Lafarge Q&amp-As on cement for Technology in Architecture

22.03.2013
 

Q: What is the importance of cement in buildings?

 

Cement is important in buildings since it is the vital ‘glue' to bind stone and sand to form concrete, the world's most widely used building material. Cement mixed purely with sand and water is used to make mortar and plaster.

Q: How has the making and use of cement evolved over the years?

 

Although the first cements were produced in antiquity, the material relies on an extremely sophisticated industrial process. The cement used today was discovered in the 19th century and the basic process is the calcining of limestone (CaCO3) and incorporation of silica, aluminium and iron ore to produce a clinker which is ground up with gypsum into a fine powder.

 

Lafarge began its operation in 1833 and today is the world leader in cement with operations in 49 countries.  The Group operates the world's largest building materials research and development facility in Lyon, France.

 

Cement has evolved from being largely straightforward Ordinary Portland cement to the latest generation of fit-for purpose cements formulated with cementitious extenders such

as fly ash and slag, combined with processing additives to provide specific performance characteristics.

 

Cement's primary use is in concrete which was once considered to be purely a dull

structural medium and today is considered to be the versatile sustainable building material

of choice. It allows the widest range of architectural possibilities both in function and appearance. 

 

Q: What are the regulations and standards for cement?

 

Common cements in South Africa are required to comply with the regulated standard      SANS EN 50197-1, which specifies a number of properties and performance criteria.         The composition and strength are required to be displayed by a manufacturer on the packaging of each cement produced.

 

 

 

Q: What protection does South Africa provide for users of cement?

 

Because of its importance as the key component of concrete used to build our houses, offices, bridges and all other infrastructure, cement falls under the Compulsory Specification Act of South Africa and is regulated by an independent government body called the NRCS, National Regulator for Compulsory Specifications.  NRCS administers technical regulations aimed at protecting human health and safety, and the environment. To protect the public, it is strictly illegal to sell cement without a Letter of Authority number (LOA number) reflected on the bag and delivery notes for bulk cement.

 

Cement quality is important for successful, safe construction work: you should always choose a well-established brand, and not be tempted to save a few Rands, especially through buying an illegal product without an LOA.

 

Q: What makes cement good quality?

 

The production of consistent high quality cement requires the control of the quality of all raw materials and the application of world-class industrial engineering to the cement production process.

 

In addition to ensuring strict compliance with local standards, Lafarge plants are subject to rigorous in-house process quality control procedures. Known as "Usage Quality Testing", the strength development and performance of our cements is continually monitored to ensure they will meet customers' requirements.

 

Cement produced by Lafarge South Africa is also fully supported by the unique technical and laboratory resources of Quality Department Southern Africa (QDSA) at Industria, Gauteng. QDSA operates a comprehensive and highly respected SANAS (South African National Accreditation System) accredited Civil Engineering testing facility in South Africa. Complying with ISO/IEC 17025, the facility has a proud seventeen-year track record of continuous accreditation.

 

Q: What are some of the challenges when it comes to the use of cement?

 

To achieve the required results from cement consistently, it is essential that close attention is paid to the recommended mix proportions for concrete and the addition of water. Adding too much water will have an adverse impact on strength.

 

There are also some simple basic precautions for handling cement that should be observed:

  • Storage: make sure cement bags are stored in a dry place protected from rain and

also damp ground. Ideally, the bags should be stacked in a closed shed on a raised platform

  • Safety: sensible handling precautions should be observed:

-          Always wear protective clothing, boots, gloves and safety glasses

-          Wash cement off skin immediately with water and mild soap

-          Thoroughly rinse any cement in eyes with water and seek medical attention if  

irritation persists

 

Q: How is cement sustainable (eco-friendly, energy efficiency, cost effectiveness)?

 

The manufacture of cement requires a high energy input and releases carbon dioxide - a greenhouse gas. Addressing this, Lafarge South Africa has developed a complete range of innovative cement products formulated mainly with siliceous fly ash, a byproduct of coal-fired power stations, but also including limestone and blast furnace slag additions. The products have reduced carbon footprints, while their innovative formulation provides high quality and performance solutions for the needs of virtually any application.  For example, Lafarge's popular general purpose cement, Buildcrete, releases 50% less greenhouse gas emissions in its manufacture than a traditional ordinary Portland cement and its 32,5R formulation offers significant savings compared with typical general purpose 32,5N cements. 

 

Cement once incorporated in concrete is the key component of a versatile building material with an almost infinite variety of uses. Concrete is environmentally-friendly by virtue of it being a natural material that is produced on or close to site with little energy requirement.  In addition, its durability means low maintenance requirements over a structure's life cycle, while excellent thermal and acoustic properties are ideal for building construction. 

 

Q: How can builders make the most of cement?

 

For a particular application there are often several types of cement that could be used and it is recommended that a builder obtains advice from the local Lafarge representative or hardware store. For example:

  • For general homeowner building projects, it is normally recommended that one good quality general purpose cement is used to minimise wastage e.g. Lafarge Buildcrete 32,5R
  • However, if the project needs to be done quickly such as a driveway, or formwork needs to be hired, then using the higher strength class cement, Lafarge Fastcast 52,5N, can be more economical because you need to use less of it compared with a general purpose cement and the job can be finished quicker and with savings.

(For this reason, Fastcast is extremely popular for use by smaller brick and block making enterprises)

  • For major projects, Lafarge's premium technical cement, Powercrete Plus 42,5R, is commonly used by readymix producers and contractors. It has the unique benefit of allowing the contractor to blend it further on site with an extender such as fly ash to meet specific construction needs
  • To guide specifiers and engineers on the selection of quality cements and concretes for specific applications, Lafarge has produced a convenient Specifier Handbook and launched it in combination with an accredited training programme

 

Q: How creative can one get with cement? What are some of the new/interesting things one can do with cement in construction?

 

The creativity comes from its incorporation in concrete and in recent years technology breakthroughs have revolutionised the performance and potential applications for concrete.

One of the most well-known examples of the use of Lafarge high performance concrete technology in recent years was the elegant Millau Viaduct in France designed by Norman Foster.

 

In South Africa, Lafarge is continually introducing innovative cements and concretes that

are transforming building methods and setting new productivity standards. Examples are:

  • Lafarge developed the first specialised road binder, RoadCem CEM II 32,5N, which has proved to be highly successful
  • For stormwater management, Lafarge Readymix recently introduced the unique permeable concrete, HydromediaTM to the local market
  • AgiliaTM Vertical self-compacting concrete from Lafarge Readymix provided the aesthetic and architectural solution for the façade of Menlyn's stunning Podium building

    ENDS

 


NOTES TO EDITORS: INNOVATION, A STRATEGIC PRIORITY

 

Located in 64 countries with 68, 000 employees, Lafarge is a world leader in building materials, with top ranking positions in its Cement, Aggregates & Concrete businesses. In 2011, Lafarge posted sales of 15.3 billion euros.

Since 2010, the Lafarge Group has been part of the Dow Jones Sustainability World Index, the first global sustainability benchmark, in recognition of its sustainable development actions. With the world's leading building materials research facility, Lafarge places innovation at the heart of its priorities, in order to develop materials to respond to customer needs, but also breakthrough solutions to meet tomorrow's challenges. Lafarge devotes 130 million euros to innovation each year, half of which goes towards research into reducing environmental footprint.

For more information on Lafarge, visit the website www.lafarge.com

 

 

 

 

 

 

 

For further information, please contact:

 

Charlene Lamb

Country Communications Manager

Lafarge South Africa

011-657-1265

Charlene.lamb@lafarge-za.lafarge.com

 

Issued by:

Bridget von Holdt

Inzalo Communication

Tel: 011 646-9992 / 082 6100650

bridget@inzalo.com