TECHNOLOGY
Maintaining concrete strength
Comment contributed by a. b. e.
While admixtures can add strength, the durability of concrete structures can be greatly increased by a proper preventative maintenance and repair programme.
Images by a. b. e.
Products produced by a. b. e. are being used for maintenance work on several N14 highway bridges between the Hartbeespoort / Sandton and Lanseria off-ramps.
Warren Trew, Gauteng sales manager: General Construction of a. b. e. Construction Chemicals, says that the durability of concrete depends largely on undertaking proper preventative maintenance. He points out that many key South African building and civil structures have eroded with age, neglect, misuse, weather factors, rebar corrosion, extraneous loading, and natural disasters.“ Neglecting the need to introduce proper repair and maintenance systems for these structures results in reduced capital value and wastage of resources, which could lead to poor quality of life for communities. With large parts of South Africa currently experiencing devastating drought, the need for adequate maintenance of water reservoirs and dams particularly comes to mind.“ In a sustainable built environment, structural maintenance is nonnegotiable. As soon as a concrete structure is completed, the need for a maintenance programme must start. Maintenance should not be driven simply by the need to correct defects that occur over time, but to avoid these defects in good time,” Trew states. He says concrete is a durable but not eternal material and will over time deteriorate and require repair or replacement, especially in zones where chloride ingress or carbonation are a reality. Repairing deteriorated concrete and restoring its structural integrity should consequently form part of the initial design— but are frequently resorted to only when emergencies arise.
“ The first step in a successful repair project involves early damage assessment and arriving at a proper diagnosis. The owners should not wait until the concrete shows obvious signs of distress. The most crucial aspect of the repair process is the evaluation stage. To properly repair any damage, it is important to understand what caused the problem and then determine the correct method of repair.“ Experience is vital for the diagnosing and planning for concrete repairs. While there is a high level of expertise that goes into concrete construction, the skills, understanding, and experience required to repair damaged or deteriorated structures are decidedly different from those required to build new structures. That is why it is important to consult reputable suppliers of concrete repair products
24- CEC April 2018