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27 July 2020

Seawall Rehabilitation with Urethane Grouts: Fill Voids, Stabilize Soil

Posted in Geotechnical, Industrial

Seawall Rehabilitation with Urethane Grouts: Fill Voids, Stabilize Soil

Seawalls are found throughout the world along lakes, rivers, and coastlines. Although they all serve a similar purpose, there are different types of seawall configurations and designs, such as block walls, concrete walls, or steel sheet pilings - all of which are subject to the effects of water, limiting their effective lifespan and ultimately jeopardizing nearby structures.

Over time, seawalls begin to develop small defects due to fluctuating tides, and thermal expansion and contraction. Initially, these defects are insignificant and often unnoticeable. However, as water from the positive side of the seawall begins to infiltrate through the defects, contacting reinforcing steel within concrete or through joints of steel sheet piles, it enters and begins to saturate soils behind the structure. As water levels rise and fall, a vacuum is created which easily pulls the saturated supporting soils through defects into the body of water – this creates voids, settlement, depressions, sinkholes, and overall instability of the structure.

Cost-effective repair with urethane injection grouts

Avanti's injection grouts have been specifically designed to seal these defective areas from further infiltration/exfiltration by creating a watertight barrier, and fill voids that have developed by binding existing soils together preventing further erosion. Utilizing expansive urethane injection grouts – such as AV-275 Soilgrout or AV-278 Low Vis Hydro - for seawall rehabilitation has proven to be a far more expedient and economical approach to extending the life expectancy of seawall structures plagued by erosion and loss of soils.


  • AV-275 Soilgrout is a low viscosity, moisture activated, MDI-based polyurethane resin whose chemical reaction is catalyzed by mixing AV-276 Soilcat with AV-275. Injected as a single component, AV-275 is designed to react quickly with moisture to bind together and waterproof loose granular soils and fill voids. AV-275 forms a dense, impermeable, rigid soil/grout matrix, withstands wet/dry cycles and permeates well. AV-275 Soilgrout is tested and certified for NSF/ANSI/CAN 61 - Drinking Water System Components.


  • AV-278 Low Vis Hydro is a moisture activated, MDI-based polyurethane resin whose chemical reaction is catalyzed by mixing AV-279 Low Vis Accel with AV-278. Injected as a single component, AV-278 uses moisture as an initiator and is designed with soil permeation in mind – it has a low viscosity (25-100 cP) for penetration with high expansion to fill voids (expands up to 6,000%), stop active or potential water leaks, and stabilize soils. AV-278 withstands wet/dry cycles and forms a dense, closed-cell, impermeable semi-rigid foam.


For more information about how our urethane injection grouts are used in seawall rehabilitation, or any of our injection grout products or applications, contact your Avanti Regional Manager today or give us a call at 800.877.2570.