About Sika Sikacrete-145 IN

Sikacrete-145 IN sits in the family of flowable repair micro-concretes that engineers reach for when a damaged section is too deep, too congested, or too load-critical for a hand-applied mortar. It arrives as a grey powder in 30 kg bags, pre-blended by Sika from Portland cement, graded fillers and aggregates, and performance additives. On site you add only clean water, and for thicker sections you can extend it with graded 10 mm aggregate. The result pours like concrete, compacts under its own weight, and cures into a dense, low-porosity matrix that carries load alongside the original structure.

What makes it a specifier’s default for deep repair is the combination of flow and controlled expansion. Because it is self-compacting, it fills the awkward zones behind heavily reinforced columns and beams where a poker vibrator simply cannot reach. Because it expands 1 to 4 percent in the unrestrained state rather than shrinking back, it keeps positive contact against the substrate and the steel as it sets. It is iron-free and chloride-free, so it does nothing to accelerate corrosion of the reinforcement it is meant to protect. For our clients rehabilitating bridges, water structures, and industrial frames, that translates into a repair that behaves like monolithic concrete rather than a patch.

The technical insight

The performance rests on three linked mechanisms. First, a carefully graded particle skeleton (maximum grain size 2.36 mm) plus flow-modifying additives lets the mix stay cohesive yet self-levelling at a low water:powder ratio of just 0.14-0.16 by weight; keeping water low is what delivers a dense, low-porosity matrix and the ~50 N/mm2 28-day strength (ASTM C109), without the bleeding or segregation that plagues over-watered site concrete. Second, a gas-generating expansion system produces 1-4 percent unrestrained expansion (ASTM C827) during the plastic phase, so instead of pulling away from the substrate as ordinary concrete shrinks, the fresh micro-concrete pushes outward and locks into the prepared surface and the steel it encases. Third, the mix is formulated iron- and chloride-free, removing two ingredients that would otherwise set up a corrosion cell around the very reinforcement the repair is protecting. Together these give a repair that develops early strength fast (~15 N/mm2 in a day), bonds tightly (tensile adhesion greater than or equal to 2 N/mm2 per EN 1542), and behaves structurally as an extension of the parent element.

Where it is used

• Deep structural repair of columns, beams, and slabs where damage exceeds patch-repair depth
• Column and beam jacketing to enlarge sections and restore or increase load capacity
• Bridge pier, abutment, and culvert rehabilitation on highways and infrastructure
• Repair of wharves, jetties, and other marine or splash-zone reinforced concrete
• Rehabilitation of dams, reservoirs, sewerage, and water-treatment structures
• Repair of congested, heavily reinforced sections where poker vibration is impractical
• Encasement and build-up around exposed, corroded reinforcement after cleaning and priming
• Structural strengthening of existing frames by section enlargement

Key advantages

• Self-compacting and free-flowing, so it consolidates around dense steel with no vibration
• Non-shrink with 1-4% unrestrained expansion, holding tight contact with the substrate
• Reaches ~50 N/mm2 at 28 days with fast early gain (~15 N/mm2 at 1 day) for quicker formwork cycles
• Iron- and chloride-free, so it will not promote corrosion of the embedded reinforcement
• Factory-blended for consistent, repeatable quality batch to batch
• Can be extended with graded 10 mm aggregate for thicker pours, improving economy on deep sections
• Pumpable over large areas, suiting jacketing and continuous placements
• Dense, low-porosity finish that improves durability and resistance to ingress

Limitations & considerations

• Requires watertight, well-braced formwork; it is a pourable material, not a trowel-applied mortar
• Short working window of about 20 minutes pot life, so only mix what can be placed in time
• Layer thickness is capped at 100 mm per pour unless graded aggregate is added
• Substrate must be mechanically prepared, saturated surface-dry, and reinforcement primed against corrosion for the bond to perform
• Sensitive to hot and cold weather; water and material temperature must be managed to control set and cracking
• Needs disciplined moist curing for a minimum of 7 days to achieve stated strengths

Selection & best practice

Specifications

Industry use cases

How we position Sika Sikacrete-145 IN

Within the Sika repair system, Sikacrete-145 IN is the deep-pour, structural workhorse. For shallower hand-applied patches, pair it with a Sika MonoTop repair mortar rather than forcing a flowable material into thin sections. Reinforcement should be primed with SikaTop Armatec-108 Plus or Armatec-110 EpoCem, large or dense substrates benefit from a Sikadur-32 LP IN bonding coat, and exposed faces are cured with Sika Antisol. Where a client already specifies Fosroc across a project, its Renderoc RG is the natural equivalent from that brand family; and for pure grouting of base plates or pockets rather than section repair, look to a dedicated non-shrink grout such as SikaGrout instead of a micro-concrete.

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