aggregate particle size, water-cement ratio and porosity of at least 10 groups of permeable concrete as well as their compressive strength and water permeability coefficient are collected, and the functional relationships between the coarse aggregate particle size, water-cement ratio and target porosity and the compressive strength and water permeability coefficient are obtained by fitting curves.

[0012] The present invention determines the water permeability and compressive strength of existing concrete mix ratios, establishes two functional relationships, and obtains mix ratios with good permeability and compressive strength based on the functional relationships. On the basis of the existing ones, a mix ratio that meets the requirements and has higher performance is found as soon as possible, and then the optimal maintenance method is obtained by simulating the environment of plateau areas to maintain and pave the road surface, thereby extending the service life of the road surface in plateau areas. DETAILED DESCRIPTION

[0013] The present embodiment provides a method for designing a mix ratio of permeable concrete in plateau areas, comprising the following steps:

[0014] Step 1: Test the compressive strength and permeability coefficient of existing permeable concrete, and select existing permeable concrete that meets the requirements of plateau areas;

[0015] Step 2: Obtain the parameters of coarse aggregate particle size, water-binder ratio and porosity of the existing permeable concrete, so as to establish the functional relationship between the coarse aggregate particle size, water-binder ratio and target porosity and the compressive strength and permeability coefficient respectively;

[0016] Specifically, this embodiment collects parameters of coarse aggregate particle size, water-cement ratio and porosity of at least 10 groups of permeable concrete as well as its compressive strength and water permeability coefficient, and obtains the functional relationship between the coarse aggregate particle size, water-cement ratio and target porosity and the compressive strength and water permeability coefficient respectively through fitting curves.

[0017] Step 3: Obtain the optimal coarse aggregate particle size, water-cement ratio and porosity for both compressive strength and permeability coefficient through functional relationship, and use the permeable concrete mix ratio with this coefficient for road paving in plateau areas.

[0018] Step 4: Different curing methods change the temperature and humidity environment of concrete, which has an important impact on cement hydration and further affects the performance of concrete. Permeable concrete has pores inside, which increases the contact area with air and water, making it more sensitive to curing conditions.

[0019] The environment of plateau areas was simulated by paving one cubic meter of permeable concrete with a permeable concrete mix ratio. The concrete was cured in water at 20℃, 30℃, 40℃, 50℃ and 60℃ for 3d, 7d and 28d, and its compressive strength and permeability coefficient were measured. The functional relationship between the compressive strength and permeability coefficient after curing at different water temperatures was established to obtain the optimal curing method.

[0020] The above description is only a preferred implementation manner of the present invention, but the protection scope of the present invention is not limited thereto, and any modification and replacement based on the technical solution and inventive concept provided by the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing mix proportion of permeable concrete in plateau areas, characterized in that: The steps include: Step 1: Test the compressive strength and permeability coefficient of existing permeable concrete, and select existing permeable concrete that meets the requirements of plateau areas; Step 2: Obtain the parameters of coarse aggregate particle size, water-binder ratio and porosity of the existing permeable concrete, so as to establish the functional relationship between the coarse aggregate particle size, water-binder ratio and target porosity and the compressive strength and permeability coefficient respectively; Step 3: Obtain the optimal coarse aggregate particle size, water-cement ratio and porosity for both compressive strength and permeability coefficient through functional relationship, and use the permeable concrete mix ratio with this coefficient for road paving in plateau areas.

2. A method for designing mix ratio of permeable concrete in plateau areas according to claim 1, characterized in that: Also includes: Step 4: Simulate the environment of the plateau area and lay one cubic meter of permeable concrete with the permeable concrete mix ratio. Curing the concrete in water at 20℃, 30℃, 40℃, 50℃ and 60℃ for 3d, 7d and 28d, measure its compressive strength and permeability coefficient, establish the functional relationship between the compressive strength and permeability coefficient after curing at different water temperatures, and obtain the optimal curing method.

3. A method for designing mix proportion of permeable concrete in plateau areas according to claim 1 or 2, characterized in that: The parameters of coarse aggregate particle size, water-cement ratio and porosity of at least 10 groups of permeable concrete as well as their compressive strength and water permeability coefficient are collected, and the functional relationships between the coarse aggregate particle size, water-cement ratio and target porosity and the compressive strength and water permeability coefficient are obtained by fitting curves.