Screed

About: Screed is a research topic. Over the lifetime, 1899 publications have been published within this topic receiving 11118 citations.

Asphalt surface renewal method and apparatus

Abstract: A method and apparatus for renewing the surface of asphaltic paving at low cost and for immediate reuse. The asphalt surface is heated to about 300°-500° F. The surface is broken to a depth of about two inches and the lower material thoroughly mixed in situ with the broken surface material. After mixing, the material is further heated to fuse the heated mixture into a homogeneous surface. The surface is screeded for leveling and compacted by a road roller. A road machine is disclosed having a steam manifold for heating the asphalt, transversely reciprocating breaker bars having teeth adjusted to the depth desired, toothed mixing cylinders for mixing the broken material, and a second steam manifold for reheating the mixed material. Reciprocating screed bars on the road machine level the mixed and heated material. Final compacting may be done with a conventional road roller.

Integrated paving process control for a paving operation

Abstract: Process control for a paving operation is facilitated by obtaining paving material conveyance information for a time period during which paving material is delivered to a screed of a paver by a material conveyance system and distributed over a surface to be paved. The paving material conveyance information includes data indicating incremental advance of the paving material to the screed of the paver during the period of time and data indicating incremental quantity of the paving material at one or more points of the material conveyance system, both of which are correlated to points in time during the time period at which the data is acquired. Incremental quantity of paving material delivered to the screed is determined to facilitate process control in the paving operation.

Road finisher and a method of applying surface layers

Abstract: A road finisher, which is used for simultaneously applying at least two surface layers comprises a chassis, a travelling mechanism, at least two premix containers arranged on said chassis, a lateral distributor associated with the respective premix container and adapted to have material supplied thereto via a conveyor path extending in the chassis, and lateral outriggers attached to the chassis as well as a dragged road-surface applying device used for applying a surface layer and arranged on said outriggers, all road-surface applying devices being high-compaction road-surface applying screeds for recompaction-free application of a surface layer, and each high-compaction road-surface applying screed constituting a rear screed, when seen in the direction of movement, which is constructed as a high-compaction road-surface applying screed which is adapted to be used for applying and compacting concrete. In the method of applying surface layers by use of such a road finisher, the surface layers are applied one immediately after the other and in one operation in such a way that each first surface layer is highly compacted during application to such a degree that recompaction is no longer necessary and each following surface layer is applied to the highly-compacted surface layer and then, in turn, highly compacted to such a degree that recompaction is no longer necessary.

Paving machine having automatic metering screed control

Abstract: A paving machine having a sensor-controlled concrete metering screed. The machine includes hydraulic cylinders which move the metering screed to various elevations to control the depth of concrete being metered out by the screed. At least one ultrasonic sensor is slide-mounted to the machine above and behind the metering screed to provide measurements of the distance between the sensor and the surface of the concrete just behind the screed. A control system compares the sensor measurements with a tolerance range of distances corresponding to the desired depth of concrete. When the sensor measurements are out of tolerance, the control system moves the metering screed up or down to bring the distance, and the metered depth of concrete, back within tolerance.

Transformable two-person floating screed with automatic grade control

Abstract: A two-person floating screed with laser-operated, automatic grade control apparatus for finishing plastic concrete is transformable for different operations. A rigid, transversely oriented float mounts a strikeoff for initially contacting and leveling rough, freshly poured concrete. In one form of the invention the screed merely floats upon the concrete surface. In an alternative embodiment, lightweight ski assemblies support the screed over the subgrade. The skis secure upwardly projecting screw jacks that removably couple to the screed and control elevation of the transverse float in response to laser signals. Each worker has a separate handle mechanism pivotally associated with the float. Separate, light-weight power sources are carried by each worker in a suitable backpack to power the screw jacks. Laser sensors mounted on vibration dampened stanchions emanating from the float respond to external laser beacons and display grade information so that the workers can make manual adjustments. With the ski assemblies attached, the laser system automatically controls float elevation by activating the screw jacks so that the extend or contract. The float preferably comprises twin sections that are secured together in the two person mode. When uncoupled, the float divides into a pair of separate, compact one-person floating screeds.