Repair Method for Honeycombed and Porous Concrete According to International Standards
Definition
Honeycombed concrete refers to areas where voids, gaps, or cavities are left in the concrete due to inadequate compaction, segregation, or improper placement. Porous concrete exhibits high permeability or has interconnected voids due to insufficient cement paste or improper mix and placement.
Repair Method (According to Standards)
According to *ACI 546R-14: "Guide to Concrete Repair"*, *ACI 562: "Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures"*, and *EN 1504*, the standard repair method for honeycombed and porous concrete includes the following steps:
Assessment and Identification
Conduct a detailed survey to identify the extent and depth of the defective (honeycombed or porous) areas.
Evaluate if the structural integrity is compromised.
Surface Preparation
Remove all loose, weak, or unsound concrete using appropriate methods (chipping with a hammer, hydrodemolition, or other mechanical means) until reaching sound, dense concrete.
Clean the exposed surface thoroughly. All dust, laitance, oil, or contaminants must be removed (using air, water jetting, or vacuum).
Expose reinforcing bars if corrosion is suspected, and clean them to bare metal by wire brushing, sandblasting, or other suitable methods.
Substrate Conditioning
Pre-wet the substrate if a cementitious repair material is used to achieve a Saturated Surface Dry (SSD) condition but without standing water.
For polymer or epoxy-based repairs, ensure the substrate is dry as per the product specifications.
Repair Material Selection
Choose a repair material that is compatible with the existing concrete (grading, thermal expansion, strength, modulus of elasticity).
Select from pre-packaged repair mortars, site-mixed concrete, shrinkage-compensated mortars, or polymer-modified mortars conforming to EN 1504-3 (Structural and Non-structural Repair Mortars).
Application of Repair Material
For shallow repair (less than 40 mm): Use patch repair mortar, applied with a trowel, spatula, or by spraying.
For deeper repair: Formwork may be required, and the repair can be poured or injected.
In special cases, low-viscosity epoxy injections may be used for very fine porous zones if structural performance must be restored.
Curing
Follow manufacturers' recommendations for curing (typically moist curing or curing compounds).
Protect repaired zones from rapid drying, freezing, excessive heat, or impact during the curing period.
Quality Control
Inspect the repair to ensure complete filling of voids and good bonding.
Perform non-destructive testing (NDT) if necessary to confirm the quality and soundness of repairs.
Protection (Optional)
Apply surface sealers or protective coatings (such as waterproof coatings or silane/siloxane) if the structure is exposed to aggressive environments.
References
ACI 546R-14: Guide to Concrete Repair
ACI 562-21: Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures
EN 1504-3: Products and systems for the protection and repair of concrete structures
BS EN 12620: Aggregates for concrete
Professional Solutions
RBS-CONTECH (a brand of Iran Concrete Clinic Group) is specialized in concrete repair and strengthening works, equipped with an expert engineering team, experienced execution teams, and advanced tools, providing tailored solutions according to international standards for all types of concrete defects.
Website: www.clinicbeton.com, www.rbs-contech.com
Email: clinicbeton.com@gmail.com
Phone: +982188070173, +982188584906
Mobile: +989102333497, +989120916271, +989120916272