Civil Materials Engineering Overview

A thin layer of material containing microencapsulated paraffin is used for temperature equalization.

When the room temperature exceeds 24°C, the paraffin melts and absorbs heat, then solidifies at lower temperatures, releasing stored heat.

The Teflon-coated fiberglass membrane roof used for the Riyadh International Stadium.

<p>The future needs include recyclable or biodegradable materials and the use of new biodegradable natural plastics.</p> Signup and view all the answers

<p>They provide a low life-cycle cost alongside desirable engineering properties.</p> Signup and view all the answers

<p>The climatic background is a key factor influencing material choice.</p> Signup and view all the answers

<p>It significantly contributes to the economy as its output affects both the rate and quality of construction work.</p> Signup and view all the answers

<p>Designers demand high strength with low weight in structural materials.</p> Signup and view all the answers

<p>The key factors include initial and life-cycle maintenance cost, mechanical properties, durability, ease of construction, and aesthetics.</p> Signup and view all the answers

<p>Environmental factors such as usage and climate/weather can influence the mechanical properties and durability of construction materials.</p> Signup and view all the answers

<p>It investigates the properties of construction materials, including raw ingredients and mixed products, to ascertain their suitability.</p> Signup and view all the answers

<p>Forensic engineering studies the failure of civil engineering systems, while materials engineering seeks to understand the structure and behavior of materials.</p> Signup and view all the answers

<p>Geosynthetics such as geotextiles, geomembranes, and geogrids are expected to have significant impacts.</p> Signup and view all the answers

<p>The field is witnessing increased integration of nanoscience and intelligent materials, leading to innovative civil structures.</p> Signup and view all the answers

<p>The atomic structure of a material governs its properties and performance in specific applications.</p> Signup and view all the answers

<p>The ultimate goal is to expand the uses of existing materials and develop new materials with desired specific properties.</p> Signup and view all the answers

<p>The formula for calculating density is $p = \frac{M}{V}$, where M is mass in grams, and V is volume in cubic centimeters.</p> Signup and view all the answers

<p>Bulk density is generally expressed in kg/m³ to avoid inconveniences, as it accounts for the natural state of the material including pores and voids.</p> Signup and view all the answers

<p>The Density Index ($ρ_i = \frac{ρ_b}{ρ}$) indicates the degree to which a material's volume is filled with solid matter.</p> Signup and view all the answers

<p>Building materials must possess strength at varying temperatures, resistance to different water conditions, and durability for interior decoration.</p> Signup and view all the answers

<p>Density refers to the mass of a unit volume of homogeneous material, whereas bulk density considers the mass of a unit volume in its natural state, including pores and voids.</p> Signup and view all the answers

<p>A comprehensive knowledge of material properties allows for a rational choice of materials tailored to specific service conditions.</p> Signup and view all the answers

<p>Properties like strength and heat conductivity are significantly affected by bulk density, impacting overall material performance.</p> Signup and view all the answers

<p>Mineral binding materials can be subdivided into air-setting and hydraulic-setting varieties.</p> Signup and view all the answers

<p>Ductile materials can be drawn out without necking and exhibit plasticity, while brittle materials fail suddenly with little to no plasticity.</p> Signup and view all the answers

<p>Stiff materials have a high modulus of elasticity, causing them to deform less under load, while flexible materials have a low modulus, allowing significant bending without breakdown.</p> Signup and view all the answers

<p>Toughness refers to a material's ability to withstand heavy shocks and depends on its strength and flexibility.</p> Signup and view all the answers

<p>Copper is the most malleable material, and malleability refers to the ability of a material to be hammered into sheets without rupturing.</p> Signup and view all the answers

<p>Hard materials are characterized by their resistance to scratching and denting, with examples including cast iron and chrome steel.</p> Signup and view all the answers

<p>The formula is $γ = ρ ⋅ g$, where $ρ$ is the density of the material (kg/m³) and $g$ is gravity (m/s²).</p> Signup and view all the answers

<p>Specific gravity (G) is defined as $G = \frac {γ_s}{γ_w} = \frac {ρ_s}{ρ_w}$, representing the ratio of the weight/mass of a solid's volume to an equal volume of water at 4°C.</p> Signup and view all the answers

<p>Porosity (n) is the ratio of the volume of pores to the total volume of the material, calculated as $n = \frac {V_v}{V}$.</p> Signup and view all the answers

<p>The void ratio (e) is the ratio of the volume of voids ($V_v$) to the volume of solids ($V_s$) and is calculated as $e = \frac {V_v}{V_s}$.</p> Signup and view all the answers

<p>Hygroscopicity refers to a material's ability to absorb water vapor from the air, influenced by air temperature, relative humidity, and the size and number of pores.</p> Signup and view all the answers

<p>Water absorption (W_w) is calculated as $W_w = \frac {M₁-M}{M} \times 100$ or $W_w = \frac {M₁-M}{V} \times 100$, indicating the material's ability to retain water.</p> Signup and view all the answers

<p>Chemical resistance is a material's ability to withstand the action of acids, alkalis, and other corrosive substances; natural stone is an example of a material with high chemical resistance.</p> Signup and view all the answers

<p>The relationship is given by the formula $n = \frac {e}{1+e}$, linking the two measurements of material structure.</p> Signup and view all the answers

<p>Durability is the ability of a material to resist the combined effects of atmospheric and other factors.</p> Signup and view all the answers

<p>Weathering resistance is the ability of a material to endure alternate wet and dry conditions without considerable deformation and loss of mechanical strength.</p> Signup and view all the answers

<p>Water permeability refers to the capacity of a material to allow water to penetrate under pressure.</p> Signup and view all the answers

<p>Frost resistance denotes the ability of a water-saturated material to endure repeated freezing and thawing without significant loss of mechanical strength.</p> Signup and view all the answers

<p>Materials with large size pores have high heat conductivity because air inside the pores enhances heat transfer.</p> Signup and view all the answers

<p>Thermal capacity is the property of a material to absorb heat, described by its specific heat, and is important for assessing thermal stability in structures.</p> Signup and view all the answers

<p>Fire resistance is the ability of a material to withstand high temperatures without significant deformation or loss of strength.</p> Signup and view all the answers

<p>Some materials like clay bricks neither crack nor lose shape, whereas others like steel may suffer considerable deformation under high temperatures.</p> Signup and view all the answers