GX Concrete Series
Self-healing ready-mix and precast concrete formulations. Designed for structural infrastructure applications where autonomous crack management and reduced embodied CO2 are specification priorities.
Built-in repair, reduced carbon
GX Concrete Series formulations incorporate the GX gel healing additive distributed uniformly through a low-carbon cementitious matrix. The dry admixture is batched at the ready-mix plant alongside the SCM blend — no separate site application, no specialist equipment, no change to the contractor's placing and finishing operations. The existing concrete supply chain handles delivery.
Three clinker replacement levels — GX-30, GX-40, and GX-50 — allow project-specific optimisation across compressive strength target, durability exposure class, and embodied CO2 reduction goal. The healing matrix dosage (8–16 kg/m³ depending on grade) is calibrated per clinker replacement level so that autonomous sealing capacity does not diminish as SCM content increases.
Application matrix
| Application | Exposure Class | Recommended Grade | Key Benefit |
|---|---|---|---|
| Bridge deck — cast-in-place | XD3 / ASTM Exposure F2 | GX-40 or GX-50 | Chloride ingress resistance + autonomous sealing of thermal/traffic-induced cracking |
| Parking structure slab | XD2 / ASTM Exposure F1 | GX-30 or GX-40 | De-icing salt resistance + reduced seasonal repair mobilization |
| Retaining wall | XC3 / XD1 | GX-30 | Pressure-face crack control + extended inspection interval |
| Tunnel lining segment | XS1 / XD2 (wet) | GX-40 or GX-50 | Circumferential crack management, groundwater exclusion |
| Precast beam / plank | XC2 / ASTM moderate | GX-30 | Transport and erection micro-crack healing before service loading |
Design targets — GX Concrete Series
All parameters are design targets. Not EPD-certified measurements. Contact Gelmedix technical team for project-specific mix design consultation.
| Parameter | GX-30 | GX-40 | GX-50 |
|---|---|---|---|
| Clinker replacement rate (target) | ~30% | ~40% | ~50% |
| 28-day compressive strength target | ≥ 30 MPa (C30) | ≥ 35 MPa (C35) | ≥ 30 MPa (C30) |
| Water-to-binder ratio target | ≤ 0.50 | ≤ 0.45 | ≤ 0.42 |
| Target slump range | 100–150 mm | 100–160 mm | 120–160 mm |
| GX healing additive dosage (target) | 8–12 kg/m³ | 10–14 kg/m³ | 12–16 kg/m³ |
| Indicative embodied CO2 reduction vs OPC | ~25–30% | ~35–40% | ~45–50% |
Handling & curing
GX Concrete Series is designed to be handled and placed using standard concrete construction methods. No specialist equipment is required beyond that specified for the host mix design. Key parameters to observe:
- Maintain minimum wet cure period of 7 days (membrane cure acceptable) — the healing matrix activates post-set and requires adequate initial hydration
- Avoid accelerated drying cures (direct flame, direct high-heat) that may pre-degrade the healing precursor shell
- Minimum placement temperature 5°C — below this threshold, the polymerisation chemistry slows significantly; standard cold-weather concrete practice applies
- Maximum water addition at truck discharge is the same as the host mix design — no additional water for the GX additive is required or permitted