Rainfall Infiltration Influence to Asphalt Concrete Pavement - Advanced Research on Computer Education, Simulation and Modeling - page 172

(1) Infiltration rule transient flow analysis during the rainfall. In the initial rainfall
period, road surface volume water content will gradually increase, with the infiltration
of rainwater, the surface material's matrix suction achieves the water filling values, and
its volume water content will rapidly increase until the saturated state. The rainwater
does not infiltrate into the basic course, so the volume water content of the basic course
still maintains invariable.
(2) Drainage transient flow analysis after the rainfall. The road surface water supply
is zero after the rain stop. The situation of road surface enters into unsaturated drainage
stage from the saturated state. At this time, the road surface volume water content is
still increasing in a short time, but with the rain is expelled outside pavement structure
by graded crushed stone of base course, the surface course volume water content will
decrease rapidly. The permeability coefficient of the surface materials is very small,
and the infiltration time from surface course to basic course is too long, therefore, the
increase of basic course volume water content is very small after the rain stop.
4 Prevention and Control Measures
In recent years, the development of highway is very rapid, so we have put forward some
higher requirements to strength and stability of subgrade and pavement. But the
existing pavement drainage systems are often only concerned about the surface water
expel outside the road, think little of expelling the perched water of the pavement
structure. In the not setting effective pavement internal drainage system situation, the
perched water is very dangerous, it can make the mechanical properties of subgrade and
pavement change, affect the strength and stability of the road. It is one of the important
reasons which cause subgrade and pavement early destruction in a part of highway.
Therefore, rainfall infiltration in subgrade and pavement destruction of prevention and
control measures are having quite important significance.
(1) Consummating the pavement drainage system. We should handle both the
drainage system of road edge and the drainage system of drainage layer, add expel
seepage gravel layer in the shoulder, this is beneficial to reduce the residence time of
seepage.
(2) Coat a new-style waterproof material in pavement, the material will form a layer
of impermeable film on the pavement, so that the residence time of seepage is declined,
the road surface water is expelled outside as soon as possible, thus it can greatly reduce
the road damage.
(3) Between surface course and basic course set lower seal coat to enhance
the impermeability and surface water stability of basic surface.
(4) Improving the design and construction of surface course and basic course. In the
construction process, we should improve the standard of compaction machine, rolling
should be uniform, from light to heavy, from slow to fast, it is not only necessary to
ensure the smoothness of the pavement, but also ensure the compaction of the
pavement, thus, it can increase the adhesion of asphalt aggregate, and reduce the
damage of asphalt concrete pavement.