Concrete versatility and sustainability important for infrastructural development

Concrete versatility and sustainability important for infrastructural development

Bryan Perrie, managing director of The Concrete Institute

The versatility of concrete boosts the building material’s sustainable merits and should be a decisive factor when maximum quality and longevity are aimed for in infrastructural projects, says Bryan Perrie, managing director of The Concrete Institute (TCI).

Perrie says the user or designer can basically decide what type of concrete he or she needs. “Concrete can be designed and proportioned to meet an extremely wide range of specific requirements including consistencies, flows, setting times, and hardened properties. The product is flexible enough to produce varying strengths at early or late stages, different types of strengths in general, pre-determined densities, as well as the required levels of abrasion resistance and shrinkage.”

When building with concrete, some of the many flexibility benefits include:

  • Concrete can be produced on the building site using a wide variety of transport and placing mechanisms;
  • It can be transported from batch plants to the construction site via a myriad of means ranging from simple wheelbarrows, to heavy engineering vehicles and equipment such as dumpers, trucks, conveyors, cranes and pumps;
  • Concrete can be placed by cranes, pumps, trunks, spraying equipment, and tremies (large metal hoppers and pipes used to place freshly mixed concrete underwater); and
  • Self-compacting concrete (SCC) offers additional flexibility in the placing of concrete and the achievement of excellent off-shutter finishes.

    Versatile concrete in its pre-cast form is used for storm water drainage, water and sewage reticulation pipes

Concrete has the advantage over other materials in that concrete elements such as walls, columns, beams, trusses, and slabs can be constructed in situ as part of the structure being erected, or pre-cast on site on the ground and lifted into their final position via the tilt up and stack casting methods. As a hybrid of pre-cast and in situ concrete, concrete can also be pre-cast kilometres away in a pre-cast yard and transported to site and placed into position there.

An additional benefit is that all of the above options can be combined on one project. This may mean that some elements are constructed in situ, while others may be pre-cast on site and still other pre-cast off-site,” Perrie adds.

Dealing with the versatility of pre-cast concrete, he says this economical construction product is derived by casting concrete into a reusable mould or form which is then cured in a controlled environment, transported to the construction site to be lifted into place as opposed to standard concrete which is poured into site-specific forms and cured on site.

By producing pre-cast concrete in a controlled environment – the so-called ‘pre-cast yard’ – it is possible to monitor and control all stages of production, including ensuring that adequate curing is carried out to ensure that the final products fully comply with strength requirements.”

Pre-cast yards may be established, operational factories or can be created on site. The pre-cast concrete is generally cast at ground level which helps with safety and productivity throughout a project. “As stated, there is greater control of the quality of materials and workmanship in a pre-cast yard than when concrete is cast in situ. Pre-cast yard production tends to lead to increased better durability and when the products and structure last longer, the end-result is cost saving in maintenance, materials and energy – not to mention eliminating inconvenience. The forms used in a pre-cast plant may be reused hundreds to thousands of times before they have to be replaced which ensures that the cost of formwork per unit is lower than for in situ construction.”

Concrete can be pre-cast on site on the ground and lifted into their final position via the tilt up and stack casting methods

Furthermore, if the structure has been appropriately designed, pre-cast products can be removed and reused after the structure has reached the end of its life and is to be replaced.

Perrie says there are many forms of pre-cast concrete products, including:

  • Pre-cast architectural panels used to clad all or part of a building;
  • Storm water drainage, water and sewage reticulation pipes, culverts, manholes, sumps and tunnels;
  • Pre-cast building components used architecturally as cladding, trimmings, accessories and curtain walls;
  • Pre-cast concrete’s structural applications include bricks, blocks, foundations, beams, floors, walls and other similar components; and
  • Pre-cast concrete products are also used in the building, safety and site protection of various transportation systems in the form of culverts, bridge beams and segments, railway sleepers, sound walls or barriers, safety barriers and kerbs.

The increased control of pre-cast concrete in the production phase ensures fewer reject products and consequent saving of raw materials, as well as speeding up construction on site. Well-situated, highly sophisticated pre-cast yards produce pre-cast products to very high tolerances resulting in significant time-savings on site. Examples of this were the pre-cast plants that manufactured the thousands of pre-cast concrete tunnel and bridge segments of the Gautrain infrastructure.”

Perrie adds: “The social contribution of concrete to civilisation cannot be overestimated. It is the second most used resource in the world after water and contributes significantly to human standard of living including the houses we live in, the schools and universities we attend, the offices we work in, the infrastructure of water reticulation and sewers, the dams that hold our water, and the roads that fulfil the needs of mankind globally.”

Concrete Conference unites the industry

AfriSam, main sponsor of The Concrete Conference, staged an impressive exhibit

A united industry is a stronger one that is better able to represent its members through periods of high growth while maintaining its solid structure in times of adversity.

This was the overriding message of The Concrete Conference 2018, which was held in Boksburg recently as the first of its kind to fully involve representative organisations of the concrete and cement industries. The events therefore gave local and international speakers the ability to address a combined audience of members of The Concrete Institute (TCI), Concrete Society of Southern Africa (CSSA), Concrete Manufacturers Association (CMA), Southern Africa Readymix Association (SARMA) and the Association of Cementitious Material Producers (ACMP).

Richard Tomes, Executive: Sales and Marketing, AfriSam opened The Concrete Conference proceedings

In opening the conference, Richard Tomes of AfriSam, the main sponsor, said that a unified industry is essential for the industry to make headway. “The entire construction industry needs to plan for the future and map a way forward that involves all professionals’ bodies within the industry. It is therefore so important that the concrete industry finds its unified voice to help shape construction in future and to address challenges that face this end of the sector.

Strong voice

If we don’t get our act together soon our infrastructure will collapse, and it has already started at some levels within our municipalities and state-owned enterprises. But, in order to make positive changes we need everyone to be on board. We need to support industry associations such as these here today and obtain funding to keep them going.

The Concrete Conference 2018 in Boksburg was the first of its kind to fully involve representative organisations of the concrete and cement industries

For example, AfriSam is the only cement producer that is a member of SARMA right now and, in my opinion, it is just not right that it funds this association by itself. It is time other role players and suppliers to these industries start to contribute. If not, we will also eventually be forced to withdraw our funding and the industry’s own association may be faced with closure as a result. It is time for other role players to step up and support all our concrete professional bodies,” said Tomes.

SARMA’s Johan van Wyk, agreed adding that associations have to move with the times and become more relevant with added benefits for members and a louder voice within policy and economic frameworks. By combining the strengths of the industry bodies, it will be possible to provide more value for members. “What excites us unites us!”

Long road

Adding to the discussion, TCI’s Bryan Perrie, continued saying that the pooled resources of the five associations will make for a robust organisation that will have different agendas for different disciplines, but the same end goal to make concrete the building material of choice.

At present the individual industry bodies draw funding from the same major stakeholders and these cannot continue to fund them as they had in the past. Whereas a single coordinated body is more agile and eliminates duplicated costs, it can still continue to provide the key activities that had previously been provided and more.”

In closing he said that a lot of work still needs to be done to unify the concrete associations and that consultations with members and business studies were still being conducted to work out the finer details.