DIV 3

Lime

One of the oldest manufactured building materials used as a mortar and plaster by all the early civilizations. Manufactured by the calcination of limestone (carbonates of calcium and magnesium).

Quicklime

By-product of the decomposition of lime carbonates into carbon dioxide and calcium oxide.

Slaking (Hydration)

Mixing of quicklime with water prior to being used.

Slaked Lime

Also known as Calcium Hydroxide.

Hydrated Lime

Used as an ingredient of hard-finish coat for two-and three-coat Portland cement plasters. It is also used for mixing with cement mortar or concrete to: increase its workability, decrease its permeability to water, reduce cracking due to shrinkage.

Hydraulic Lime

A type of lime which will set under water and is used only where slow underwater setting is required.

Gypsum Rock

Ground fine and heated (calcined) between 325 Deg F to 340 Deg F when it loses about three-fourths of its combined water.

Plaster of Paris

Remaining product of heating gypsum rock where pure gypsum is used.

Hard Wall Plaster

Remaining product of heating gypsum rock where 39.5% of impurities are present.

Gypsum Plaster

Rendered more plastic by the addition of hydrated lime. Fiber or hair is also sometimes added for greater cohesiveness.

Cement

First developed by the Romans by mixing slaked lime with pozzolana which hardened under water.

Pozzolana

Volcanic ash.

Portland Cement

Obtained by finely pulverizing clinker produced by calcining a proportioned mixture of argillaceous (silica, alumina) and calcareous (lime) materials with iron oxide and small amounts of other ingredients.

Surfate-Resisting Cement

Type of Portland cement used for applications where alkaline water and soils occur.

White Cement

Type of Portland cement which is free from iron impurities.

Cement

Should be protected at the building site from injury through contact with dampness and should be stored in shed with a wood floor raised about 300mm (12") from the ground.

Warehouse Set

When the cement is stored in high piles for long periods, there is a tendency for the lower layers to harden caused by the pressure above.

Concrete

A proportioned mixture of cement, aggregate and water.

Setting

The hardening of concrete.

Mortar

Concrete mixed with water and a fine aggregate of less than 6mm (¼").

Reinforced Concrete

Concrete strengthened by embedded steel.

Plain Concrete

Concrete without reinforcement.

Aggregate

Inert mineral fillers used with cement and water in making concrete, should be particles that are durable strong, clean, hard and uncoated, and which are free from injurious amount of dusts, lumps, soft and flaky particles, shale, alkali, organic matter loam or other deleterious substances.

Fine Aggregate

Aggregates smaller than 6mm (¼") in size. Consist of sand, stone screenings or other inert materials of similar characteristics. 80 to 95% shall pass a No. 4 wire cloth sieve and not more than 30% nor less than 10% shall pass a No. 50 sieve.

Coarse Aggregate

Aggregate larger than ¼" in size. Consists of crushed stones, gravel or other inert materials of similar characteristics.

Special Aggregate

Include cinders, blast furnace slag, expanded shale or clay, perlite, vermiculite, and sawdust. May produce lightweight, nailable concrete and thermal insulating concrete.

Slump Test

Used for measuring the consistency of a concrete mix

Consistency

Defined as the "state of fluidity of the mix", and includes the entire range of fluidity from the wettest to the driest possible mixtures.

Proportioning by Arbitrary Proportions

Method of proportioning concrete where aggregates are measured by loose volume, that is, its volume as it is thrown into a measuring box.

Class AA

1 part cement : 1.5 parts sand : 3 parts gravel concrete proportion used under water, and for retaining walls.

Class A

1 part cement : 2 parts sand : 4 parts gravel concrete proportion used for suspended slabs, beams, columns, arches, stairs, walls of 100mm (4") thickness.

Class B

1 part cement : 2.5 parts sand : 5 parts gravel concrete proportion used for walls thicker than 100mm (4"), footings, steps, reinforced concrete slabs on fill.

Class C

1 part cement : 3 parts sand : 6 parts gravel concrete proportion used for concrete plant boxes, and any non-critical concrete structures.

Class D

1 part cement : 3.5 parts sand : 7 parts gravel concrete proportion used for mass concrete works.

Proportioning by Water-Ratio and Slump Test

Method of proportioning concrete by selecting the amount of water to be added to the cement to give the desired strength and adding just enough mixed aggregate to the water and cement to give a concrete mix the desired consistency.

Proportioning by Water-Ratio, Slump Test and Fineness Modulus

Method of proportioning concrete by selecting the amount of water to be added to the cement to give the desired strength, adding proportions of fine and coarse aggregate determined by the fineness modulus method.

Batch Mixer

Class of concrete mixer where sufficient materials are placed at one time to make a convenient size batch of concrete, the whole amount being discharged in one mass after it is mixed.

Continuous Mixer

Class of concrete mixer where materials are fed constantly and from which the concrete is discharged in a steady stream.

Drum Mixer

Most common type of continuous concrete mixer.

Shrinkage Crack

Likely occurs at joints where fresh concrete is joined to concrete which has already set, and hence in placing the concrete, construction joints should be made on horizontal and vertical lines.

Hardening

Process wherein cement and water unite to form compounds that give strength and durability to the concrete. It continues as long as the temperatures are favorable and moisture is present.

Compressive Strength

Concrete curing property that reaches about 60% of its own maximum value at an age of 28 days and about 80% at an age of 3 months.

Admixture

Substance added to cements, mortars, and concrete for the purpose of improving or imparting particular properties.

Accelerator

Concrete admixture used to speed up setting time, to develop earlier strength, and to reduce length of time for protection.

Accelerator

Concrete admixture that increase the expansion and contraction of concrete, reduce resistance to sulfate attack, and increases efflorescence and corrosion of high tension steels.

Retarder

Concrete admixture used to slow down the hydration of the cement during very hot weather. Principal ingredients include zinc oxide, calcium lignosulfonate, derivatives of adipic acid.

Retarder

Concrete admixture that causes some loss of early strength and will therefore require careful control and more frequent slump tests, also reduces the expansion and contraction of concrete.

Air-Entraining Agent

Concrete admixture that introduce minute air bubbles to greatly increase the resistance of concrete to freezing and thawing, increase plasticity and reduce bleeding.

Air-Entraining Agent

Concrete admixture that require careful control and more frequent slump tests.

Inert, Finely Divided Powders

Concrete admixture added to improve workability, used as per manufacturer's directions

Waterproofing Compounds

Concrete admixture used to reduce the capillary attraction of the voids in the concrete or mortar. They are manufactured from stearic acid or its compounds, mainly calcium steareate, and include asphalt emulsions.

Colored Pigments

Mainly to used to give color to concrete floors.

Dry-cast, Broadcast or Dust-On

Used for surface coloring. They are dusted on, usually in two coats, after all surface water has disappeared.

Integral Colors

Used for body coloring and are incorporated in the mortar topping.

Plasticizing Agent

Used to lower water cement ratio and make the mix more workable.

Kiln-Dried Lumber

Type of lumber with tendency to swell when soaked by the concrete, causing bulging and distortion of forms.

Green Lumber

Type of lumber which dries out and shrinks if allowed to stand too long before the concrete is placed.

Petroline

Used to preserve the lumber forms against damage by alternate wetting and drying.

Plywood

Concrete form which works best where a smooth surface is required.

Steel

May be in the form of pans for concrete joist construction or steel decking or corrugated steel for concrete slabs and slab-and-joist construction.

Plastic

Concrete form including polystyrene

Aerocrete

Light-weight, expanded structural concrete produced by adding a small amount of metallic aluminum powder to the mixture of Portland cement and sand of cinders.

Gunite

Mixture of sand and cement deposited under high pneumatic pressure with a machine manufactured under the trade name Cement Gun, to which the required supply of water is added just before the dry constituents emerge from nozzle.

Aerocrete

Type of processed concrete used for structural floor and roof slabs, partition blocks for sound proofing, wall insulation, in rooms of refrigerator plants, lightweight fill on top of structural floor and roof slabs.

Gunite

Type of processed concrete used for encasing structural steel, when reinforced, for floor and roof slabs and curtain walls. Ideal for swimming pool construction.

Porete

A Portland cement concrete to which a chemical foam is added to generate gases in the process of deposition, resulting in light weight precast or shopmade unit in both hollow and solid forms.

Haydite

This is processed concrete added with lightweight aggregate.

Pumice

Lightweight aggregate weighing from 25 to 60 lbs.per cu. ft. with an undesirable feature of water absorption.

Perlite

Lightweight aggregate composed of stable silicates, and is inert and thus durable for use as a lightweight aggregate or for insulation. Its disadvantages are its friability, small particle size, and extreme lightness

Vermiculite

A micaceous mineral which expands on application of heat to as much as 30 times its original volume.

Vermiculite

Used as an aggregate in concrete fireproofing steel, for floor and roof fill, and for acoustic and fireproof plaster.

Clay, Shale Aggregate

Includes airox, rocklite, diatomite, and haydite.

Expanded Slag

Made by treating molten blast furnace slag with controlled quantities of water or steam.

Foamed Slag

By-product lightweight aggregate used for precast blocks, cast-inplace walls of houses and for panel filling of steel-framed buildings.

Cinders

Composed of the ash components of the coal along with the various quantities of unburned or partially burned combustible matter.