Adjustable screed

Abstract

An improved screed for contouring cementitious material around a central drain is described. The screed includes a drain pivot element adapted and constructed to be rotatably secured in a drain depression. An elongated material contact element adapted and constructed to uniformly contour the surface of cementitous material is provided. A height adjustment element connects the drain pivot element to the material contact element. The height adjustment element is used to set the operating height of the material contact element, the drain pivot element is secured to the drain, and the material contact element is placed in contact with the cementitious material and rotated to contour the material surrounding the drain into a uniform, generally frustoconical configuration generally concentric with the drain.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]None.BACKGROUND OF THE INVENTION[0002]According to Lambert and MacDonald in their 1998 monograph titled “Reinforced Concrete—History, Properties & Durability” (published by the Corrosion Prevention Association, Surrey, U.K.), the oldest known surviving concrete is to be found in the former Yugoslavia and was thought to have been laid in 5,600 BC using red lime as the cement. The first major concrete users were the Egyptians in around 2,500 BC and the Romans from 300 BC. The Romans found that by mixing a pink sand-like material, which they obtained from Pozzuoli, with their normal lime-based concretes they obtained a far stronger material. The pink sand turned out to be fine volcanic ash, and they had inadvertently produced the first ‘pozzolanic’ cement. Pozzolana is any siliceous or siliceous and aluminous material which possesses little or no cementitious value in itself but will, if finely divided and mixed with water, chemically react w...

AI Technical Summary

Benefits of technology

[0014]An improved screed for contouring cementitious material around a central drain is described. The screed includes a drain pivot element adapted and constructed to be rotatably secured in a drain depression. An elongated material contact element adapted and constructed to uniformly contour the surface of cementitous material is provided. A height adjustment element connects the drain pivot element to t

Problems solved by technology

The Romans made many developments in concrete technology including the use of lightweight aggregates as in the roof of the Pantheon, and embedded reinforcement in the form of bronze bars, although the difference in thermal expansion between the two materials produced problems of spalling.

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