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GLASSFIBER REINFORCED PLASTICS (GRP)

INTRODUCTION

Glass-reinforced plastic (GRP) is a composite material or fiber-reinforced

plastic made of a plastic reinforced by fine glass fibers. Like graphite-reinforced

plastic, the composite material is commonly referred to by the name of its

reinforcing fibers (fiberglass). Thermosetting plastics are normally used for

GRP productionmost often unsaturated polyester(using 2-butanone

peroxide aka MEK peroxide as a catalyst) , butvinylester or epoxy are also used.

Traditionally, styrene monomer was used as a reactive diluent in the resin

formulation giving the resin a characteristic odor. More recently alternatives have

been developed. The glass can be in the form of a chopped strand mat (CSM) or a

woven fabric.

As with many other composite materials (such as reinforced concrete), the two

materials act together, each overcoming the deficits of the other. Whereas the

plastic resins are strong in compressive loading and relatively weak in tensile

strength, the glass fibers are very strong in tension but have no strength against

compression. By combining the two materials, GRP becomes a material that

resists both compressive and tensile forces well. The two materials may be used

uniformly or the glass may be specifically placed in those portions of the structure

that will experience tensile loads.
http://maps.thefullwiki.org/Composite_materialhttp://maps.thefullwiki.org/Fiber-reinforced_plastichttp://maps.thefullwiki.org/Fiber-reinforced_plastichttp://maps.thefullwiki.org/Plastichttp://maps.thefullwiki.org/Graphite-reinforced_plastichttp://maps.thefullwiki.org/Graphite-reinforced_plastichttp://maps.thefullwiki.org/Thermosetting_plastichttp://maps.thefullwiki.org/Unsaturated_polyesterhttp://maps.thefullwiki.org/2-butanone_peroxidehttp://maps.thefullwiki.org/2-butanone_peroxidehttp://maps.thefullwiki.org/MEK_peroxidehttp://maps.thefullwiki.org/Vinylesterhttp://maps.thefullwiki.org/Epoxyhttp://maps.thefullwiki.org/Styrene_monomerhttp://maps.thefullwiki.org/Reactive_diluenthttp://maps.thefullwiki.org/Reinforced_concretehttp://maps.thefullwiki.org/Physical_compressionhttp://maps.thefullwiki.org/Tensile_strengthhttp://maps.thefullwiki.org/Tensile_strengthhttp://maps.thefullwiki.org/Tensile_strengthhttp://maps.thefullwiki.org/Tensile_strengthhttp://maps.thefullwiki.org/Physical_compressionhttp://maps.thefullwiki.org/Reinforced_concretehttp://maps.thefullwiki.org/Reactive_diluenthttp://maps.thefullwiki.org/Styrene_monomerhttp://maps.thefullwiki.org/Epoxyhttp://maps.thefullwiki.org/Vinylesterhttp://maps.thefullwiki.org/MEK_peroxidehttp://maps.thefullwiki.org/2-butanone_peroxidehttp://maps.thefullwiki.org/2-butanone_peroxidehttp://maps.thefullwiki.org/Unsaturated_polyesterhttp://maps.thefullwiki.org/Thermosetting_plastichttp://maps.thefullwiki.org/Graphite-reinforced_plastichttp://maps.thefullwiki.org/Graphite-reinforced_plastichttp://maps.thefullwiki.org/Plastichttp://maps.thefullwiki.org/Fiber-reinforced_plastichttp://maps.thefullwiki.org/Fiber-reinforced_plastichttp://maps.thefullwiki.org/Composite_material


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Also take a look at our construction profiles:- Angles

- C-Profiles

- Flat profiles

- Hat-Profiles- Rectangle tubes

- Rods

- T-Profiles

- Tubes

- U-Channels

- Z-Profiles

Uses

Uses for regular fiberglass include mats, thermal insulation, electrical insulation,

reinforcement of various materials, tent poles, sound absorption, heat- and

corrosion-resistant fabrics, high-strength fabrics, pole vault poles, arrows, bows

and crossbows, translucent roofingpanels, automobile bodies, hockey

sticks, surfboards and boat hulls. Ithas been used for medical purposes in casts.

Fiberglass is extensively used for making FRP tanks and vessels. Fiberglass is also

used in the design ofIrish stepdance shoes.

SPECIFICATION

GENERAL

All Glass Reinforced Plastic (GRP) Products shall be designed in the Supply and

Installation of Glass (or Fibre) Reinforced Plastic Units category of the list of

approved Suppliers of Materials and Specialist Contractors for Public Works of

HKSAR Government. The Contractor should be in the approved list of registered

sub-contractor under PROVISIONAL CONSTRUCTION INDUSTRY CO-ORDINATION

BOARD of Hong Kong and should have more than 20 years proven solid

experiences on manufacturing GRP Products. ISO 9001:2000 certification must be

obtained and submitted in tender stage.
http://maps.thefullwiki.org/Thermal_insulationhttp://maps.thefullwiki.org/Insulator_(electrical)http://maps.thefullwiki.org/Surfboardhttp://maps.thefullwiki.org/FRP_tanks_and_vesselshttp://maps.thefullwiki.org/Irish_stepdancehttp://maps.thefullwiki.org/Irish_stepdancehttp://maps.thefullwiki.org/FRP_tanks_and_vesselshttp://maps.thefullwiki.org/Surfboardhttp://maps.thefullwiki.org/Insulator_(electrical)http://maps.thefullwiki.org/Thermal_insulation


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PERFORMANCE

(1) The design loads and effects for the Products including fixings and supports

shall be those specified by the Consulting Engineer.

(2) The maximum deflection shall not exceed 1% of the span measured betweencentres of consecutive supports.

GRP MATERIAL AND PROFILES

Glass Reinforced Plastic Sheets to Quality Control BS 4154: Part 1 with thermo-

setting polyester resin to BS 3532:

(a) Profile : as shown on the drawing;

(b) Light Diffusion Class : Very heavily diffusing;

(c) Colour : To approval

(d) GRP Shall be ultra-violet resistant and special high quality pigment shall be

adopted for the gel coat layer to avoid rapid discoloring

(e) GRP shall have a hardness, as measured by the Barcol test, of 35 minimum

(f) Colour shall be uniform across the GRP panel

(g) The Contractor shall provide setting drawings, templates, directions, and

similar aids for ensuring adequate / proper support of the work.

(h) The surface of the GRP panel shall exhibit no sign of crazing on any surface. (i)

Fulfill Impact Test based on BS 6206 and must be carried out by the University of

Hong Kong

(j) GRP external finish shall be in a plain gloss colour with an isophthalic colours

fast gel coat. Colour shall be to the Engineers approval.

(k) GRP internal finish shall be a coloured stipple finish to the Engineers approval.

(l) The Contractor shall be responsible for the establishment of panel dimensions

based upon site measurement..


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(m) A full scale sample panel for each panel shall be submitted to the Engineer for

approval of colour, texture, finish, consistency and tolerance prior to production

and incorporation in the works. The place of inspection shall be approved by the

Engineer.

(n) The Contractor shall submit to the Engineer copies of the GRP manufacturers

record sheets for each unit produced stating:

(i) Details of casting (ii) Resin Mix and Type (iii) Mass of fibre and Type (iv) Panel

Weight

(v) Detail of finishes

(vi) Mechanical Properties Test Report

GRP Panel must have the following mechanical properties (Yeungs Test Report)

Type of GRP Laminate = 35% glass content by weight Tensile Strength = 171

Nmm-2 Elongation = 1.8 % Tensile Modulus = 12600 Nmm-2 Compress Strength =

102 Nmm-2 Flexural Strength = 250 Nmm-2 Flexural Modulus = 12810 Nmm-2

Inter-laminate Shear Strength = 18.5 Nmm-2

(o) Marked with the manufacturers name or trademark, the BS number 4154 and

the designation of samples tested to BS 476: Part 3

(p) GRP Products shall comply with Fire Retardant Requirement BS 476 Part 3, 6and 7 Standard and test reports of these tests shall be submitted in tender

ATTACHMENT OF GRP

(a) Layout and install each item in accordance with approved shop drawing

(b) Space screw fasteners at 300mm c.c max. around GRP units

(c) At all exposed screw fasteners locations, countersink the GRP and set the

screw heads below the finish surface


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FINISHING OF JOINTS

(a) Fit GRP units as tightly together as possible along joint lines

(b) Where butt joint result in a gap less than 6mm its widest point, fill the opening

with resin paste with pigmented colour.

(c) Where butt joint result in a gap 6mm or wider at its narrowest point, fill the

opening with chopped strand mat and resin paste with pigmented colour

(d) Finish all joint surfaces, including screw fastener depressions, to match

adjacent GRP unit surfaces.

(e) Sand the surfaces before any finish is applied.

(f) Prepare joint surfaces as specified for other surfaces, and apply paintingmaterials to match and blend with adjacent finishes such that joint lines will be

imperceptible in the finish work.

SITE DELIVERY AND STORAGE

(1) Before delivery to Site the Contractor shall set aside an area for storage of the

GRP units (2) The storage area shall be dry, protected from direct sunlight, secure

and clearly designated for the sole purpose of storing GRP units.

(3) During storage the GRP units shall be supported along the edges over their full

length and kept out of direct sunlight. Separating pieces, to the manufacturersrecommendations, shall be inserted between all units.

ERECTION OF GRP UNITS

(1) All GRP units shall be protected against damage during transport storage and

construction operations as recommended by the manufacturer until handover of

the structure to the Employer.

(2) The handling and method of erection of the GRP units shall be to the

manufacturers recommendations.


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CLEANING OF GRP UNITS

(1) The GRP units shall be hosed down with clean fresh water to remove any dust

build up.

(2) No abrasive materials or scouring action shall be used which will score thesurface.

(3) For removal of any stubborn dirt the manufacturer shall be consulted for

recommendations.


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HOLLOW AND CEMENT CONCRETE BRICKS

INTRODUCTION

Cement concrete hollow blocks have an important place in modern buildingindustry. They are cost effective and better alternative to burnt clay bricks by

virtue of their good durability, fire resistance, partial resistance to sound, thermal

insulation, small dead load and high speed of construction. Concrete hollow

blocks being usually larger in size than the normal clay building bricks and less

mortar is required, faster of construction is achieved.

Also building construction with cement concrete hollow blocks provides facility

for concealing electrical conduit, water and sewer pipes wherever so desired and

requires less plastering.

MARKET & DEMAND ASPECTS

Cement concrete hollow blocks are modern construction materials and as such

are used in all the constructions viz. residential, commercial and industrial

building constructions. Construction industry is a growing a sector. The demand

for this product is always high in all cities and other urban centres due to

construction of residential apartments, commercial buildings and industrial

buildings.

Growing public awareness of the advantages of the product coupled with increase

in the government and financial institutions support for housing which is a basic

human necessity would ensure a healthy growth in the demand.


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Sl Description of the activity Time (approx.)

1 Selection of the product

1 month

2 Preparation of the project report

3 Selection of the location

4 Registration of enterprise with DIC

5 Mobilising finance for the project

4 months

6 Purchase of land

7 Construction of building

8 Procurement of machinery and equipment

9 Obtaining EB connection

10 Erection and commissioning of machineryand equipment

11 Recruitment of manpower

12 Trial run and commencement of production

Total project implementation period 6 months


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RAW MATERIALS

Concrete is a mixture of ordinary Portland cement, mineral aggregate (sand andstone chips) and water. The water used in preparing the concrete serves two

purposes:

(1) It combines with the cement to form a hardened paste

(2) It lubricates the aggregates to form a plastic and workable mass

The water that combines with the cement varies from about 22 to 28% of the

total amount of mixing water in concrete.

Mineral aggregates (sand and stone chips) are normally divided into two fractions

based on their particle size. Aggregate particles passing through the No.4 or 4.7

mm Indian Standard sieve are known as fine aggregate. The particles retained on

this sieve are designated as coarse aggregate. Natural sand is often used as fine

aggregate in cement concrete mixture. Coarse aggregate are crushed stone chips.

Crushed stone chips broken into particle sizes passing through the 4.7 mm sieve

may also be used as fine aggregate. The maximum size of the coarse aggregate

that may be used in cement concrete hollow blocks is 12.5 mm. However, the

particle size of the coarse aggregate should not exceed one third thickness of the

thinnest web of the hollow blocks.

Ordinary Portland cement is the cementing material used in cement concrete

hollow blocks. Cement is the highest priced material per unit weight of the

concrete. Hence, the fine and coarse aggregates are combined in such

proportions that the resulting concrete is workable and has minimum cement

content for the desired quality.


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MANUFACTURING PROCESS

The process of manufacture of cement concrete hollow blocks involves the

following 5 stages;

(1) Proportioning

(2) Mixing

(3) Compacting

(4) Curing

(5) Drying

(1) Proportioning:

The determination of suitable amounts of raw materials needed to produce

concrete of desired quality under given conditions of mixing, placing and curing is

known as proportioning. As per Indian Standard specifications, the combined

aggregate content in the concrete mix used for making hollow blocks should not

be more than 6 parts to 1 part by volume of Portland cement. If this ratio is taken

in terms of weight basis this may average approximately at 1:7 (cement :

aggregate). However, there have been instances of employing a lean mix of as

high as 1:9 by manufacturers where hollow blocks are compacted by power

operated vibrating machines. The water cement ratio of 0.62 by weight basis can

be used for concrete hollow blocks.

(2) Mixing

The objective of thorough mixing of aggregates, cement and water is to ensure

that the cement-water paste completely covers the surface of the aggregates. All

the raw materials including water are collected in a concrete mixer, which is

rotated for about 1 minutes. The prepared mix is discharged from the mixer

and consumed within 30 minutes.


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(3) Compacting

The purpose of compacting is to fill all air pockets with concrete as a whole

without movement of free water through the concrete. Excessive compaction

would result in formation of water pockets or layers with higher water contentand poor quality of the product.

Semi-automatic vibrating table type machines are widely used for making cement

concrete hollow blocks. The machine consists of an automatic vibrating unit, a

lever operated up and down metallic mould box and a stripper head contained in

a frame work.

Wooden pallet is kept on the vibrating platform of the machine. The mould box is

lowered on to the pallet. Concrete mix is poured into the mould and evenly

levelled. The motorised vibrating causes the concrete to settle down the mould

by approximately 1 to 1 inches. More of concrete is then raked across the

mould level. The stripper head is placed over the mould to bear on the levelled

material. Vibration causes the concrete come down to its limit position. Then the

mould box is lifted by the lever. The moulded hollow blocks resting on the pallet is

removed and a new pallet is placed and the process repeated. The machine can

accommodate interchangeable mould for producing blocks of different sizes of

hollow or solid blocks.

(4) Curing

Hollow blocks removed from the mould are protected until they are sufficiently

hardened to permit handling without damage. This may take about 24 hours in a

shelter away from sun and winds. The hollow blocks thus hardened are cured in a

curing yard to permit complete moisturisation for atleast 21 days. When the

hollow blocks are cured by immersing them in a water tank, water should be

changed atleast every four days.


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The greatest strength benefits occur during the first three days and valuable

effects are secured up to 10 or 14 days. The longer the curing time permitted the

better the product.

(5) Drying

Concrete shrinks slightly with loss of moisture. It is therefore essential that after

curing is over, the blocks should be allowed to dry out gradually in shade so that

the initial drying shrinkage of the blocks is completed before they are used in the

construction work. Hollow blocks are stacked with their cavities horizontal to

facilitate thorough passage of air.

Generally a period of 7 to 15 days of drying will bring the blocks to the desired

degree of dryness to complete their initial shrinkage. After this the blocks are

ready for use in construction work.

QUALITY SPECIFICATIONS

IS 2185

Concrete Masonry Units - Specification - Part 1 : Hollow and Solid Concrete Blocks

(Third Revision)

The above standard specifies requirements for these parameters: dimensions,

grades of hollow blocks, blocks density, compressive strength, water absorption,

drying shrinkage, and moisture movement

UTILITIES

Electrical Power requirement: 25 HP power for industrial purpose is required.

Water: water used in making concrete should be free from acids, alkalis, oil,

dissolved carbon dioxide and decayed vegetable matter. Generally, water suitable

for human consumption is considered adequate for concrete mixing.

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