The concrete protective layer thickness refers to the distance from the outer edge of the outer reinforcement (including stirrups, structural bars, distribution bars, etc.) in the concrete structural member to the concrete surface.
Concrete protective layer repair material
High-strength polymer mortar, suitable for reinforcing engineering of wire rope mesh-polymer mortar overlay structures; applicable to all structures prone to bending, especially for representative bending structures in civil engineering such as reinforced concrete bridge slabs and beams; also suitable for abutment sections, main tower axis parts, and cracking areas on highway cement pavements.
For reinforced and prestressed concrete, the thickness of the concrete protective layer determines the overall service life of the structure. A compliant protective layer ensures durability, corrosion resistance, and the functionality of grip strength. A qualified concrete protective layer not only allows the reinforcement to achieve the designed strength but also ensures fire resistance.
What are the dangers of an inadequate protective layer?
(1) Insufficient thickness of the concrete protective layer can result in inadequate protection for the steel reinforcement, leading to oxidation, rusting, and expansion of the steel. This not only significantly reduces the related mechanical properties but may also cause concrete cracking.
(2) Excessive thickness of the concrete protective layer affects the reinforcement ratio indirectly. The concrete around the steel bars approaches a state of being un-reinforced near the structural outer edge, leading to unsatisfactory tensile properties and the formation of cracks.
How to Reasonably Control the Thickness of the Protective Layer?
1
Macro-control
When pouring concrete, control the amplitude reasonably to avoid disturbing the steel bars and causing displacement.
(2) When vibrating concrete, be cautious to prevent the vibration rod from contacting rebar. It is strictly prohibited to have people walking or stepping on the steel mesh during vibration.
(3) During concrete construction, a rebar worker should be present to continuously inspect for any damage or displacement of the rebar, and promptly correct, repair, or replace as needed.
2
Detail control
Properly select and set up spacers or shims to ensure the thickness of the concrete protective layer.
(2) Install steel support members and apply anti-corrosion treatment to the concrete surface.
(3) Different colored blocks and steel support components are used to differentiate between various sizes for different parts.
(4) Lay down pathways and designated construction access routes to prevent steel bars from being stepped on by construction workers.
The etherized starch has a minimal impact on the bulk density and consistency of freshly mixed expanded perlite mortar. As the dosage increases, the bulk density increases slowly and the consistency decreases slowly, with no significant effect on the air content.

High-strength polymer mortar has strong water retention, excellent anti-slip properties, superior flexibility, good frost-thaw and weather resistance, low water absorption rate, and minimal shrinkage.

The integral concrete structural organization inherently contains potential defects, which manifest as pores in the concrete structure and cracks developing around aggregates before loading, making them weak points in the concrete.