Types of Road Pavement

·  Flexible Pavement (Bituminous Pavements) :


Flexible pavements are constructed of several layers of natural granular material
covered with one or more waterproof bituminous surface layers, and as the name imply, is
considered to be flexible. A flexible pavement will flex (bend) under the load of a tyre. The
objective with the design of a flexible pavement is to avoid the excessive flexing of any layer,
failure to achieve this will result in the over stressing of a layer, which ultimately will cause the
pavement to fail. In flexible pavements, the load distribution pattern changes from one layer
to another, because the strength of each layer is different. The strongest material (least
flexible) is in the top layer and the weakest material (most flexible) is in the lowest layer. The
reason for this is that at the surface the wheel load is applied to a small area, the result is high
stress levels,deeper down in the pavement, the wheel load is applied to larger area, the result
is lower stress levels thus enabling the use of weaker materials.  

·   Rigid Pavement (Concrete pavement):
Rigid pavements are composed of a PCC surface course. Such pavements are
substantially "stiffer" than flexible pavements due to the high modulus of elasticity of the PCC
material. Further, these pavements can have reinforcing steel, which is generally used to
reduce or eliminate joints. The increased rigidity of concrete allows the concrete surface layer
to bridge small weak areas in the supporting laye through what is known as beam action. This
allows the placement of rigid pavements on relatively weak supporting layers, as long as the
supporting layer material particles will not be carried away by water forced up by the pumping
action of wheel loads.




Comments

Post a Comment

Popular posts from this blog

(3) Disintegration:

The progressive   breaking   up   of the   pavement   into   small, loose   pieces   is   called disintegration. If the is integration is not repaired in its early stages, complete reconstruction of the pavement may be needed. The two most common types of disintegration are: 1. Potholes 2. Patches Potholes: Potholes are bowl-shaped holes similar to depressions. They are a progressive failure. First, small fragments of the top layer are dislodged. Over time, the distress will progress downward into the lower layers of the pavement. Potholes are often located in areas of poor drainage, as seen in Figure. Potholes are formed when the pavement disintegrates under traffic loading, due to inadequate strength in one or more layers of the pavement, usually accompanied by the presence of water. Most potholes would not occur if the root cause was repaired before development of the pothole. Repair by excavating an...
Read more

FAILURE OF ROAD PAVEMENT

INTRODUCTION                       " ROAD   PAVEMENT "      “That with which anything is paved; a floor or  covering of solid material, laid so as to make   a hard  and convenient surface for travel; a paved road or sidewalk; a decorative interior floor of tiles collared bricks”                    1.1    General : -  A number of portions of the National Highways by NHAI (National Highway Authority of India) and Rural roads under PMGSY ( Pradhan Mantri Gram Sadak Yojna - A special scheme to connect the rural areas of India to all weather roads by Ministry of Rural Development) around the country are being strengthened and simultaneously being widened. But with the passage of time, the traffic intensity increased on these roads and the pavements started showi...
Read more

CHAPTER: 2 STUDY AREA POFILE

2.1   Site Introduction : Two sites of our project : o Khodiyar Colony , Near   Crystal Mall, Jamnagar. o Ranjit Sagar Dam, Approach Road. 2.1.1 Khodiyar Colony , Near. Crystal Mall This site is   3 km away from Jamnagar near the “ Valsura Road”. The study area consideration comprises of one lane road and is having width of about 12m approach. The length of road is about 2km out of which about 0.5km of road length is badly damage. The road pavement is 50mm thick. This road is   used for heavy transportation. 2.1.1    Rangit Sager Dam Approach Road: Second site is near Rangit Sagar Dam 12 km away from Jamnagar city On Jamnagar Smana road (SH-229). The length of road is about 2 km and width is about 4.50m out of which about 1 km of road length this deadly damage. The road pavement is rigid maid of cement concrete about 150mm thickness.
Read more