Rainfall intensity effects on pavement base lay in Basrah

Other Title(s)

تأثير الشدة المطرية على طبقات التبليط في مدينة البصرة

Dissertant

al-Hilfi, Wisam Abd Allah Najm

Thesis advisor

al-Kazimi, Ahmad Majid Hamad
Ahmad, Lamya Abd al-Jalil

Comitee Members

Abbas, Abd al-Husayn A.
al-Wash, Ali A. A.
Muhammad, Umran Isa

University

University of Basrah

Faculty

Engineering College

Department

Department of Civil Engineering

University Country

Iraq

Degree

Master

Degree Date

2013

English Abstract

In this thesis a study of the effect of rainfall intensity on pavements layers thickness is presented and for two types of pavement : flexible and rigid pavements and also, calculation time - to - drain and drainage coefficient for base and sub - base layers.

It is the best known parameter for determining drainage performance of a permeable base( base and sub - base ).

This is using (Maple 13)software for modeling of this problem and calculation the rainfall intensity and pavement infiltration ; for purpose calculation drainage coefficient for base ,sub - base and sub - grade and its true effect on drainage and pavement design.

Where, soil types have been used in this study Well-graded sand ,Uniform dense sand and Fine-grain soil.

It was found that pavement infiltration increases with increasing rainfall intensity because of , increase in rainfall intensity caused an increase in the infiltrated water to the base and sub - base layers.

Accordingly an increase in pore water pressure resulted which in tends cause an increase in porosity and decrease of base and sub - base degree of compaction.

Accordingly which leads to increase in time - to- drain , decrease in drainage coefficient for base and sub - base, and subsequently, request to increase their thickness.

For flexible pavement , rainfall intensity 256 mm/hr is giving pavement infiltration, thickness and drainage coefficient 3.2m/day, 46 cm, 0.57 respectively and rainfall intensity 25 mm/hr is giving pavement infiltration, thickness and drainage coefficient 0.4 m/day, 18.5cm, 1.7 respectively.

In rigid pavement , rainfall intensity 256 mm/hr is giving thickness and drainage coefficient 24.8 cm, 0.9 respectively and rainfall intensity 25 mm/hr is giving thickness and drainage coefficient 21.3cm, 1.2 respectively.

drainage of accumulated water on pavement is accordingly drained rapid in as short time as possible due to minimize potential moisture damage to a pavement structure It was found that water in the pavement system can lead to modulus reduction and loss of strength for pavement.

Saturation can reduce the dry modulus of both the asphalt layer (30% or more) and the base and sub-base modulus (50% or more) .

Similarly, modulus reduction of up to 30 percent can be expected for asphalt-treated bases, and over 50 percent for saturated fine-grained sub grade soils .

It was found that soil types effects of moisture in pavement have been based on conditions of total saturation with loss of pavement strength from through affect the state of stress through suction(effective porosity) or pore water pressure and affect the structure of the soil through destruction of the cementation between soil particles because of, soil types difference in coefficient of permeability.

Where, soil types have been used in this study Well-graded sand ,Uniform dense sand and Fine-grain soil.

Main Subjects

Civil Engineering

No. of Pages

82

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-746504