Portland and Hydraulic Cement Basics

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).