Dr. Fixit Inject AC 300-HP
A hydrophilic acrylate gel injected through packers or a reinjectable hose to shut down hairline cracks and seepage in concrete, with the rare ability to be re-triggered months later without a fresh drill-and-inject cycle.
What is it?
A polyacrylate-based hydrophilic gel supplied as a 4-part kit, acrylic emulsion, accelerator, catalyst and mixing water, pumped into concrete through drilled packers or a pre-cast reinjectable hose (Dr. Fixit Inject RI).
Where is it used?
Diaphragm walls, basement raft slabs, precast segment joints, metro and subway station boxes, water-retaining structures, and any RCC member weeping through micro-cracks rather than gushing.
Why use it?
On contact with moisture the gel swells and locks the crack path shut, and because it can be pumped again through the same embedded hose whenever a joint reopens, it turns a one-time repair into a maintainable system.
How is it applied?
Drill and seat packers, or embed the reinjectable hose before casting, mix Part A (emulsion plus accelerator) and Part B (catalyst plus water) separately, then combine them 1:1 only at the gun tip using a plural-component injection pump.
About Dr. Fixit Inject AC 300-HP
Space Arc stocks Dr. Fixit Inject AC 300-HP for the jobs where a surface coating or a crystalline admixture simply cannot reach: a hairline crack running through a diaphragm wall, a construction joint in a basement raft that has started weeping after the monsoon, or a precast segment joint on a metro box that needs treating without breaking the structure open. It is a polyacrylate hydrophilic gel, not a cementitious slurry or an epoxy, so it stays flexible, tolerates minor structural movement, and reacts fast enough to chase water out of a crack before it finds a new path around the injection point.
What sets it apart from a straightforward two-part epoxy or PU resin is the four-component design: the acrylic emulsion and accelerator go in as Component A, the catalyst is site-mixed with potable water as Component B, and the two only meet at the nozzle tip, giving applicators real control over gel time, anywhere from 1 to 12 minutes, by adjusting the catalyst dose. That range matters on site, because groundwater with a high mineral content can accelerate the reaction on its own, and Pidilite is explicit that a small field trial to fix the gel time is not optional, it is part of the method statement.
The technical insight
The numbers on the data sheet point to a system built for penetration, not bulk fill: Brookfield viscosity under 5 cP is thinner than most epoxy injection resins, which is what lets it travel through pores and hairline cracks a PU foam would bridge over rather than enter. A neutral pH of 7 to 9 (IS 9103) means it will not attack the passivation layer on nearby rebar the way some highly alkaline or acidic accelerators can, and a Shore 00 hardness above 50 keeps the cured gel soft and rubbery rather than glassy, so it can absorb the small seasonal movement most joints see without cracking back open.
Where it is used
- Sealing hairline cracks and joints in cast-in-situ diaphragm and retaining walls
- Basement raft slab and wall construction joints showing dampness after backfilling
- Precast segment and box culvert joints on metro, subway and utility tunnel projects
- Water-retaining structures (STP/WTP tanks, reservoirs) with slow seepage, not active flow
- Underground parking and podium slab cracks with limited surface coating access
- Waterstop backup treatment at expansion and movement joints below grade
- Micro-crack injection ahead of a membrane, so the substrate stops feeding moisture back through
- Retrofit dampness treatment via embedded reinjectable hose for future re-injection
Key advantages
- Non-hazardous and easy to inject, no special PPE beyond standard site practice
- Ultra-low viscosity (under 5 cP) penetrates micro-pores and hairline cracks thicker resins bridge over
- Gel time adjustable from 1 to 12 minutes, tunable to site water pressure and penetration depth needed
- Reversible, hydrophilic swelling lets the seal reactivate if the crack lets water back in
- Works with Dr. Fixit’s reinjectable hose system, so a joint can be re-treated years later without fresh drilling
- Neutral pH (7 to 9) is gentler on embedded reinforcement than strongly alkaline or acidic grouts
- Fast gelling limits water damage to finishes while injection is underway
- Backed by Pidilite’s pan-India technical support and Space Arc’s trained injection crews
Limitations & considerations
- Not for active or gushing water leaks, Pidilite’s own data sheet rules this out; that job needs a water-reactive PU resin like Fosroc Nitofill PU12F instead
- Needs a trained crew and a calibrated plural-component pump, this is a specialist applicator’s material, not a DIY crack filler
- Workability is under 2 minutes once mixed, leaving no margin for a slow crew or a stalled pump
- Site water quality affects gel time (high mineral content accelerates the reaction), so a trial batch is genuinely necessary, not a formality
- Treats a crack or joint line, not a whole elevation, it is not a substitute for a proper membrane over a large seepage area
- Shelf life is 1 year even in sealed, original packaging, and it needs UV-protected storage between 0 and 25 degrees C
Selection & best practice
Run a small field trial before committing to a production mix, inject a test shot and time the gel by hand, because ambient temperature and the mineral content of the site water both shift the reaction faster or slower than the data sheet’s 1 to 12 minute range. Space packers close enough to cover the full crack depth, keep the wall or slab temperature above 5 degrees C during injection, and where future maintenance is likely, embed a Dr. Fixit Inject RI reinjectable hose at the construction-joint stage rather than drilling packers after the fact, it is far cheaper to cast in than to retrofit.
Specifications
| Chemistry / system | Polyacrylate-based hydrophilic gel, 4-component (Part A1 emulsion, A2 accelerator, B1 catalyst, B2 water) |
| Mixed density | 1 ± 0.1 (ASTM D 1475) |
| pH | 7 to 9 (IS 9103) |
| Viscosity (Brookfield) | < 5 cP (ASTM D 2196) |
| Gel time | Adjustable, 1 to 12 minutes |
| Cured hardness | Shore 00 > 50 (ASTM D 2240) |
| Mixing ratio | Component A : Component B = 1:1 by volume |
| Pack sizes | Part A1 20 kg + A2 300 g; Part B1 350 g (Part B2 potable water site-added, approx. 20.05 kg) |
| Shelf life | 1 year from manufacture, unopened, stored between 5°C and 40°C |
Industry use cases
Metro & underground transit
Sealing precast segment and diaphragm wall joints on metro/subway station boxes needing a flexible, re-injectable gel
Residential & commercial basements
Treating raft slab and retaining wall construction joints in NCR basements damp after the first monsoon post-backfill
Water & wastewater infrastructure
Sealing hairline seepage in STP/WTP tank walls and reservoirs without draining for a membrane redo
Parking structures & podiums
Injecting slab and wall cracks in below-grade parking where surface coating access is restricted
Industrial & precast construction
Joint treatment in precast box culverts and utility ducts, often paired with an embedded reinjectable hose for future maintenance access
Frequently asked questions
Will Dr. Fixit Inject AC 300-HP stop a running or gushing leak?
Can our site plumber or mason apply this?
How do we know what gel time to set?
Can the same crack be re-injected later if it reopens?
Is it safe to use close to reinforcement steel?
What comes in the kit and how far does it go?
How we position Dr. Fixit Inject AC 300-HP
Within the Dr. Fixit range, Inject AC 300-HP is the specialist end of crack treatment, it sits above surface-level fixes like Dr. Fixit Crack-X Shrinkfree (a shrinkage-free crack filling paste for cosmetic and minor cracks) and works hand-in-hand with the Dr. Fixit Inject RI reinjectable hose system, which is what makes the re-injection feature usable in practice. For broader deck or terrace waterproofing on the same project, it is typically paired with a membrane system like Dr. Fixit Pidiproof LW+ or Raincoat rather than asked to do that job itself. Where the site condition is an active, flowing leak rather than dampness or a hairline crack, something this product’s own data sheet excludes, Space Arc’s alternative is Fosroc Nitofill PU12F, a single-component water-reactive PU resin built specifically to seal against running water; specifiers choose the Fosroc route when the leak cannot be dewatered first, and the Dr. Fixit acrylate gel when the goal is a controlled, flexible, re-triggerable seal on a joint that is merely damp or seeping slowly.
Fosroc Nitofill PU12F — Specifiers move to Nitofill PU12F, a single-component water-reactive PU injection resin, when the leak is active and flowing rather than a hairline seep, a condition Dr. Fixit’s own data sheet excludes for the acrylate gel.
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