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Amol Popli Head Sales (Restofix) STP Limited www.stpltd.com |
The deterioration of reinforced concrete structures is recognized as a major problem worldwide. Today, concrete repair is a major industry supporting the needs of virtually every concrete structure.
Each structure requires routine repair and maintenance, ranging from simple protective coatings to repair of spalling to strengthening of under-designed components. Apart from requiring regular maintenance, many structures require extensive Repair, Rehabilitation & Retrofitting.
Though concrete is quite strong mechanically, it is highly susceptible to deterioration and thus gets damaged & even fail ultimately, unless some measures are adopted to counter deterioration. Such deteriorated structures can be rehabilitated and retrofitted by using various types of modern repair materials and techniques.
STP Limited provides Restofix range of concrete repair materials manufactured to restore and repair damaged or sub-standard concrete by providing structural and non-structural repairs, in addition to sealing and bonding cracks through injections.
Understanding Deterioration And Corrosion
The durability advantage of cement concrete is a major reason why it is the world’s most widely used construction material.But material quality, design and construction practices, and severe exposure conditions can cause concrete to deteriorate, which results in aesthetic, functional or structural problems.
Generally, concrete deterioration is gradual; and, depending on their service and environment, steel-reinforced concrete structures can stand for decades before the onset of steel corrosion. Concrete can deteriorate for a variety of reasons, and concrete damage is often the result of a combination of factors.
Although concrete is porous in nature and the structure contains moisture and oxygen, due to its high alkalinity, the cover concrete surrounding the reinforcements, form a protective, passive oxide layer on the reinforcing steel that reduces the corrosion rate to a negligible level.
For reinforcing steel to corrode, the passive oxide layer on the steel must fail. If the concrete cover that protects the reinforcing steel is damaged and the bond between the concrete and steel reinforcing bar is broken, the steel’s passive layer will break down and active corrosion of the steel will start. There are two mechanisms, however, that will damage the passive layer on the steel reinforcement, even if the concrete cover is not damaged: chloride ions and carbonation. This makes the steel vulnerable to corrosion.
Steps For Concrete Repair And Maintenance
Before commencing any repair work, it is necessary to carry out thorough inspection and evaluation, identify the root cause of the deterioration and accordingly a repair methodology to be prepared and followed. An incomplete or incorrect evaluation may lead to decide on carrying out only surface repairs without addressing the root cause of deterioration. Eventually, the repair work will lead to failure and re-occurrence of the damages.
Accordingly, there are seven basic steps for concrete repair and maintenance:
⦁ Determine the cause(s) of damage
⦁ Evaluate the extent of damage
⦁ Evaluate the need to repair
⦁ Select the repair method and material
⦁ Prepare the existing concrete for repair
⦁ Apply the repair method
⦁ Cure the repair properly
In these steps, the choice of procedure, surface treatment and materials for concrete repair will depend on the existing degree of deterioration, the mechanism of deterioration, its causes and anticipated future service requirements.
Principles And Solutions For Sustainable Concrete Repair
The phases of repair projects follow a logical sequence, which is dominated by engineeringaspects. Depending upon the sequence of repair for a concrete structure, the above Table shows the Product Segments, Product Details, Product Description and Area of Application. The product details mentioned are to address theneed for protection and repair of concrete and to prevent damages due to reinforcement corrosion, respectively.
STP’s Restofix range of products for concrete rehabilitation includes ShaliFix polymer modified structural mortars and micro-concretes designed for replacing the strength of concrete lost due to degradation. The ShaliFix range incorporates active corrosion inhibitors to ensure the integrity of steel reinforcement for many years after repair. Restofix also includes coatings for corrosion protection of steel reinforcements, anti-carbonation coatings for concrete to allow completion protection of structure of the project.
STP’s Restofix range provides ShaliProtek coatings and protection systems and our ShaliWrap carbon and glass fibre and ShaliLam carbon laminates strengthening system.
STP Limited combines these materials to create engineering solutions that repair and extend a structure’s useful life by preventing further damage and to return the structure to original or upgraded service requirements.