Honeycombing, blowholes & voids

The work, step by step

General guidance based on the manufacturer data sheets. Site conditions differ: confirm the system with MCT before you start. Where we do not name a product, ask us and we will confirm the right one.

1. 1

   Step 1: Assess the depth

   Tap and open up the area. Surface pores and blowholes are a finishing repair. Deep pockets, exposed steel or voids in columns, beams and slabs need an engineer's assessment; repairs follow EN 1504-10 (MonoTop-620 p.2).

2. 2

   Step 2: Cut back and prepare

   Remove weak and deteriorated concrete to a sound base and clean any exposed steel (MonoTop-620 p.3). Pre-wet about 2 hours before, then remove excess water so the surface is dark matt with no water in the pores (MonoTop-620 p.3).

3. 3

   Step 3: Fill pores and shallow honeycombing

   SikaRep Fine PK fills honeycombing and pores, 1–5 mm in one layer (SikaRep Fine PK p.1, p.2). MonoTop-620 repairs minor defects and needs no bonding primer on well-prepared concrete (MonoTop-620 p.1, p.3). SikaTop-121 fills blowholes and fine honeycombing, 2–5 mm (SikaTop-121 p.1, p.2). Sikagard-720 EpoCem fills pores 0.5–3 mm where chemical or moisture resistance is needed; professionals only (Sikagard-720 EpoCem p.1, p.3).

   SikaRep Fine PK Sika

   SikaRep® Fine PK can be used as a: Pore sealer / finishing mortar on cementitious substrates, Thin layer rendering on horizontal and vertical areas in building and civil engineering construction, for external and internal finishing etc, Levelling mortar on uneven substrates, and profiled concrete… (TDS p.1)

   Sika MonoTop-620 Sika

   Sika MonoTop®-620 can be applied with or withour a reinforcement matt, over concrete or mortar surfaces or over SikaTop® or Sika Monotop® mortars. It is suitable for the following uses: Use as a concrete/ mortar pore sealler or levelling mortar, Thin layer render over vertical or horizontal struc… (TDS p.1)

   SikaTop-121 Sika Request a quotation

   Thin layer render Levelling of surfaces Protective coating for bridges parapets, retaining walls, etc. (TDS p.1)

   Sikagard-720 EpoCem Sika Professionals only

   Thin layer render Concrete pore filler/ levelling mortar Repairing minor defects (pores and honeycombed concrete) Protecting concrete in aggressive and chemical environments As a Temporary Moisture Barrier (TMB) for Sikafloor® or Sikagard resin products Sui… (TDS p.1)

   Temperature stated in TDS

   -30 °C min. / +80 °C max (TDS p.2)

   Pack

   Pre-batched 21 kg sets.

4. 4

   Step 4: Repair deeper pockets

   Where steel is exposed, coat it with MonoTop-610, two coats (MonoTop-610 p.3). Rebuild with SikaRep PK or MonoTop-612 PK, up to 30 mm per layer, in several layers for more depth (SikaRep PK p.2; MonoTop-612 PK p.2).

   Sika MonoTop-610 Sika Professionals only

   Bonding primer as part of a concrete repair system Reinforcement corrosion protection as part of a concrete repair system (TDS p.1)

   SikaRep PK Sika

   Repair of spalling and damaged concrete in buildings, bridges, infrastructure and superstructure works. (TDS p.1)

   Temperature stated in TDS

   +5 °C min / +35 °C max (TDS p.2)

   Pack

   25 kg Bag

   Sika MonoTop-612 PK Sika

   Sika MonoTop®-612 PK is used for structural concrete repairs as well as general patching to concrete and mortars. (TDS p.1)

5. 5

   Step 5: Recast large defects

   Cut out to a regular shape, fix secure, watertight formwork and pour a flowable non-shrink material: SikaGrout-114 PK for cavities and gaps, 10–50 mm per pour (SikaGrout-114 PK p.2) or Sikacrete-114 PK micro-concrete at 50–500 mm per pour (Sikacrete-114 PK p.1, p.2).

   Sikacrete-114 PK Sika

   Sikacrete®-114 PK is used for the structural repair of deteriorated concrete. (TDS p.1)

   Temperature stated in TDS

   +5 °C min. / +35 °C max (TDS p.2)

   Other options for this stepAsk us

   The right product here depends on your site. We confirm it before naming it.

6. 6

   Step 6: Inject hidden voids

   Voids that cannot be opened up can be filled by injection: Sikadur-52 LP epoxy fills and seals voids and cracks (Sikadur-52 LP p.1); Sika InjectoCem-190 microcement grout fills voids and protects embedded steel (InjectoCem-190 p.1). Injection is specialist work.

   Sikadur-52 LP Sika Request a quotation

   Injection resin with good adhesion to concrete, mortar, stone, steel, and wood. (TDS p.1)

   Temperature stated in TDS

   +25 °C min. / +40 °C max (TDS p.2)

   Sika InjectoCem-190 Sika Request a quotation

   Injection of Sika® Injectoflex® Systems Typ DI-1 and SikaFuko® injection hoses Filling of voids Final, rigid, cementitious sealing of cracks while simultaneously treating corroding or corrosion-prone reinforcing steel in concrete and mortar (TDS p.1)

7. 7

   Step 7: Cure and finish

   Protect fresh mortar from drying with polythene or a moist membrane (MonoTop-620 p.3). In hot, dry weather fog lightly for 48 hours after final set (SikaRep Fine PK p.2). Coat if required, as in the protective-coatings guide.

Steps and product facts are taken from the manufacturer data sheets (page cited). Products are named only where the data sheet confirms the use; quantities follow a site visit or photos. General guidance: check the data sheet or ask us before you start.