Construction Materials and Soil Properties

Posted on May 3, 2024 in Geology

Permeability: The ability of liquids to pass through a material under pressure and temperature variations. Capillarity: The ability of a solid to attract and draw liquids upward, wetting its surface.

Classification of Construction Products Based on Fire Reaction

Construction products are classified based on their reaction to fire, considering factors such as:

  • Temperature increase (RE)
  • Loss of mass (Δm)
  • Flame length (tf)
  • Flame spread (FS)
  • Potential calorific value (GCV)
  • Fire spread index (FIGRA)
  • Total heat emission (THR600s)
  • Lateral flame spread (LFS)
  • Smoke production rate (SMOGRA)
  • Total smoke propagation (TSP600s)

Classes of Construction Materials Based on Fire Reaction

Materials are classified into seven classes based on their contribution to fire:

  • A1 and A2: No contribution to fire
  • B: Very low contribution to fire
  • C: Low contribution to fire
  • D: Small contribution to fire
  • E: Tax determined
  • F: Not determined

Classification of Construction Elements Based on Fire Resistance

Construction elements are classified based on their fire resistance properties, including:

  • Bearing capacity (R)
  • Integrity (E)
  • Isolation (I)
  • Radiation (W)
  • Mechanical action (M)
  • Closing (C)
  • Smoke passage sealing (S)
  • Soot combustion resistance (G)
  • Fire protection capacity (K)

Examples of Construction Element Classifications

  • EI 30: Integrity and insulation for a minimum of 30 minutes
  • REI 60-M: Bearing capacity, integrity, and insulation for a minimum of 60 minutes, with mechanical action
  • EW 120-C: Radiation integrity for a minimum of 120 minutes, with closing

Mechanical Properties of Materials

Mechanical properties define how materials behave under external forces. Key properties include:

  • Resistance to breakage: The ability to withstand stress and deformation without breaking. This includes compression, tension, cutting, and bending.
  • Elasticity: The ability to deform under load and return to the original shape when the load is removed (obeying Hooke’s law).
  • Plasticity: The ability to deform permanently without cracking.
  • Fragility: The inability to undergo plastic deformation and breaking easily beyond the elastic limit.
  • Acrimony: The increase in hardness and tensile strength due to deformation.
  • Hardness: The resistance to surface deformation by scratching, penetration, elastic impact, and shear.

Electrochemical Cells

Electrochemical cells involve the transfer of electrons between electrodes, generating electricity. For current to flow, specific conditions are necessary:

  • Electron transfer reactions at each electrode
  • Connection of electrodes through a conductor
  • Connection of cells through a salt bridge

Spanish Legislation

Relevant Spanish legislation for construction includes:

  • CTE (Technical Building Code)
  • DITE (European Technical Approval)
  • NBE (Basic Building Rule)
  • NTE (Technological Standard of the Edition)

Formulas

Various formulas are used to calculate properties of materials, such as density, compactness, and saturation modulus.

Chemical Environment: Air

Air is a mixture of gases surrounding the Earth, primarily composed of nitrogen, oxygen, and trace amounts of other gases. The atmosphere is divided into layers:

  • Troposphere: The lowest layer, containing most weather phenomena.
  • Stratosphere: Contains the ozone layer, which absorbs UV radiation.
  • Mesosphere: Where meteors burn up.
  • Ionosphere: Contains ionized gases that reflect radio waves.
  • Exosphere: The outermost layer, gradually transitioning to space.

Environmental Issues

Environmental concerns related to construction materials and soil include:

  • Greenhouse effect: Warming of the Earth due to greenhouse gases trapping heat.
  • Acid rain: Rainfall with a low pH due to pollutants.
  • Photochemical smog: Air pollution caused by reactions between sunlight and pollutants.
  • Pollution and climate change: Rising temperatures and changing weather patterns due to human activities.

Durability of Materials

The durability of materials depends on the environment they are exposed to. Different environments pose various challenges:

  • Interior: Controlled temperature and humidity, but potential for chemical exposure.
  • Rural: Low pollution, but high solar radiation.
  • Mountain: Strong winds, ozone, and frost.
  • Urban: Moderate pollution levels.
  • Industrial: High levels of chemical pollutants.
  • Marine: High humidity, salt exposure, and strong winds.
  • Tropical: High radiation, humidity, and temperature, promoting biological attacks.
  • Buried: Constant humidity and potential for chemical reactions.

EHE (Concrete Structure Instruction)

The EHE identifies different types of environments and their aggressiveness towards concrete structures. Factors such as corrosion, frost, chemical attack, and erosion are considered.

Biological Actions

Living organisms can degrade materials through various mechanisms, including putrefaction, consumption, and physical damage.

Chemical Actions

Chemical reactions with pollutants can cause degradation of materials, including acid rain and chemical products used in construction.

Physical Actions

Physical forces such as wind, seismic activity, and temperature fluctuations can cause deformation, movement, vibration, and breakage of materials.

Soil

Soil is the outer layer of the Earth’s crust, formed by the weathering of rocks. It is composed of particles of various sizes and minerals, with significant pore space.

Origin of Soil

Soil formation involves physical and chemical weathering processes, including:

  • Physical weathering: Breaking down of rocks by temperature changes, water, and wind.
  • Chemical weathering: Decomposition of rocks by chemical reactions.
  • Biological weathering: Breakdown of rocks by living organisms.

Types of Soil

Soils are classified based on particle size, including:

  • Gravel: Largest particles, with good drainage.
  • Sand: Visible particles, with moderate drainage.
  • Silt: Fine particles, retaining water better than sand.
  • Clay: Very fine particles, with high water retention and plasticity.

Soil Classification

The EHE classifies soils based on their geotechnical properties and potential risks, ranging from T-1 (favorable) to T-3 (adverse).

Expansive Soils

Expansive soils contain minerals that absorb and lose water, causing volume changes. This can lead to damage to structures. The potential for expansion is evaluated using laboratory tests, such as the LAMB test.