17 - CIVE 2700 Civil Engineering Materials, Winter 2007...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
CIVE 2700 – Civil Engineering Materials, Winter 2007 1 Asphalt Concrete Professor George Hadjisophocleous, Ph.D., P.Eng. Carleton University Department of Civil and Environmental Engineering Ottawa, Ontario CIVE 2700 – Civil Engineering materials, Winter 2007, 16.2 Introduction • Asphalt concrete is a mixture of asphalt cement and mineral aggregates. • It is used primarily as the surface layer in flexible pavement structures. • The following layers are typically found: – Asphalt concrete surface – Granular base – Granular sub-base – Prepared sub-grade
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
CIVE 2700 – Civil Engineering Materials, Winter 2007 2 CIVE 2700 – Civil Engineering materials, Winter 2007, 16.3 Introduction • Asphalt cement is a viscous cementitious material composed primarily of high molecular weight hydrocarbons. • Asphalt concrete is a mixture of asphalt cement and mineral aggregates. CIVE 2700 – Civil Engineering materials, Winter 2007, 16.4 Introduction Above 140 ! C, asphalt cements behave like Newtonian fluids, below 140 ! C they behave as visco-elastic solids. At very low temperatures they behave as a brittle elastic solid. Because viscosity is high even at high temperature, the asphalt concrete mix does not have the flow properties needed for casting. Static or vibratory compaction is used. Bitumen is a solid, semisolid or viscous cementitious material. It is composed of various mixtures of complex hydrocarbons. All bituminous materials are completely soluble in carbon disulfide (CS 2 ) and are nonvolatile, nontoxic and soften when heated.
Background image of page 2
CIVE 2700 – Civil Engineering Materials, Winter 2007 3 CIVE 2700 – Civil Engineering materials, Winter 2007, 16.5 Introduction Most common bituminous materials are asphalts, tars and pitches. Asphalts are available in natural deposits or are produced from petroleum processing. Tars and pitches are the products of distillation of materials such as wood, coal and shale. Useful properties of bitumens: Ability to adhere to solid particles such an aggregate and brick; water resistance, impermeability. They are ideal for use in pavements as an impervious layer, in roofs, shingles or built-up roofing. CIVE 2700 – Civil Engineering materials, Winter 2007, 16.6 Bituminous Materials Bitumen’s • Cutback asphalt – Tars -- Slow curing – Pitches -- Medium curing – Asphalts -- Rapid curing Asphalts Natural deposits: native asphalts, rock asphalts Petroleum asphalts Petroleum asphalts Asphalt cement (solid and semi-solid) Emulsified asphalts Blown asphalt (semisolid) Cutback asphalt (liquid)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
CIVE 2700 – Civil Engineering Materials, Winter 2007 4 CIVE 2700 – Civil Engineering materials, Winter 2007, 16.7 Bituminous Materials CIVE 2700 – Civil Engineering materials, Winter 2007, 16.8 Tars and Pitches
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/13/2011 for the course CIVE 2*** taught by Professor - during the Spring '11 term at Carleton CA.

Page1 / 22

17 - CIVE 2700 Civil Engineering Materials, Winter 2007...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online