How to use concrete mortar interface treatment agent correctly?

The correct use of concrete mortar interface treatment agent requires following the four step process of "substrate pretreatment → product preparation → standardized construction → subsequent connection". The key is to ensure that the substrate is clean, the construction is uniform, and the timing is suitable, in order to maximize the interface bonding effect and avoid hollowing and peeling problems.

1、 Step 1: Substrate pretreatment (determining the bonding foundation, the most critical step)

The bonding effect of the interface agent depends on the surface state of the substrate, and the following issues need to be thoroughly addressed:

Clean the surface

Remove floating ash, loose sand particles, oil stains, release agents, old coating layers, etc. on the surface of the substrate (new and old concrete, walls, etc.), which can be polished with a wire brush, sandpaper, or washed with a high-pressure water gun (construction after drying);

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If there are cracks (width>0.3mm) or holes in the substrate, it is necessary to fill them flat with repair mortar first to avoid the formation of hollows after the interface agent infiltrates.

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Adjust the humidity of the substrate

Dry the substrate (such as old concrete exposed for a long time or newly poured concrete for more than 24 hours): Water it 1-2 hours before construction to ensure that there is no water accumulation on the surface but sufficient moisture is absorbed inside (to prevent the substrate from quickly absorbing moisture from the interface agent, which may cause poor curing);

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Wet substrates (such as underground walls, freshly washed surfaces): Use a cloth to dry the accumulated water on the surface to avoid diluting the interface agent and affecting its strength.

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Processing special substrates

Smooth substrates (such as smooth concrete slabs, prefabricated components): Use sandpaper or angle grinder to polish, forming a slightly rough surface (increasing physical anchoring points);

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Metal substrates (such as steel structure column bases): Rust and oil stains need to be removed, and if necessary, anti rust primer should be applied first, followed by epoxy type interface agent.

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Second step: product preparation (operation according to the type to avoid wrong ratio) force).

Powder type (such as cement-based modified interface agent)

Strictly follow the product manual to mix water (usually water to material ratio 1:4~1:5), stir with an electric mixer for 2-3 minutes until there are no lumps and it becomes a uniform paste. After standing for 5 minutes, stir again (to fully dissolve the ingredients and avoid later shrinkage).

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Paste type/two-component (such as epoxy type interface agent)

The two-component should be mixed in proportion (such as A component: B component=10:1), stirred until the color is uniform (no stripes), and used up within the "shelf life" (epoxy type usually takes 30-60 minutes, and curing failure will occur if exceeded).

Step 3: Standardized construction (control thickness, uniformity, ensure penetration/coverage)

Choose the brushing, scraping or spraying method according to the type of interface agent, with the core being "uniform and leak free":

Brushing/spraying (applicable to liquid type and single component penetration type)

Use a brush, roller or low-pressure spray gun to evenly brush 1-2 times in the same direction. After the first coat dries (non stick to the touch, about 30-1 hour), apply the second coat;

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Thickness control: single pass thickness of 0.1-0.2mm, total thickness not exceeding 0.5mm (too thick is prone to peeling, too thin cannot form effective adhesive film);

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Key points: Additional coating is required at corners and gaps to avoid missing coating (these areas are prone to hollowing due to insufficient bonding).

Scraping (suitable for powder and paste types)

Use a scraper to evenly scrape the interface agent onto the surface of the substrate, with a thickness of 1-3mm (according to product requirements, cement-based materials are usually 1.5-2mm). After scraping, use a scraper to flatten the surface to ensure that it is flat and free of protrusions;

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Attention: Avoid repeated crushing during scraping (to prevent the introduction of bubbles). If bubbles appear, they should be punctured and scraped in a timely manner.

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Step 4: Follow up process connection (grasp the "window period" to avoid failure); Cement based/paste type: Plastering or pouring can be carried out 1-2 hours after construction (initial setting on the surface, with hardness but not sticky to the touch). If the interval exceeds 4 hours, the surface of the interface agent needs to be moistened with water before construction; Epoxy type: Construction is completed within 30 minutes after mixing, and if subsequent bonding is required after curing (usually 24 hours), the surface of the interface agent needs to be lightly polished to increase roughness.

Fifth, Key Precautions (Key Points for Avoiding Pits)

Environmental Control: Construction temperature of 5 ℃ -35 ℃, insulation is required below 5 ℃ (such as covering with insulation film), and shading and watering are required above 35 ℃ (to prevent rapid evaporation of moisture);

; Avoid construction in rainy or high humidity (>85%) environments (affecting curing).

Mixing prohibited: Different types of interface agents cannot be mixed (such as cement-based and epoxy type), and must be matched with the material of the subsequent mortar/concrete (such as epoxy type interface agents being preferred in humid environments).

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Tool cleaning: After construction, promptly clean the brush, scraper (water-based interface agent) or special solvent (epoxy type) with clean water to avoid the tool being unusable after curing.

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