Table of Contents
What are the requirements of bituminous mixes?
Bituminous mixes should be stable, durable, flexible, workable and should offer sufficient skid resistance. The mix consists of coarse and fine aggregates, filler and binder. It may be well graded, open graded, gap graded or unbounded as per the requirements. As far as possible, it should be economical also.
What are the essential properties of bitumen mixes?
The main and essential features a bitumen mix must possess are explained below:
- Good Stability.
- Good Durability.
- Workability.
- Skid Resistance.
- Flexibility.
What are the different methods in determining the consistency characteristics of bituminous binders?
The following tests are usually conducted to evaluate different properties of bituminous materials.
- Penetration test.
- Ductility test.
- Softening point test.
- Specific gravity test.
- Viscosity test.
- Flash and Fire point test.
- Float test.
- Water content test.
Which procedure is used in designing and evaluating bituminous paving mixes?
The test procedure is used in designing and evaluating bituminous paving mixes, and is widely applied in routine test programs for the paving jobs. The major features of Marshall method of designing mixes are to determine the two important properties of strength and flexibility.
What is bituminous paving?
Bituminous paving mixtures are used as surface or base layers in a pavement structure to distribute stresses caused by loading and to protect the underlying unbound layers from the effects of water.
What is bituminous mixture?
Bituminous mixtures, sometimes called asphalt mixtures, are blends of aggregates with different gradations, filler type and content and hardness with bitumen of different grades and quantities.
What are the desirable properties of bitumen name one test for each?
1. Desirable Properties of Bitumen
- a. Adhesion: A good binder must bring all construction materials together and make it a single unit.
- b. Water Proof:
- c. Strength:
- d. Durability:
- e. Versatile:
- f. Economy:
- g. Hardness:
- h. Softening Point:
What are the problems associated with bituminous binders?
These are mainly permanent deformation, stiffness, low temperature cracking, fatigue cracking and adhesion.
What is bituminous concrete pavement?
BITUMINOUS CONCRETE means a mixture of petroleum by-products and gravel used for paving to form a smooth, permanent surface. It does not mean “oil and chip”.
What is bituminous mix?
What are the two major steps in Marshall bituminous mix design explain the important steps briefly?
The Marshall Mix Design method consists mainly of the following steps: (i) Determination of physical properties, size and gradation of aggregates. (ii) Selection of types of asphalt binder. (iii) Prepare initial samples, each with different asphalt binder content.
How is bitumen measured?
Bitumen Tests- Penetration Test It measures the hardness or softness of bitumen by measuring the depth in tenths of a millimeter to which a standard loaded needle will penetrate vertically in 5 seconds. BIS had standardised the equipment and test procedure.
What are properties of bituminous materials?
Properties of Bitumen and Bituminous Materials
- Adhesion.
- Resistance to Water.
- Hardness.
- Viscosity and Flow.
- Softening Point.
- Ductility.
- Specific Gravity.
- Durability.
What is the problem with bitumen?
In the long-term, bitumen exposure can cause lung and stomach cancer, pigment changes in the skin, bronchitis and emphysema. In addition, bitumen additives may cause damage to the liver, kidneys and nervous system. When hot bitumen releases hydrogen sulphide gas into the air, suffocation and even death may occur.
What are the properties of bituminous binder?
How are bituminous pavements maintained?
A bituminous surface treatment (BST), also known as a seal coat or chip seal, is a thin protective wearing surface that is applied to a pavement or base course. BSTs can provide all of the following: A waterproof layer to protect the underlying pavement.
How is optimum bitumen content determined in Marshall mix design?
The optimum bitumen content of bituminous mixtures is determined based on the average values that satisfy the sets of requirements for Marshall stability, Marshall flow, air voids, VMA and VFB. Figure 12.11 shows the optimum bitumen content for bituminous mixtures made with coarse, mixed-size and fine RCA.
What is Marshall method of bituminous mix design?
The Marshall Mix Design method was originally developed by Bruce Marshall of the Mississippi Highway Department in 1939. The main idea of the Marshall Mix Design method involves the selection of the asphalt binder content with a suitable density which satisfies minimum stability and range of flow values.
How do you determine the consistency of a bitumen sample?
Penetration test measures the hardness for consistency (softness) of bituminous material by measuring the depth in tenths of a millimeter to which a standard loaded needle will penetrate vertically into a sample of the material under standard conditions of temperature, in 5 seconds.
How do you prepare a bitumen sample?
Sample Preparation Take the bitumen sample in a vessel and heat it to a temperature of 75-100°C- above its approximate softening point. Allow the bitumen to melt until it is converted completely into a liquid state. Stir the bitumen if necessary so that it is melted completely and is free from air bubbles and water.