Concrete Alliance » concrete

Future of Construction Process: Concrete Printing

admin — Wed, 08 Sep 2010 22:19:44 +0000

Concrete Printing Process developed at Loughborough University in the UK is capable of producing building components with a degree of customisation that has not yet been seen. It could create a new era of architecture that is adapted to the environment and fully integrated with engineering function. Web: www.buildfreeform.com

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PRESTRESSED CONCRETE

admin — Tue, 07 Sep 2010 00:48:27 +0000

There are two basic concepts which are generally applied in practice in the field of structural concrete construction and they are; (1) conventionally reinforced and (2)Prestressed concrete.

In prestressed concrete we find the predetermined forces forced on the concrete structural member by special high-tensile steels giving maximum strength with a minimum quantity of steel and this gives an outcome of significant savings in steel tonnage and cost. These anticipatory prestressing forces are calculated and positioned to mitigate the anticipated stresses that occur during the service loading of the member, thus results in reducing the net final stresses developed and allowing a noteworthy decrease in the essential size of the concrete elements.

In general, the prestressing steel strength is approximately 4.5 times tough than regular reinforcing steel. We find that in long-line pre-casting mass-production operations the Pre-stressed beams and slabs are the most economically applied. Large reductions in labor, formwork, and hardware costs can be realized due to the inherent efficiencies of these mass-production techniques,

Also there are floating platforms to exploit the greatest source of energy in the world, for the support of ocean thermal energy conversion (OTEC) plants are also being planned with prestressed concrete for the main hull structure.

The economic and environmental benefits of prestressed concrete can be significant if a coordinated Structural Engineering educational program is given impetus.

Advantages of Prestressed concrete

Section remains uncracked under service loads
High span-to-depth ratios
Suitable for precast construction

Types of Prestressing of concrete

(1) External or internal prestressing

This classification is based on the location of the prestressing tendon with respect to the concrete section.

(2) Pre-tensioning or post-tensioning

This is the most important classification and is based on the sequence of casting the concrete and applying tension to the Tendons.

(3) Linear or circular prestressing

This classification is based on the shape of the member prestressed.

(4) Full, limited or partial prestressing

Based on the amount of prestressing force, three types of prestressing are defined.

(5) Uniaxial, biaxial or multi-axial prestressing

As the names suggest, the classification is based on the directions of prestressing a member.

CNS Infra is gujarat’s first infrastructure company who has implement prestressed concrete and in the form of structural Engineering.

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Concrete Driveway Staining.wmv

admin — Mon, 23 Aug 2010 22:19:02 +0000

concrete-floor-stains.com This video will give a step by step detailed account of the process of staining and sealing a concrete driveway. This method can be used for any exterior concrete surface

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Fab Form FF62-120 FastFoot Concrete Footing Form Fabric

admin — Thu, 12 Aug 2010 21:43:20 +0000

62″x120′ footing fabric
A revolutionary alternative to traditional footing form
Use for footings, tilt footings, grade beams, steps, pad edging, etc
Manufactured from high-strength fabric, FastFoot is stocked in 120′ lengths in widths of 50″ and 62″
Can be retailed either complete or by the foot

Product Description
A revolutionary alternative to traditional footing form. Use for footings, tilt footings, grade beams, steps, pad edging, etc. Manufactured from high strength fabric, FastFoot is stocked in 120′ lengths in widths of 50″ and 62″. Can be retailed either com… More >>

Fab Form FF62-120 FastFoot Concrete Footing Form Fabric

Technorati Tags: concrete, Fabric, FastFoot, FF62120, footing, form

Council will refurbish Chifley concrete slab

admin — Wed, 11 Aug 2010 22:26:51 +0000

Council will refurbish Chifley concrete slab
A CONCRETE slab believed to have been laid by former prime minister Ben Chifley will be refurbished by new concreting works after it was found to be unsafe.

RBM Foam Concrete Machine at Site Project

admin — Wed, 11 Aug 2010 21:45:46 +0000

Advantages of using RBM Building System: 1.Good quality of finishing and straight wall 2.The concrete wall is 4hours fire rated,has a very good insulation on building. 3.Doesnt need thick plastering.(Just apply a layer of finishing coat) 4.Replace brick/block works. 5.Require small number of worker to operate the whole system. 6.Easy & Faster way to do the job. Note:DOESNT REQUIRE MOBILE CRANE OR CONCRETE TRUCK… Company web: www.rbm.com.my Products: www.rbm.com.my RBM Youtube Home: www.youtube.com

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I I want to know to make concrete slabs. The mix design procedure & calculations should be in SI units.?

admin — Fri, 06 Aug 2010 22:17:19 +0000

This is for my civil engineering assignment. I am assigned to make a concrete slab with comressive strength 10N/mm square. If possible, the mix design procedure should come with calculations such as aggregates’ weight and proportions, water-cement ratio, apparent specific gravity etc. Thank you.

Technorati Tags: Calculations, concrete, design, know, procedure, should, slabs, Units, want

Polymer concrete

admin — Sun, 01 Aug 2010 21:42:48 +0000

Composition

In polymer concrete,thermosetting resins are used as the principal polymer component due to their high thermal stability and resistance to wide variety of chemicals. Polymer concrete is also composed of aggregates that include silica, quartz, granite, limestone, and other high quality material. The aggregate must be of good quality, free of dust and other debris, and dry. Failure of these criteria can reduce the bond strength between the polymer binder and the aggregate.

Uses

Polymer concrete may be used for new construction or repairing of old concrete. The adhesion properties of polymer concrete allow patching for both polymer and cementious concretes. The low permeability of polymer concrete allows it to be used in swimming pools, sewer pipes, drainage channels, electrolytic cells for base metal recovery, and other structures that contain liquids. Also as a replacement for asphalt pavement, for higher durability and higher strength.

Advantages

Advantages of polymer concrete include:

Rapid curing at ambient temperatures

High tensile, flexural, and compressive strengths

Good adhesion to most surfaces

Good long-term durability with respect to freeze and thaw cycles

Low permeability to water and aggressive solutions

Good chemical resistance

Good resistance against corrosion

Lightweight

May be used in regular wood and steel formwork

May be vibrated to fill voids in forms

Allows use of regular form-release agents

Dialectric

Disadvantages

Some safety issues arise out of the use of polymer concrete. The monomers can be volatile, combustible, and toxic. Initiators, which are used as catalysts, are combustible and harmful to human skin. The promoters and accelerators are also dangerous.

Polymer concretes also cost significantly more than conventional concrete.

Specifications

Following are some specification examples of the features of polymer concrete:

Density

kg/m3

Compressive strength

MPa

2260
37
This section requires expansion.

References

^ Design and manufacture of hybrid polymer concrete bed for high-speed CNC milling machine Jung Do Suh Dai Gil Lee

^ The compressive strength of a new ureaformaldehyde-based polymer concrete A. A. Alzaydi, S. A. Shihata1 and T. Alp (in table Properties of polymer concrete)

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Technorati Tags: concrete, Polymer

Black & Decker The Complete Guide to Masonry & Stonework: Includes Decorative Concrete Treatments

admin — Mon, 05 Jul 2010 21:42:33 +0000

ISBN13: 9781589232822
Condition: NEW
Notes: Brand New from Publisher. No Remainder Mark.

Product Description
Modern Methods for Classic Concrete!This revision of Black & Decker The Complete Guide to Home Masonry updates much of what made the original book a best-seller, but also answers the latest building trends by featuring exciting new information and projects . In addition to the tried and true project information on building with concrete, brick and block, the book features all new, state-of-the-art information on decorative concrete finishes, including acid co… More >>

Black & Decker The Complete Guide to Masonry & Stonework: Includes Decorative Concrete Treatments

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How to cast a solid ground floor concrete slab

admin — Sun, 04 Jul 2010 21:42:40 +0000

Ground floor concrete slabs are laid on natural ground levels. This are are normally cast after completion of the foundation works. There is a difference between them and basement floors. Basements are done below ground level and they are formed above. They can be used in houses, garden sheds and outdoor houses. When casting them the level should be reduced by about two hundred millimeters. This ensures the top vegetable soil is excavated and removed.

Ground floor concrete slabs are solid and not suspended like storeys above this level. Preparation starts after the foundations and walls are finished. The sides of the walls are the back filled internally and externally. After this, the ground is leveled and compacted to receive the hardcore base. This hardcore is average three hundred millimeters in depth. Proper compaction and consolidation is done. This is the base for concrete that is formed.

After the ground floor slab hardcore is compacted and leveled, blinding is then put. The blinding can be of quarry dust, lose chipping, sand or murram. Anti termite treatment is then sprayed on this surfaces. Formwork for the concrete is then fixed to edges of the foundation wall. This is the concrete thickness. The thickness of concrete is one hounded to one hundred and fifty milliners. The height from stripped level is three hundred millimeters.

On ground floor concrete, damp proof membranes are laid after blinding. A sheet of one thousand gauge diothene sheet is used for this. Next mesh reinforcement is laid above the sheet. After this concrete is mixed and poured on top. Leveling is done with the formwork height. Mixes for concrete are one part cement, two parts sand and four parts ballast. After casting the concrete is watered for atleast seven days for curing. Walling can then proceed.

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Technorati Tags: cast, concrete, floor, ground, slab, solid