Product Overview

MC-Dur 300 is a factory-premixed, polymer-modified cementitious repair mortar from MC-Bauchemie covering the medium-grade structural repair range for reinforced concrete — the product sits between the fine skim coat finishing range (MC-Dur 100) and the high-build coarse aggregate range (MC-RocTec HB) and addresses the most common repair depth encountered in structural concrete restoration practice: 10 to 40 mm per layer, with multiple layers applicable for greater depths. The classification of MC-Dur 300 as EN 1504-3 Class R3 defines its performance requirements: compressive strength minimum 25 MPa at 28 days; flexural strength minimum 4 MPa; chloride ion content maximum 0.05 percent; carbonation depth no greater than the comparison mortar; compatibility with the substrate concrete in terms of modulus of elasticity and thermal expansion; adhesion bond minimum 1.5 MPa pull-off strength; and shrinkage resistance within the EN 1504-3 envelope. The polymer modification (typically a redispersible polymer powder incorporated during factory manufacture, SBR or modified EVA type) serves multiple functions: it improves the adhesion bond between the fresh mortar and the existing concrete substrate; it reduces the water-cement ratio achievable at a given workability, improving density and reducing permeability; it provides a degree of crack accommodation (microductility) preventing the repair mortar from cracking and delaminating during the early shrinkage phase; and it improves the freeze-thaw resistance of the cured mortar. The application range of MC-Dur 300 covers: spalling repair on soffits of bridge and building beams where corroded rebar has caused delamination of the concrete cover; repair of deteriorated columns and walls in industrial buildings subject to carbonation-induced and chloride-induced corrosion; repair of construction defects (formwork blowholes, segregation zones, cold joints); repair of fire-damaged concrete where the heat has reduced the surface concrete to low strength; and repair of concrete elements suffering from alkali-silica reaction (ASR) cracking and surface deterioration. Space Arc Engineering supplies MC-Dur 300 for structural concrete repair contractors, consulting engineers, and infrastructure maintenance agencies across Ghaziabad, Delhi NCR, Noida, and Uttar Pradesh.

Applications

• Bridge beam soffit repair — hand-applying MC-Dur 300 to the soffits of pre-stressed and reinforced concrete bridge beams on NH and state highways where carbonation or chloride penetration has caused rebar corrosion, concrete cover delamination, and spalling — soffit repair is the most common structural concrete repair category on the Indian road network and MC-Dur 300 provides the 10 to 40 mm depth repair capability required for typical cover zone restoration
• Column and pier capital repair — reinstating deteriorated concrete on the columns and pier capitals of flyovers, metro viaducts, and industrial buildings where corrosion-induced spalling has reduced the section geometry and exposed the rebar to further atmospheric attack — hand application of MC-Dur 300 allows careful restoration of complex section profiles including chamfered and curved column corners
• Retaining wall face repair — repairing the face of deteriorated reinforced concrete retaining walls on highways, railway embankments, and building basements where surface deterioration, cracking, and spalling requires mortar reinstatement to restore the protective concrete cover over the rebar and prevent further ingress of carbonation and chloride
• Construction defect rectification — filling blowholes, segregation zones, honeycombing, and cold joint defects identified after formwork striking on freshly constructed reinforced concrete elements — MC-Dur 300 provides the structural strength, adhesion, and durability required to reinstate construction defects without compromising the structural integrity or durability of the element
• Industrial building structural repair — repairing deteriorated reinforced concrete frames, slabs, and walls in factory buildings, warehouses, and industrial sheds where aggressive process environments (chemical fumes, thermal cycling, vibration) have accelerated concrete deterioration and rebar corrosion to the point requiring structural intervention
• Fire-damaged concrete reinstatement — restoring the cross-section of reinforced concrete elements (columns, beams, slabs) that have suffered surface concrete loss due to fire exposure, where the heat has reduced the concrete compressive strength and caused surface spalling — MC-Dur 300 is applied after removal of all fire-damaged concrete back to sound substrate

Key Advantages

• EN 1504-3 Class R3 compliance — verified structural repair performance to the most widely specified European standard for concrete repair mortars — gives engineer and owner confidence in consistent, documented performance beyond locally manufactured repair mortars of uncertain quality
• Polymer modification for superior adhesion — redispersible polymer powder incorporated at factory provides minimum 1.5 MPa pull-off adhesion bond to prepared concrete substrate — adhesion failure (delamination) is the most common cause of repair failure in Indian climatic conditions and MC-Dur 300 specification eliminates this risk
• 10 to 40 mm per layer application range — covers the full depth range of typical structural concrete repair without requiring aggregate grade changes — reduces the number of products a repair contractor needs to stock and allows flexibility in repair layer sequencing on site
• Factory-premixed quality assurance — no site batching variability — every bag produces mortar of consistent composition and performance — eliminates the quality variation endemic in site-mixed cement-sand-polymer repair mortars and provides a reproducible, verifiable repair specification
• Low shrinkage — polymer modification and optimised cementitious formulation reduce drying shrinkage to within EN 1504-3 limits — low shrinkage prevents repair delamination and surface cracking at early age, the most common field failure mode for repair mortars applied in the high-evaporation summer conditions of Delhi NCR (May-June)
• Compatible with corrosion protection systems — MC-Dur 300 is compatible with reinforcement corrosion protection coatings (MC-Dur coating range) applied to exposed rebar before mortar application — provides a complete, integrated repair system from rebar treatment through to mortar reinstatement and surface finish