Shotcrete and Gunite

Wet-mix shotcrete arrives at the nozzle with its mixing water already batched, then compressed air accelerates it. Dry-mix gunite conveys dry cement and aggregate through the hose and adds water at the nozzle. Harrowgate selects the process by volume, access, stop-start frequency, reinforcement, finish, supply, and specified performance.

Yes, when the structural design and specification permit pneumatic placement. Shotcrete can form structural walls, linings, repairs, and complex profiles with one-sided or minimal forms. It does not remove the need for engineered reinforcement, cover, joints, embeds, testing, curing, and dimensional control. Harrowgate coordinates those requirements before selecting the placement sequence.

Specified 28-day strengths of 30, 35, and 40 MPa are common on Ontario work, and higher or early-age requirements can be designed. Strength alone does not define acceptance. Exposure class, water-to-cementing-materials ratio, permeability, air system, consolidation around steel, thickness, curing, and core quality can be equally important to the structure.

A panel proves the proposed mixture, equipment, orientation, reinforcement detail, and crew can produce acceptable in-place material before or during the structure. Cut sections and cores reveal voids, laminations, rebound pockets, and incomplete bar encapsulation that the finished face can hide. Harrowgate builds and shoots panels to the project’s CSA-based testing plan.

We secure the reinforcing, review congestion and shooting access, start placement behind and around bars, control nozzle angle and distance, and remove rebound before it can be buried. Laps, couplers, corners, and dense mats receive deliberate attention. If the reinforcement geometry blocks proper encapsulation, we resolve it with the engineer before production placement.

Yes, with an approved mixture, controlled pass thickness, stable substrate, suitable set response, and protected working environment. Cold-weather work requires heated materials or enclosure conditions as specified and protection of fresh concrete from freezing. Overhead work requires disciplined output, rebound removal, and curing so material remains bonded instead of sagging or drying prematurely.

Provide structural drawings, repair quantities or survey, design thickness, specified strength and exposure, reinforcement, finish, access, elevation, hose route, placement volume, testing, curing, working hours, and site water and power. Photographs help, but a site review is important where geometry, substrate condition, congestion, ventilation, or staging controls production.