Portland and Hydraulic Cement Basics

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Questions and Answers

Which admixture is specifically used to protect underwater concrete from being washed out?

Alkali-Aggregate Expansion Inhibitors

Air-Detraining Admixtures

Anti-Washout Admixtures (correct)

Thickness Determining Admixtures

What type of steel is characterized by its resistance to corrosion and is commonly used in medical instruments?

Tool Steel

Carbon Steel

Alloy Steel

Stainless Steel (correct)

Which of the following is the primary purpose of determining pavement thickness?

To optimize decorative designs in construction

To measure the aesthetics of the surface

To assess the color of asphalt

To ensure compliance with government standards (correct)

What is a characteristic property of metals that indicates their ability to be shaped or bent without breaking?

Ductility Signup and view all the answers

Which type of steel is typically utilized in auto parts due to its composition of other metals?

Alloy Steel Signup and view all the answers

What test is used to verify if pavement meets construction standards?

Core Boring Test Signup and view all the answers

Which structural steel shape is commonly found in beams and columns?

W-shape Signup and view all the answers

What property of metals describes their appearance when cut or polished?

Luster Signup and view all the answers

What type of stress compresses or shortens the material?

Compressive Stress Signup and view all the answers

What is the primary use of zinc in industrial applications?

For galvanizing steel to prevent corrosion Signup and view all the answers

Which type of stress tends to shear the material?

Shearing Stress Signup and view all the answers

What does strain refer to in the context of materials?

The deformation of a solid due to stress Signup and view all the answers

Which device measures the deformation of a specimen during testing?

Extensometer Signup and view all the answers

In materials testing, what is the purpose of a universal (hydraulic) testing machine?

To apply tensile loads at a controlled rate Signup and view all the answers

What is bending strength (flexural strength) primarily a measure of?

Ability to resist deformation under load Signup and view all the answers

Which term describes the elongation or contraction of a line segment due to stress?

Normal Strain Signup and view all the answers

What is the primary reason for using steel reinforcement in plain concrete?

To provide necessary tensile strength Signup and view all the answers

Which type of rebar is most economical for construction projects?

Unfinished steel rebar Signup and view all the answers

What is the approximate tensile strength range of prestressing steel bars?

250,000 – 270,000 psi Signup and view all the answers

Why are twists and grooves added to the surfaces of rebar?

To improve bonding with concrete Signup and view all the answers

What precaution is taken to ensure worker safety during rebar installation?

Capping rebar ends with plastic Signup and view all the answers

In conditions where rebar may be exposed to harsh environments, which option is preferred?

Epoxy-coated or stainless steel rebars Signup and view all the answers

What is one of the primary advantages of steel reinforcement regarding its interaction with concrete?

It prevents floating during pouring. Signup and view all the answers

How is rebar typically delivered to construction sites?

Directly from the manufacturer Signup and view all the answers

What is the primary purpose of reinforcing steel bars in concrete structures?

To provide strength in tension and flexibility Signup and view all the answers

Which letter denotes carbon-steel as per the bar markings system?

S Signup and view all the answers

What is one disadvantage of steel reinforcement mentioned?

It is prone to corrosion Signup and view all the answers

Which test measures the rebar's ability to withstand tension?

Tensile Test Signup and view all the answers

What specialized equipment is used to bend rebar on construction sites?

Hydraulic benders and cutters Signup and view all the answers

Which symbol represents low-alloy steel in reinforcing bars?

W Signup and view all the answers

What does the bar size marking indicate?

The diameter and length of the bar Signup and view all the answers

What is the common method for connecting ends of rebar that cannot be welded?

Wire and coupling splices Signup and view all the answers

What does grade marking on a rebar indicate?

The grade or classification of the rebar Signup and view all the answers

Which grade of rebar is represented by two lines on the bar?

Grade 75 Signup and view all the answers

What is the main purpose of fatigue testing for rebar?

To evaluate the rebar's endurance under repeated stress Signup and view all the answers

Which machine is essential for conducting tensile tests on rebar?

Universal (Hydraulic) Testing Machine Signup and view all the answers

During the testing procedure, what is the purpose of the preload step?

To seat the specimen properly in the machine Signup and view all the answers

What is typically observed when the material transitions from the elastic to plastic deformation?

A defined yield point is reached Signup and view all the answers

What characteristic must the testing equipment have for accommodating specimens?

It must handle specimens with slight bends Signup and view all the answers

What role does rebar serve in concrete structures?

Acts as a primary and secondary support system Signup and view all the answers

What does the viscosity test help to understand about bitumen?

The resistance of bitumen to flow Signup and view all the answers

What is the flash point of bitumen?

The temperature at which vapors momentarily ignite Signup and view all the answers

What method is preferred globally for the bitumen extraction test?

Centrifuge method Signup and view all the answers

What might a high viscosity indicate during mixing and compaction of bitumen?

Potential difficulties in processing Signup and view all the answers

At what temperature is the float test conducted to measure the consistency of bitumen?

50°C Signup and view all the answers

Why is the bitumen extraction test conducted?

To determine the actual amount of bitumen in a sample Signup and view all the answers

What is the typical specific gravity range for bitumen?

0.97 to 1.02 Signup and view all the answers

What is a potential risk associated with the storage and application of bitumen?

Ignition at low temperatures due to vapor accumulation Signup and view all the answers

Study Notes

Portland and Hydraulic Cement Concrete

Hydraulic Cement: Sets quickly after mixing with water, used to seal structures against water leakage.
- Uses: swimming pools, drainage systems, foundations, basement walls, manholes, marine applications, chimneys, cisterns, and fountains.
Portland Cement: Made by finely grinding clinker (from calcined materials), a hydraulic cement that hardens under water.
- Composition: Calcium silicates with some gypsum.
Types of Portland Cement:
- Type I: General-purpose cement.
- Type IA: Air-entrained Type I.
- Type II: Moderate sulfate resistance.
- Type IIA: Air-entrained Type II.
- Type III: High early strength.
- Type IIIA: Air-entrained Type III.
- Type IV: Low heat of hydration.
- Type V: High sulfate resistance.
Admixtures in Concrete: Chemicals added to enhance properties.
- Types: Accelerating, air-entraining, water-reducing, retarding, damp-proofing, gas-forming, alkali-aggregate expansion inhibitors, and anti-washout.

Completed Pavement

Importance of Concrete Slab Thickness: Significantly impacts pavement performance and lifespan.
- A 1-inch reduction in thickness can reduce service life by up to 50%.
Techniques for Thickness Determination:
- Core Boring: Uses ASTM C 174 standard for drilling and extracting cores (101.6 mm or 152.4 mm diameter). Suitable for asphalt pavement up to 250mm thick.
- Impact-Echo Method: Non-destructive testing (ASTM C 1383), measures thickness, detects internal cracks and air voids without surface damage (applicable for concrete pavements and walls).
- Magnetic Imaging Tomography (MIT-SCAN-T2): Handheld device measuring pavement thickness using electromagnetic pulses (up to 508 mm or 20 in.).
Standard Pavement Thickness (Philippines):
- Portland Cement Concrete Pavement (PCCP): Minimum 280mm for new constructions, 260mm for rehabilitation.
- Asphalt Pavement: Minimum 50mm for overlay works.
Significance of Pavement Thickness Determination: Ensures compliance with proposed thickness in construction plans.

Metals and Woods

Metals: Properties include hardness, shininess, malleability, fusibility, ductility, and conductivity.
Common Structural Steel Shapes: W-shape, S-shape, C-shape, steel angle, structural Tees, steel pipe and tubing.
Nonferrous Metal Properties:
- Aluminum: Lightweight, malleable, and corrosion-resistant.
- Copper: Excellent conductivity, corrosion-resistant.
- Lead: Heavy, soft, and corrosion-resistant.
- Zinc: Used in galvanizing steel, die-casting, etc.
Stress: Force per unit area.
- Types: tensile, compressive, shearing.
Strain: Deformation due to stress.
- Types: normal, shear.

Standard Test Methods for Tension Testing of Metallic Materials

Standard: ASTM E8/E8M
Procedure: Metal specimen gradually loaded in a tension-compression machine. Measures total elongation and calculates normal and strain.

Reinforcing Steel (Rebar)

Overview: Used in various concrete structures to enhance strength. Concrete is strong in compression but weak in tension; rebar compensates for this weakness.
Types: Hot Rolled Deformed Bars, Cold Worked Steel Bars, Mild Steel Plain Bars, Prestressing Steel Bars.
- Typical yield strengths: Hot Rolled Deformed Bars (60,000 psi), Prestressing Steel Bars (250,000-270,000 psi).
Needs: Plain concrete lacks tensile strength; steel reinforcement provides tensile properties. Similar coefficients of thermal expansion minimize stress during temperature changes. Proper bonding is achieved through patterned surfaces.
Advantages: Compatibility with concrete, robustness, bent properties, recyclability, and availability.
Disadvantages: Reactivity (corrosion) if moisture and salt penetrate the concrete cover, weakening the structure. Cost.

Bituminous Materials

Overview of Bituminous Materials/Asphalt: Used for roadway construction, binding characteristics, waterproofing, and cost-effectiveness.
Bitumen:** Amorphous, black substance derived for petroleum, a key component of asphalt.
Classification: Cutback, Bitumen Emulsion, Bituminous Primers, Modified Bitumen.
Kinds of Asphalt and Uses: Porous, Perpetual, Hot Mix, Warm-Mix, Quiet, and Thin Overlays.
Bituminous Waterproofing: Asphalt used in waterproofing products and flat roof sealants, preventing leaks and water damage.
Other Products: Coal tar pitch and other varieties, used in paints and roofing.

Bituminous Roof Covering

Roll Roofing: Consists of fiberglass mats or organic felt coated with bitumen. Available in various types.
Hot Bitumen Built-Up Roof Membrane: Involves layering felt with hot bitumen, creating waterproof membrane.
Modified Asphalt Roofing Systems: Comprising polymer-modified bitumen and fabrics for consistency across diverse applications.
Cold-Applied Asphalt Roofing System: Utilizes coated sheets and fabrics with cold-applied waterproofing agents.
Difference Between Asphalt and Bitumen: Bitumen is liquid and asphalt is a mixture (bitumen, aggregate, and sand).

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Description

Explore the fundamentals of Portland and hydraulic cement in this quiz. Learn about their composition, types, and various applications in construction. Test your knowledge on admixtures and their effects on concrete properties.