Classification and Applications of Repair Mortar
Release Time:
2015-07-27
Source:
Classification and Applications of Repair Mortar
Repair mortar primarily refers to polymer-modified, cement-based dry-mix mortar. It is mainly used for repairing concrete defects, as well as for the reinforcement and renovation of aging buildings and bridges, and is the material of choice when the thickness of damage to the concrete surface layer is less than 50 millimeters. Repair mortar has properties similar to those of the deteriorated existing concrete, exhibiting excellent compatibility and outstanding bond strength, while meeting the requirements of repair projects for compressive strength, flexural strength, wear resistance, flexibility, and low shrinkage. It also features convenient application, good workability, excellent slump retention, and ease of placement on vertical and overhead surfaces; moreover, once cured, it offers an attractive appearance and superior durability. So, how is repair mortar classified? Generally speaking, it is divided into two main categories: mortars for exterior finishing and decorative repairs, and mortars for aesthetic restoration. Cement-based mortars are used for both interior and exterior finishes, whereas gypsum-based dry mortars are employed only for certain specialized interior applications (aesthetic restoration), such as filling small holes, voids, cracks, and cavities to restore their original dimensions. As for structural repair mortars, based on the sequence of construction, they can be further categorized into primer mortar, intermediate-layer repair mortar, and fine-layer repair mortar.
(1) Primer
It is primarily composed of cement and contains a small amount of redispersible latex powder. This primer mortar is alkaline, providing protection to the reinforcing steel while the resin content ensures strong adhesion to both the reinforcement and the substrate.
(2) Middle layer
It provides excellent crack resistance and filling performance, while possessing sufficient strength to form an integrated, robust load-bearing system.
(3) Surface Layer
Concrete repair areas are typically covered with a fine decorative finish, which smooths the rough concrete surface and renders it pore-free. The repair material must exhibit adequate bond strength, a smooth surface, good workability, sufficient hydrophobicity, and appropriate vapor permeability, thereby ensuring complete drying and effective protection of the substrate.
Repair mortar can be used not only for exterior plastering and repair of reinforced concrete structures or cracked building surfaces, panels, load-bearing columns, beams, and other structural elements in both industrial and civil facilities, as well as for exterior decorative finishes in damp industrial and civil buildings, but also for repairing defects such as honeycombing and voids in concrete, thin-layer repairs of damaged concrete floors, and the application of a comprehensive protective overlay on concrete, masonry, or steel structures. It is also highly effective for the rehabilitation of damaged industrial and civil buildings that no longer meet design requirements.
