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Cement and Concrete Research
Volume 33, Issue 3, March 2003, Pages 381–386
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Experimental study on properties of pervious concrete pavement materials
Jing Yang, ,
Guoliang Jiang
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http://dx.doi.org/10.1016/S0008-8846(02)00966-3
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Abstract
In this paper, a pervious concrete pavement material used for roadway is introduced. Using the common material and method, the strength of the pervious concrete is low. Using smaller sized aggregate, silica fume (SF), and superplasticizer (SP) in the pervious concrete can enhance the strength of pervious concrete greatly. The pervious pavement materials that composed of a surface layer and a base layer were made. The compressive strength of the composite can reach 50 MPa and the flexural strength 6 MPa. The water penetration, abrasion resistance, and freezing and thawing durability of the materials are also very good. It can be applied to both the footpath and the vehicle road. It is an environment-friendly pavement material.
Keywords
Concrete;
Permeability;
Mechanical properties;
Durability
1. Introduction
Our cities are being covered with building and the air-proof concrete road more and more. In addition, the environment of city is far from natural. Because of the lack of water permeability and air permeability of the common concrete pavement, the rainwater is not filtered underground. Without constant supply of water to the soil, plants are difficult to grow normally. In addition, it is difficult for soil to exchange heat and moisture with air; therefore, the temperature and humidity of the Earth's surface in large cities cannot be adjusted. This brings the phenomenon of hot island in city. At the same time, the plash on the road during a rainy day reduces the safety of traffic of vehicle and foot passenger. The pervious concrete pavement possesses many advantages that improves city environment as follows:
1.
The rainwater can quickly filter into ground, so the groundwater resources can renew in time.
2.
As the pavement is air permeable and water permeable, the soil underneath can be kept wet. It improves the environment of road surface.
3.
The pervious concrete pavement can absorb the noise of vehicles, which creates quiet and comfortable environment. In rainy days, the pervious concrete pavement has no plash on the surface and does not glisten at night. This improves the comfort and safety of drivers.
4.
The pervious concrete pavement materials have holes that can cumulate heat. Such pavement can adjust the temperature and humidity of the Earth's surface and eliminates the phenomenon of hot island in cities.
The research on pervious pavement materials has begun in developed countries such as the US and Japan since 1980s. However, the strength of the material is relatively low because of its porosity. The compressive strength of the material can only reach about 20–30 MPa. Such materials cannot be used as pavement due to low strength. The pervious concrete can only be applied to squares, footpaths, parking lots, and paths in parks [1], [2] and [3]. Using selected aggregates, fine mineral admixtures, and organic intensifiers and by adjusting the concrete mix proportion, strength, and abrasion resistance can improve the pervious concrete greatly.
2. The pervious concrete model and measures for improving strength
A model of the pervious concrete is shown in Fig. 1. The pervious concrete is a porous composite material. The single-diameter aggregate forms the concrete framework. The cement paste or mortar binds the aggregate together. There are many pores with diameters above 1 mm in the pervious concrete, so water can penetrate through the concrete quickly, but the strength of the pervious concrete is relatively low due to the pores.
A schematic model of pervious concrete.
Fig. 1.
A schematic model of pervious concrete.
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Based on the model of the pervious concrete, when the concrete is subjected to loading, the load is transferred through the cement paste between aggregates. The strength of aggregate is high, whereas the strength of cement paste and the interface between the cement paste and the aggregate is relatively weak. In addition, the cement paste binder layer is very thin. Therefore, the pervious concrete always fails at the binder layer between the aggregates. Therefore, increasing the cement paste binder area and enhancing the strength of cement binder are the keys in improving the pervious concrete strength. In this study, two methods were used to improve the strength and other mechanical properties of the pervious concrete.
2.1. Increasing the cement paste binder area
Since the material must be permeable, the voids between aggregate particles cannot be entirely filled by cement paste. Using smaller size aggregate can increase the number of aggregate particles per unit volume of concrete. As the aggregate particles increase, the specifiวามวิจัย