Special Training For Concrete Work In Winter

Special Training For Concrete Work In Winter

Icy weather’s effects on concrete is covered in detail in The Concrete Institute’s SCT30 “Concrete Technology” training – an intensive five-day course that deals with, among many other subjects, the special techniques required for cold weather concreting.

John Roxburgh, senior lecturer at TCI’s School of Concrete Technology, says special techniques required for winter concreting include optimising the mix design, methods of heating up the concrete, thermal curing and the use of concrete maturity measurements.

Dealing with extreme temperature is fundamental to good concrete practice on site. Cold weather concreting is often defined as the placing of concrete at temperatures below 50C and in the South African there are many areas that will have ambient temperatures around or below 50C – especially early in the mornings, late afternoons and evenings.”

John Roxburgh, senior lecturer at the School of Concrete Technology

Roxburgh says in cold weather several potential problems may occur:

  • The binder will hydrate at a slower rate leading to concrete taking longer to set and gain strength which has the knock-on effect of longer bleed times and difficulties in finishing, as well as later stripping times;
  • There is also a chance of the concrete freezing with the associated damaged caused by the expansion of ice within the concrete.
  • Thermal cracking in mass pours may also be harder to prevent with high temperature differentials between the hotter core concrete and the outer concrete in contact with the low external ambient temperatures.

However, there are some basic and simple steps to take for concrete work in cold weather. The first is to always try and cast the concrete on a rising thermometer: rather cast in the early morning with the ambient temperature increasing as this would give the concrete more time to gain strength before it potentially freezes. Try and use slightly ‘richer’ mixes by either adding more cement to the mix or reducing the extender content in the cement. The use wooden formwork to help insulate the concrete or placing industrial insulating blankets and mats over the concrete will also help. The concreting works could also be done in a tent.

Concrete pour at sunset:
Casting concrete early in the morning in winter gives the concrete more time to gain strength before it potentially freezes, says John Roxburgh, senior lecturer at the School of Concrete Technology.

All these measures are reasonably easy to implement and will help tremendously in protecting concrete but there are more sophisticated and integral techniques that can be used in cold weather concreting to prevent costly setbacks – and these are covered in the SCT30 course offered by the School of Concrete Technology,” Roxburgh adds.

The TCI School is the oldest and largest provider of concrete technology education in South Africa and has a wide range of courses that cater for all levels of competency.

For more details about the SCT30 course as well as all the other 2019 courses planned in Midrand, Cape Town and Durban by the School of Concrete Technology this year, phone 011 315 0300 or email sct@theconcreteinstitute.org.za or visit www.theconcreteinstitute.org.za.

Ideal – and essential: Introduction to Concrete

Ideal – and essential: Introduction to Concrete

The Concrete Institute’s School of Concrete Technology will this year again present a basic – but “absolutely essential” – training course in concrete technology for diverse operational levels in the construction sector.

John Roxburgh, senior lecturer at the School of Concrete Technology in Midrand, says the aptly-named two-day Introduction to Concrete course is suitable not only for emerging and new building contractors, small or medium-sized enterprises, but also for any newcomer to concrete-related work responsibilities.

John Roxburgh, senior lecturer at the School of Concrete Technology

For a start, sales and laboratory staff as well as site employees will greatly benefit from the SCT 10 Introduction to Concrete course. The training – augmented by laboratory sessions with hands-on experience – deals with essential elements of concrete operations such as getting the basics right and knowing why certain procedures and practices are required. This is essential background knowledge for anyone planning careers in concrete and concrete-related industries,” Roxburgh states. “In fact, even the most junior staff in companies in the cement and concrete sectors should be armed with the knowledge this course offers.”

He says the increasing number of emerging building contractors now entering the construction industry will also greatly benefit from the Introduction to Concrete training. “Concrete plays a major role on any construction site and needs to be placed and finished off correctly for any contract to be successful and a new company’s reputation to be established. Unfortunately, many newcomers to the construction industry tend to think that making suitable concrete is merely a matter of mixing some sand, stone and water with a bag of cement. There is far more to producing sustainable concrete than such basic knowledge.”

Roxburgh says the Introduction to Concrete course will give emerging contractors and other key players in the construction industry important information to edge out competition. “It is a course that covers all essential aspects such as the basics of materials for concrete, batching and mixing of concrete, and the necessary requirements for transporting, placing, compacting, and protecting as well as curing of concrete.”

Also included in the course are topics such as:

  • Properties of concrete;

  • Receiving and storing materials;

  • Testing of concrete;

  • Finishing and surface preparation;

  • Formwork and reinforcement;

  • Sand-cement mixes; and

  • Durability of concrete.

    The correct method of curing concrete forms part of the training in the School of Concrete Technology’s Introduction to Concrete course

For emerging contractors, an additional benefit is that one of the School of Concrete Technology’s experienced lecturers, Matthews Magwaza, can explain concrete concepts in five South African languages,” Roxburgh adds. “Our total offering for all levels of competency explains why the School has for many decades been the most respected provider of concrete technology education in South Africa.”

More details on the SCT10 course and other more advanced training from the School of Concrete Technology planned for Midrand, Cape Town and Durban this year are contained in the SCT 2019 Education Programme which can be obtained by phoning 011 315 0300 or email sct@theconcreteinstitute.org.za or visiting www.theconcreteinstitute.org.za.

Students: Prepare now for the 2021 Advanced Concrete Technology course

Students: Prepare now for the 2021 Advanced Concrete Technology course

The Zeitz MOCAA Museum of Contemporary Art Africa in Cape Town – the epitome of applied concrete technology Photos: Gareth Griffiths

South African cement and concrete industry professionals should be preparing now to be accepted as 2021 students for the SCT50 Advanced Concrete Technology (ACT) course, a certificate globally accepted as the pinnacle in concrete technology.

This is the advice of John Roxburgh, lecturer at The Concrete Institute’s School of Concrete Technology.

The School of Concrete Technology (SCT) has confirmed that it will again offer tuition for the SCT50 Advanced Concrete Technology (ACT) course in January and February 2021. The School offers this highly prestigious course every two years and enrolment for the 2019 presentation has already closed.

The Advanced Concrete Technology examinations and diploma – presented by the School on behalf of the Institute of Concrete Technology in London – is a challenging course, with examinations covering over 60 topics in concrete technology. So, extensive and intensive preparation is needed simply to start the studies.

Advance preparation

The School of Concrete Technology therefore recommends that in the two year lead-up to the 2021 ACT course, prospective students should enrol for and complete three courses offered by the School: SCT30 Concrete Technology, followed by two important concrete technology and construction courses: SCT41 General Principles and SCT42 Practical Applications.”

Roxburgh says the SCT30 course covers important concrete technology concepts to prepare students for SCT41 and SCT42. “These are essential firm foundations from which attempts at the ACT diploma should be launched. Both provide sound general introduction to most of the topics covered in the ACT. In fact, a prerequisite for being accepted for the SCT50 Advanced Concrete Technology course is a pass in both the SCT41 and SCT42 courses.”

He says it therefore makes sense to use the two years ahead to become fully prepared technologically before the School starts its 2021 Advanced Concrete Technology training.

The School’s broader 2019 Education Programme is now available and contains full details about the above and all other courses to be presented in Midrand, Cape Town and Durban next year. alloescort.ch

For full details, phone 011 315 0300 or email sct@theconcreteinstitute.org.za or visit www.theconcreteinstitute.org.za