Concrete Texture and Cure Machine

Overview

A concrete texture and cure machine is the last machine over a fresh concrete slab on a paving train. It does two jobs in one pass: it rakes a texture into the still-plastic surface for skid resistance, and it sprays a liquid curing compound over the slab to seal in moisture so the concrete hydrates properly instead of drying out. Both jobs are time-critical. The texture has to be cut while the concrete is still workable but firm enough to hold the grooves, and the curing compound has to go on right after, before surface water evaporates and the slab starts to dry. Doing both from one self-propelled rig keeps the timing tight and consistent across the whole pavement.

The machine straddles the slab on a Self-propelled Frame gantry. The Tining Unit unit cuts the texture, the Spray System system lays the compound from the Compound Tank, the Engine and Hydraulics unit drives everything, and the Control System system ties the work to ground speed while the operator runs it from the Operator Station.

The straddle frame

The Self-propelled Frame is a gantry that spans the lane on four wheels running on the base outside the fresh slab, so nothing touches the concrete except the tines and the spray. A telescoping Gantry Beam beam adjusts to the paving width, and each Support Leg carries the gantry on a Drive Wheel with its own Wheel Motor and a Steer Cylinder for steering. A Leg Cylinder on each leg sets ride height so the machine follows the grade and crossfall of the slab. The machine steers to follow the pavement edge, often off the same stringline the paver used, so the texture stays square to the slab.

Texturing the surface

The Tining Unit unit creates the skid-resistant surface. A Tining Carriage sweeps across the slab on a Linear Guide Rail driven by a Ball Screw and a Carriage Drive, carrying a Tine Comb head fitted with a row of spring-steel Tine fingers. A Tine Cylinder lowers the comb so the tines drag through the plastic concrete and cut grooves, usually across the lane and at randomized spacing to reduce tire whine. For a finer finish, or as a first pass, the machine can trail a Burlap Drag cloth or artificial-turf drag that leaves a light longitudinal texture instead of deep grooves. The depth and pattern are set to the road authority's specification for the friction the finished pavement needs.

Spraying the curing compound

Right behind the texturing, the Spray System system seals the slab. A Compound Pump draws compound from the tank and pressurizes a Spray Bar carrying Spray Nozzle tips spaced so their fans overlap into an even film with no gaps or heavy streaks. A Flow Meter checks the rate and Section Valve section valves switch groups of nozzles on and off to match the slab width. Because wind can blow the spray off the slab and leave dry patches, a Wind Shroud surrounds the bar to contain the mist. An even coat is what holds water in the concrete; a thin or patchy coat lets the surface dry too fast and crack.

Compound tank and agitation

The curing compound is held in the Compound Tank. Most highway compounds are white-pigmented so they reflect sunlight and keep the slab cool, and that pigment settles out if left still, so a Agitator turned by a Agitator Motor keeps the solids in suspension. A Suction Strainer on the suction keeps lumps out of the pump and nozzles, and a Level Gauge shows the operator when a refill is due. Consistent agitation is what keeps the sprayed film the right color and concentration from the first metre to the last.

Power and control

The Engine and Hydraulics unit is a Diesel Engine driving a Main Pump that feeds the Valve Bank for the wheels, carriage, and pumps, with oil in the Hydraulic Reservoir cooled by the Cooling Package package. The Control System system makes the finish uniform: the Machine Controller reads a Speed Sensor and adjusts the Spray System output so the compound rate per square metre stays constant whatever the travel speed, with a Rate Sensor confirming it. The operator works from the Operator Station on the Operator Platform, using the Control Console and a Operator Display on an LCD Panel.

Use in the paving train

This machine runs last in the slipform paving sequence, behind the paver and any finishing equipment. Its window is narrow: the concrete must be firm enough to hold a texture but still moist enough to seal, so the machine keeps pace with the paver and works the slab while it is in the right state. Highway and airport specifications set the texture depth for skid resistance and tire noise, and the curing compound rate to control early-age moisture loss, so both functions are checked and recorded. By combining texturing and curing on one speed-controlled rig, the machine delivers a consistent friction surface and a properly cured slab across the full length of a paving run, which is why it is standard on mainline concrete paving.