Chapter 9 OTHER CONSTRUCTION MATERIAL

9.1. Bitumen 9.2. Rubber 9.3. Plastic 9.4. Polymer 9.5. Gypsum 9.6. Glass 9.7. Fiber Reinforced Polymer

The range of materials available to the engineer is vast and these materials may possess widely differing properties. Concrete, timber, steel, bitumen, glass, rubber and polymer are all used by engineers, but in character and properties they are completely different from one another. Every engineer is concerned with materials and has to select the most suitable material for the job in hand, be it for some civil engineering structure, or some power plant, or perhaps for an electronic component. An engineer has to consider many factors when making the selection because within one group of materials, properties may range from soft and easily deformed to tool steels which are hard and tough. 9.1 Bitumen

Butimen by definition is soluble in carbon disulfide. However, according to ASTM D8, butimen is a class of black or dark-colored (solid, semisolid, or viscous) cementitious substances, natural or manufactured, composed principally of high-molecular-weight hydrocarbons, of which asphalts, tars,

Figure 9.1: Natural Bitumen From Iran Mines

pithces and asphaltities are typical (Figure 9.1).

Most bitumens contain sulfur and several heavy metals such as nickel, vanadium, lead, chromium, mercury and also arsenic, selenium, and other toxic elements. Bitumens can provide good preservation of plants and animal fossils.

Properties of Bitumen

The Paving Grades of bitumen are 30/40, 60/70 and 80/100. The grade 80/100 is commonly used in Malaysia but for lower temperatures other grades are preferable.

Bitumen Application

Bitumen is primarily used for paving roads. Its other uses are for bituminous waterproofing products, including the use of bitumen in the production of roofing felt and for sealing flat roofs.

Thin bitumen plates are sometimes used by computer enthusiasts for silencing computer cases or noisy computer parts such as the hard drive. Bitumen layers are baked onto the outside of high end dishwashers to provide sound insulation.

Bitumen alternatives

Bitumen can now be made from non-petroleum based renewable resources such as sugar, molasses and rice, corn and potato starches. Bitumen can also be made from waste material by fractional distillation of used motor oils, which is sometimes disposed by burning or dumping into land fills. Non-petroleum based bitumen binders can be made light-colored. Roads made with lighter-colored pitch absorb less heat from solar radiation, and become less hot than darker surfaces, reducing their contribution to the urban heat island effect.

Methods of Testing Most present day standard were developed in the early 1900s. Equipment has change becoming electric and better control can be accomplished during the testing period of the product.

2. Sampling Bituminous (ASTM D140) - cover the method used to

sample bituminous material at points of manufacture, storage or delivery

- is to determine the true nature and condition of the material

1. Specific Gravity (ASTM D70) - use of a pycnometer - can be expressed as the ratio

of the weight of a given volume of the material at 250C or at 15.60C to that of an equal volume of water at the same temperature

Met

hod

of T

estin

g

5. Penetration of Bituminous Materials (ASTM D5) - measure the hardness and

softness of the material - test are taken at least 3

determination on the surface of the sample at points not less than 10 mm from the side of the container and not less than 10 mm apart.

- However, the test is empirical and many engineers would like to replace it with ASTM D2171 (Viscosity of Asphalts by Vacuum Capillary Viscometer)

3. Ductility (ASTM D113) - is measured by the distance

to which it will elongate before breaking when 2 ends of specimen are pulled apart at a specified speed and temperature

- to measure the adhesive and elasticity of the asphalt.

4. Viscosity - ASTM D2170 : Kinematic

Viscosity of asphalt (Bitumen) - Covers determination of the

kinematic viscosity of liquid asphalt (bitumen), road oils and distillation residue of liquid asphalt (bitumen), all at 600C and for asphalt cement at 1350C in the range of 6 to 100,000 centistokes.

- Meadure the resistance to flow of a liquid under gravity.

- ASTM D2171 : Viscosity of asphalt by Vacuum Capillary Viscometer

- Determination of viscosity of asphalt (bitumen) by vacuum capillary viscometer at 600C.

- It is applicable to material having viscosities in the range from 0.036 to over 200,000 poiss (P).

6. Float Test (ASTM D139) - is a consistency test used for

material that are too soft to undergo the standard penetration test and too hard for use with viscosity test

Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. Urban heat island is a metropolitan area which is significantly warmer than its surrounding rural areas.

Pithces is the name for any of a number of highly viscous liquids which appear solid. Pitch can be made from petroleum products or plants Molasses is a viscous by-product from the processing of the sugar beet or sugar cane into sugar

9.2 Rubber Christopher Columbus has been the first Europeans to handle natural rubber since it was reported that some tribes of South American Indians played ball games well before the days of Pele!. Rubber is a very important material used in a wide range variety of product. It is an elastomer. This is a substance in which the arrangement of the polymer molecules allows considerable reversible extension to take place at normal temperatures. Elastomer exists as long chain molecules which are irregularly coiled, bent and generally entangled when in the unstressed state. Engineering Properties of Elastomer Rubber Elastomer is used in Civil Engineering for some good reason such as:

- Long lasting - Good in impact absorption - Good bonding with metal - Good resistance to ageing - Good tearing properties - Good physical properties - Good resistance to oil and chemicals - Suitable for hot and cool temperature.

However, elastomer rubber is expensive especially for rubber with high resistance to ageing. It also can be attack by ester, ketone, hydrocarbon with nitrogen and aromatic. Table 9.1 shows physical properties of the elastomer. Engineering Application of Elastomer Rubber To be value in engineering, a rubber must have a low hysteresis, that is, it must return within very close limits to its original shape following each successive deformation cycle of loading and unloading. In civil engineering, elastomer rubbers are mostly used for bridge and building structure where cyclic loading such as vehicles and earthquake plays major role. Types of elastomer rubber used are:

(i) natural rubber (ii) Neoprene (iii) High Damping Rubber (HDRB) (iv) Styrene-butadiene Rubber (SBR) (v) Acrylonitrile-butadiene Rubber (NBR) or Nitrile Rubber (vi) Ethylene-propylene Diene Monomer (EPDM), as for liquid EPDM,

it can be used for roof coating Table 9.1: Physical Properties of Elastomer Physical Properties

Natural Rubber

SBR EPDM NBR Neoprene

Specific Gravity 0.93 0.94 0.86 1.00 1.23 Durometer, Range 30-100 40-100 30-90 30-90 40-95 Tensile Strength E F-G VG VG VG Elongation VG-E G G G G Compression Set G G G G F-G

Heat Resistance F F-G VG-E G F-G

Resilience or Rebound

E F-G G F-G VG

Impact Resistance E E G F G Abrasion Resistance E G-E G-E G-E G-E Tear Resistance E F F-G F-G F-G Cut Growth E G G G G

Physical Properties

Natural Rubber

SBR EPDM NBR Neoprene

Flame Resistance P P P P G Impermeability, Gas F F F-G G F-G Weathering Resistance

P-F F E F-G VG

Low Temperature Limit*

-10 TO -50F

0 TO -50F

-20 TO -60F

-30 TO -40

F -10 TO -

50F

High Temperature Limit*

158 TO 225F

158 TO 225F

300 TO 350F

275F 225F

P = Poor, F = Fair, G = Good, VG = Very Good, E = Excellent

9.3 Plastic Plastic is an important group of materials for construction. A plastic is a polymeric (usually organic) of high molecular weight which can be shaped by flow. In general, plastics exhibit a number of outstanding characteristic:

- lightness in weight (generally half as light as aluminum) - high dielectric strength (electric insulation) - low heat conductivity (heat insulation) - special properties toward lights (colorability) - extremely resistant toward chemical - metal insert may be molded into the plastic

(since plastics are inert toward such materials) - many high-quality products can be developed

by using a lathe, sawing, punching and drilling. Organic plastic can be classified into three general classifications which are;

(i) Thermoplastic: an organic plastic, either natural or synthetic, which remain permanently soft at elevated temperatures. Upon cooling, they again become hard. These materials can be shaped and reshaped any number of times by repeated heating and cooling. Some of the most familiar natural thermoplastics include asphalts, bitumen, pitches and resin.

(ii) Thermosetting: an organic plastic that were originally soft or

soften at once upon heating, then harden permanently. Thermosetting plastic are hardened by chemical changes due to

heat, catalyst or to both. Thermosetting plastics remain hardened without cooling and do not soften appreciably when reheated. The most common thermosetting plastic is polyester.

(iii) Chemically Setting Plastic: are those that harden by the addition

of a suitable chemical to the composition just before molding or by subsequent chemical treatment following fabrication.

Properties of Plastic The strength of plastics materials is generally much lower than that of other constructional material. Nevertheless, plastics are light material with relative density between 0.9 and 2.0. Table 9.2 shows the strength-weight relationships for plastic and some common structural elements. Table 9.2: Strength-weight relationships for plastic and some common structural elements.

Material Specific Gravity

Tensile Strength (psi)

Tensile Strength Specific Gravity

Chrome-vanadium steel 7.85 164 000 20 800 Structural Steel 7.83 65 000 8 300 Cast iron, grey 7.03 5 000 5 000 Titanium alloy 4.7 145 000 31 000 Aluminum alloy 2.85 6 000 20 000 Magnesium Alloy 1.81 44 000 24 300 Glass fabric laminate 1.9 45 000 23 600 Asbestos cloth laminate 1.7 9 000 5 300 Paper laminate 1.33 20 000 15 000 Cellulose acetate 1.3 5 000 3 900 Methyl methacrylate 1.18 8 500 7 200 Polystyrene 1.06 5 500 5 200 Polyethylene 0.92 1 300 1 400 Sitka spruce 0.40 17 000 42 500

Application of Plastic Raw materials used in the manufacture of plastics traditionally come from two main sources: i. Animal and vegetable by-products such

as casein (from cows milk), cellulose (mainly from cotton fibers too short for

spinning) and wood pulp, common products being cellulosics. . Petroleum by-products obtained during the refining and cracking of

able 9.3 shows uses of some plastic material

able 9.3: Typical uses of plastic material

iicrude oil, common products being polythene, PVC and polystyrene. This method is responsible for the bulk of plastics manufacture.

T TCompound Typical Uses (A) Vinyl Thermoplastics Polythene HD AcPE LD

id-resisting lining. Babies baths, kitchen and other

ion household ware. Piping, toys, fabric filaments. Sheet, wrapping material, polythene bags, electric insulatink cartridge. Sheets, wrapping material, polythene bags, squeeze bottles, electrical insulation, ink cartridge.

Polystyrene (General purpose)

Ceiling tiles, heat insulation, packaging for fragile equipment

Polyvinyl chloride nd PVC

Domestic/industrial piping (rainwater, waste etc), light fittings, curtain rail (with metal insert). Safety helmets aducting

(B) Thermosetting Plastics Silicones Water-proof coating fabrics. Anti foaming agents. Hydraulic

fluids. Electrical equipment such as switch parts, induction heating equipment, insulation for motors and generator coils.

Epoxides Sold as resins and syrups. Used as adhesive for gluing metal, low-pressure laminations, surface coating, casting and repairing casting.

Polymide Bearings, compressor valves, piston rings, diamond abrasive wheel binders

.4 Polymer

Polymer engineering is generally an engineering field that designs, analyses,

Polymer Materials

The basic division of polymers into thermoplastics and thermosets helps define their areas of application. The latter group of materials includes phenolic resins, polyesters and epoxy resins, all of which are used widely in

9

and/or modifies polymer materials. Polymer engineering covers aspects of petrochemical industry, polymerization, structure and characterization of polymers, properties of polymers, compounding and processing of polymers and description of major polymers, structure property relations and applications.

cetal resin

plastic, a polymer with the

ET stic polymer resin of the polyester

e, rming in

ombination with glass fiber.

Polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains

Ais an engineeringchemical formula -(-O-CH2-)n-. It is often marketed and used as a metal substitute Pis a thermoplafamily and is used in synthetic fibers; beveragfood and other liquid containers; thermofoapplications; and engineering resins oftenc

co fibres such as fibreglass and a hermosetting matrix of these

es more similar to traditional engineering materials like steel. However, their very much lower densities ompared with metals makes them ideal for lightweight structures. In

addition, they suffer less from fatigue, so are ideal for safety-critical parts

uch as tyres. Typical rubbers used conventionally include natural rubber, nitrile rubber, polychloroprene, polybutadiene, styrene-butadiene and

mposite materials when reinforced with stifframids. Since crosslinking stabilises the taterials, they have physical propertim

c

which are stressed regularly in service.

Thermoplastics have relatively low tensile moduli, but also have low densities and properties such as transparency which make them ideal for consumer products and medical products. They include polyethylene, polypropylene, nylon, acetal resin, polycarbonate and PET, all of which are widely used materials.

Elastomers are polymers which have very low moduli and show reversible extension when strained, a valuable property for vibration absorption and damping. They may either be thermoplastic (in which case they are known as Thermoplastic elastomers) or crosslinked, as in most conventional rubber products s

fluorinated rubbers such as Viton.

Applications of Polymer

Typical uses of composites are monocoque structures for aerospace and automobiles, as well as more mundane products like fishing rods and bicycles. The stealth bomber was the first all-composite aircraft, but many

he Airbus uses an increasing proportion of composites in its fuselage. The quite different physical properties of

passenger aircraft like t

composites gives designers much greater freedom in shaping parts, which is why composite products often look different to conventional products. On the other hand, some products such as drive shafts, helicopter rotor blades, and propellers look identical to metal precursors owing to the basic functional needs of such components. See Figure 9.2 and Figure 9.3.

Figure 9.2: B-2 Spirit stealth bomber of the U.S Air Force.

Figure 9.3: A time-trial carbon fibre composite bicycle with aerodynamic wheels and aero bars

Monocoque is a construction technique that supports structural load by using an object's external skin as opposed to using an internal frame or truss that is then covered with a non-load-bearing skin

Stealth bomber is an American heavy bomber with "low observable" stealth technology designed to penetrate dense anti-aircraft defenses and deploy both conventional and

uclear weapons. n

9.5 Gypsum Board

ypsum board is widely used for internal walls and ceilings by the construction

dustry, and is a material of growing importance in the do-it-yourself sector. It is

gypsum into a

semi-hydrous form of calcium H2O). The raw gypsum, CaSO42 H2O, (mined or obtained

from flue gas desulfurization (FGD)) must be calcined before use. The pically paper and/or fiberglass), plasticizer,

G

in

manufactured by calciningplaster, making a slurry from the plaster, and passing the slurry through machines which shape, set, and cut into a board. Also commonly known as drywall, wallboard and plasterboard.

Gypsum Board Manufacture

A gypsum board panel is made of a paper core made primarily from gypsum plaster, thesulfate (CaSO

liner wrapped around an inner

4

plaster is mixed with fiber (tyfoaming agent, potash as an accelerator, EDTA, starch or other chelate as a retarder, various additives that increase mildew and fire resistance (fiberglass or vermiculite), wax emulsion for lower water absorption and water. This is then formed by sandwiching a core of wet gypsum between two sheets of heavy paper or fiberglass mats. When the core sets and is dried in a large drying chamber, the sandwich becomes rigid and strong enough for use as a building material.

Hydrous containing water as a constituent Flue gas desulfurization is the technology used for removing sulfur dioxide (SO2) from the exhaust flue gases in power plants that burn coal or oil to produce steam for the steam turbines that drive their electricity generators

re additives that increase the plasticity or fluidity of the material to which they astics, cement, concrete, wallboa

the coalescence of

the common name given to potassium carbonate and various mined and lts that contain the element potassium in water-soluble form.

Plasticizer aare added, these include pl rd and clay bodies Foaming agent is a surfactant, which when present in small amounts, facilitates the formation

f a foam, or enhances its colloidal stability by inhibiting obubbles Potash ismanufactured sa

EDTA Ethylenediamine tetra-acetic acid, a crystalline acid with a strong tendency to form chelates with metal ions. Starch an odourless, tasteless white substance occurring widely in plant tissue and obtained chiefly from cereals and potatoes. It is a polysaccharide which

s as a carbohydrate store and is an important constituent of the human

helate und containing a ligand (typically organic) bonded to a central metal

whitish coating consisting of minute fungal hyphae, growing on plants or organic material such as paper.

functiondiet. Ca compoatom at two or more point. Mildew a thin

ampd Vermiculite is a natural mineral that expands with the application of heat.

Gypsum Board Waste

Because up to 17% of gypsum board is wasted during the manufacturing and in freq re-sed, disposal can become a problem. Some landfill sites have banned the

dumping of gypsum board. Some manufacturers take back waste gypsum sites and recycle it into new board. Recycled paper

moisture resistance. It is commonly used in washrooms and other areas expected to experience

stallation processes] and the gypsum board material is uently notu

board from construction is typically used during manufacturing. More recently, recycling at the construction site itself is being investigated. There is potential for using crushed gypsum board to amend certain soils at building sites, such as clay and silt mixtures, as well as using it in compost.

Application of Gypsum Board

Regular white board, from 1/4" to 3/4" thickness Greenboard, the drywall that contains an oil-based additive in the green

colored paper covering that provides

elevated levels of humidity. Blueboard, blue face paper forms a strong bond with a skim coat or a

built-up plaster finish providing both water and mould resistance. Cement board, which is more water-resistant than greenboard, for use

in showers or sauna rooms, and as a base for ceramic tile

ent

ed density (CD), also called ceiling board, which is available

.6 Glass

Soundboard is made from wood fibers to increase the sound rating (STC)

Soundproof board is a laminated board made with gypsum, other materials, and damping polymers to significantly increase the STC

Enviroboard, a board made from recycled agricultural materials Lead-lined gypsum board, used around radiological equipm

Foil-backed gypsum board to control moisture in a building or room Controllonly in 1/2" thickness and is significantly stiffer than regular white board

See Figure 9.5 to Figure 9.6

Figure 9.5: Gypsum Board Wall

Figure 9.6: Gypsum Board False Ceiling 9

The principle ingredients of common soda glass re silica sand, lime (from limestone) and soda sh (crude sodium carbonate). Since glass can e recycle, large amount of scrap glass (cullet)

ss manufactured. At 15900C mperature in gas-fired furnaces which hold up

Glass can be rolled, blown, ering point of view, glass is en established to deal with hich is American National aterial Used In Buildings

ules are unable to move ignificant distance relatively at one another making glass extremely brittle at

The rate of viscous flow is dependent mainly upon the evailing temperature but is also dependent upon the composition and

aabare used in glateto 250 tonnes of molten glass, acidic silicate will soda to form the mixed silicates known as glass. cast or pressed for a variety of uses. From engineextremely weak and codes and standard have bethe utilization of glass in engineering project wStandards Institute (ANSI) Z97.1 Safety Glazing MPerformance Specification and Methods of Test. Properties of Glass Glasses are plastic at high temperatures and rigid at low temperatures but under normal manufacturing conditions glasses do not crystallize. When, glasses have no crystal structure making molec

reacts with basic lime and

sambient temperature.prstructure of the glass. Small applied stresses will cause the more highly strained bonds within the structure to be ruptured. When glass is drawn to a fine fiber and cooled quickly, a high tensile strength is produced. Glass is extremely stable and will not deteriorate. Special glasses used in fiber-

reinforced composites can reach strength of up to 15 000 MPa (under ideal condition), but in practice a lower strength of about 3500 MPa would be obtained since surface damage of the fiber is caused by contact with other material. These microscopic surface scratches act as stress-raisers.

Application of Glass

The coefficient of thermal expansion of ordinary soda glass is relatively high,

hilst its thermal conductivity is low, and this combination of properties makes the majority of domestic situation involving sudden

ontact with boiling water. Table 9.4 shows other applications of glass in

wit unsuitable for use incwide range of use. Table 9.4: Properties and Typical Use of Glass

Type of glass Properties and uses

Soda glass Window panes, plate glass, bottle, jar etc. Lead glass High refractive index and dispersive power. Lenses,

lamp, prism and other optics. Crystal glass table-ware Boro-silicate glass nsion and good resistance to

chemical. Used for heat-resistance kitchen-ware and (Pyrex) Low coefficient of expa

laboratory apparatus. Alumino-silicate glass (ceramic glass)

High softening temperature (Tg up to 8000C). A glass-ceramic for cooking ware, heat exchangers etc

High silicon glass Vycor-low coefficient of expansion. Missile noise cones, window for space vehicles

Silicon-free glass Sodium vapour discharge lamp T mmon metals when under the action of applied forces. Such difference can be classified as follows:

ient and

Even the most brittle of metal show some plastic flow;

here is little in co between mechanical properties of glasses and

(i) under short-time testing methods, glasses are brittle at amb

temperatures. They are elastic right up to the point of fracturefail without any previous yield or plastic deformation (Figure 9.7).

(ii) although an external load may be applied in compression, failure in glass always results from a tensile component of the stress. The strength of such materials can therefore best be described in terms of tensile strength;

(iii) the time for which a static load is applied has a great influence on the strength of glass in the long term. Thus the extrapolated infinite-time modulus of rupture for glasses is usually between a third and a half of that for short-time loading.

9.7 Fiber Reinforced Polymer (FRP)

iber Reinforced Polymer (FRP) made of a combination of continuous fiber mbedded in resin matrix is an advanced composite material that has been

material. Some of the advantages f FRP are high tensile strength, lightweight, non-magnetic and durable.

ber, resins, interface, fillers, and additives. Higher modulus fibers contribute ereas the matrix helps to transfer

r distribute the stress from one fiber to another, through interface shear

Feidentified as a potential new construction oSince it is a non-corrodible material it may be used as reinforcement in concrete member. The most commonly available FRPs, which can be used for civil infrastructure, are glass (GFRP), carbon (CFRP) and aramid (AFRP).

Properties of Fiber Reinforced Polymer Advanced FRP composites are made from different constituent materials, i.e. fito the mechanical strength of the FRP, whoresistance, and to improve the durability of the fiber against environmental and mechanical damage. The fiber generally occupies 3070% of the matrix volume of the composite (Figure 9.8). The interface between the fiber and the matrix is known to significantly affect the performance of FRP composites. In addition to these three basic components (fibers, resins, and interface), the fillers serve to reduce cost and shrinkage. The additives help to improve the mechanical and physical properties of the composites as well as the workability.

Applications of Fiber Reinforced Polymer

The scope of applications of FRPs in concrete construction is very wide. In ct, the true potential of FRP is yet to be realised. From the basic application

three basic forms:

e

fapoint of view, FRPs can be used in concrete in Internal reinforcement for reinforced concrete structures; External reinforcement for strengthening or repairing existing deficient

structures; FRP structural elements (e.g. beams, girder, and column) in concrete

FRP composite structures. Figure 9.10 shows typical varieties of FRP reinforcements for civil infrastructure applications. Figure 9.11 illustrates GPRP reinforcing bars for us in concrete.

Figure 9.10: FRP reinforcements for civil infrastructure application

FRP reinforcement, external to a concrete structure, can be effective in the form of external plate bonding or fiber wrapping. External plate bonding by dhesive is a well established technique to strengthen or repair deficient inforced concrete beams or slabs. Initially the method was developed with

g of concrete structures. This method is an alternative to the steel cket technique. The application of FRP external reinforcement has a long-

aresteel plates but, at present, CFRP plates are being widely used all over the world. The wrapping of concrete columns by resin impregnated FRP fabrics or straps to improve the strength and ductility is a technique used in seismic retrofittinjaterm durability advantage, and a great potential to be used extensively to strengthen or upgrade ageing reinforced concrete infrastructure facilities. Figure 9.12 shows the wrapping technique used for column rehabilitation.

Figure 9.12: Concrete columns reinforced with FRP sheets

Tutorial 9 1. Briefly define:

b. Plastic

oard

olymer

d g rial.

2. ards for bituminous. Give the purpose and procedure for each test.

4. anic plastics. utilized today.

s in construction

a. Bitumen

c. Polymer d. Gypsum Be. Glass f. Fiber Reinforced P an ive two uses of each mate

Discuss the specific ASTM stand

3. List seven outstanding characteristics of plastics. List three general classifications of org

5. List and discuss the four types of glazing material 6. Discuss the main application of FRP component

application.

1. Materials For Engineers and Technicians, Raymond A. Higgins,

Newnes, 2006 th2. Materials For Civil & Highway Engineers, 4 ed., Kenneth N. Derucher,

Prentice Hall, 1998 Properties of En3. gineering Materials, R.A. Higgins, Edward Arnold, 1994

4. Introduction to Engineering Materials, V. B. John, English Language Book Society, 1983

9.1. Bitumen Bitumen Application Bitumen alternatives Polymer Materials Applications of Polymer Gypsum Board Manufacture Gypsum Board Waste