From Past to Present

Modern Construction Materials

When the subject of construction materials is raised, traditional products immediately come to mind. Many raw materials, like wood and stone, have been used in building for thousands of years, and remain popular today for a number of reasons ranging from necessity to cost, convenience, and availability…
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Times change, and many of the resources we took for granted, such as forests which covered considerable land masses a century ago, are quickly disappearing, making quality wood used for construction harder to obtain. Other time-tested materials, such as concrete – a mixture of cement, water, and coarse aggregates – have contained everything from horse hair to blood and volcanic rock and ash over the centuries.

Like any building material, wood, stone and concrete have their advantages and disadvantages. While still relatively cheap, wood is prone to insect activities, rot, fire, and shifting over time, leaving what were once perfectly level floors and doorways distorted. Concrete, highly durable, is still vulnerable to moisture, especially in colder climates where salt is used in winter, which melts and seeps into concrete floors and can cause putting, cracking, flaking, and chips, and can corrode rebar, causing further damage.

Innovations in concrete
To keep up with demand from the construction sector, new products continue to be created which are lighter, more durable, more cost-effective, longer-lasting, and often easier to use. As buildings from high-rise apartments to industrial and manufacturing facilities grow larger, the need for durable materials increases. In the concrete sector, these materials include a wide range of products, including Self-Compacting Concrete (SCC), High-Performance Concrete (HPC), Ultra-High Performance Concrete (UHPC), Durable Concrete, and others. Representing one of the major costs associated with construction, concrete must be exceptionally durable and structurally sound, otherwise buildings and infrastructure such as bridges will require costly repairs.

Products such as Ultra-High Performance Concrete have extremely high durability, with flexural strengths up to 7,000 pounds per square inch (PSI), and compressive strengths of up to 29,000 psi. Used on structures including concrete train station canopies and bridges, UHPC’s properties and flexibility enable it to accommodate architectural designs such as large curved spaces, while remaining extremely durable against corrosion and even impact, resulting in a significantly increased lifespan and less maintenance.

Other concrete products, such as Self-Compacting Concrete – also known as Self-Consolidating Concrete – are extremely fluid, do not require tamping or vibration following pouring, and are nearly self-levelling. As a result, SCC, when compared to standard concrete, requires less labour. Originating in Japan in the mid-eighties, SCC is credited with helping the world of architecture because it conforms to unusual shapes, and is now widely used worldwide.

Like concrete, steel remains widely used in the construction industry, due to its structural strength and flexibility. Depending on the size and scope of the project, hot rolled steel is used more frequently for large infrastructure works, while cold formed steel is widely used for residential and other smaller jobs. Unlike wood, steel is insect and rodent-proof, recyclable, and does not combust.

Inside, looking out
Just as there have been numerous developments with the internal structures of buildings, new products have made their way onto building exteriors. Widely known as Exterior Insulation and Finish Systems (EIFS), these systems serve a number of practical and aesthetic purposes. Non-load bearing, these exterior wall cladding systems – sometimes referred to as External Thermal Insulation Cladding Systems (ETICS) – consist of insulation board attached to substrates with strong adhesives or mechanics. First used in Germany to reface damaged masonry walls following the Second World War, and entering the American marketplace in the sixties for commercial structures, EIFS’s have steadily evolved, becoming lighter, more durable, and increasingly efficient.

Sold under different brand names, EIFS’s are required to meet specific standards. While some early systems had issues with moisture penetration, particularly from rain, drainage systems are now used to allow water to flow out from behind the cladding and not remain trapped, where damage can occur. Widely used in commercial and residential applications today, EIFS’s have outperformed other surfaces such as stucco, brick, and fibreboard siding in terms of moisture and thermal control, and – when properly installed – actually save construction costs, result in increased energy savings, and have less of a detrimental impact on the environment compared to other exterior cladding products.

Wood-plastic composites
Growing in popularity in recent years are wood-plastic composites (WPCs), made from 30 to 65 per cent real wood, such as sawdust, straw, or even bamboo mixed with plastic fibres, usually polyethylene (PE). Mixed together with other materials, colours, lubricants and chemical additives depending on the product’s ultimate use, all wood-based ingredients are precisely dried to remove moisture, and ground very finely to mix with plastic particles. Once thoroughly mixed, technicians determine the appropriate consistency, and the material is then extruded or moulded into a variety of shapes, thicknesses, and dimensions.

Unlike real wood, which is prone to termites and water damage, WPCs result in products such as floor or deck boards which require little, if any, maintenance other than cleaning. And unlike genuine wood, these composites can be manufactured to have a rigid core and veneer made from vinyl. Initially introduced in the 1990s and used for outdoor decks, these composites are now made into boards or shaped into pieces used for moulding, trim, window and door frames, railing, fences, cladding, timbers for landscaping, and other uses.

Like every other construction material, WPCs have their advantages and disadvantages. While highly resistant to rot and insects, boards made from these composites are less stiff and not as strong as real wood. And although WPCs don’t hold as much moisture as wood, they still absorb moisture, and can be affected during periods of extreme heat or cold. Since they contain polymer, these products are affected by the sun’s ultraviolet rays, and can fade over time. The weight of WPC is heavier than similar-sized pieces of genuine wood and, although new uses are being developed, remain best suited to applications where weight is not an issue, such as outdoor decks for single-family housing construction.

From the very framework of a structure to the exterior fulfilling the vision of architects and designers, construction products continue to evolve and become lighter, more durable, and longer-lasting than ever before. And while traditional materials like wood, stone, cold-formed and hot-rolled steel, brick, and concrete will continue to be widely used, these tried-and-true building products will continue to evolve to meet the building needs of tomorrow with an eye on speed of construction, safety, and respect for the environment.

Home Automation

Call it ‘domotics,’ and you are likely to receive a blank stare, but refer to it as ‘smart home’ or ‘home automation,’ and you will get a nod of acknowledgement. For the past few years, consumers have heard the word ‘smart’ attached to countless products and services, from food and drink to snacks like popcorn and mobile phones, which no one seems to refer to as a ‘cellphone’ anymore. Yet what, exactly, constitutes ‘smart’?

September 24, 2017, 4:45 PM AEST

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2017-09-22 16:10