This discussion document aims to demonstrate the viability of calcined clays as a Supplementary Cementitious Material (SCM) in concrete. The paper recommends a series of interventions to enable behavioural change, demand signalling, and widespread adoption of calcined clay in the UK.
There are many concrete surface finish specifications that can be specified, for example
Hot weather concreteing. Higher temperatures for the fresh concrete will lead to more rapid hydration and higher early age maximum temperatures.
Large area pours for suspended slabs improve both productivity and quality
Delamination is characterised by thin layers of surface mortar becoming detached from the main body of the slab. Concrete Advice Sheet 18 provides an overview of the causes of delamination in concrete floors.
Assessing the quality of concrete surface finishes is a matter of opinion since it is subjective rather than objective.
Floor coverings less than 3mm thick are frequently specified to be laid directly onto cement:sand screeds. However, when viewed in cross light, undulations that are unacceptable can often be seen. Special treatment to the surface of the screed may be needed to produce a more acceptable result.
Composite concrete/profiled steel sheet slabs are a popular form of construction for suspended floor slabs, as they are simple and economical to design and construct. Generally they are found to be satisfactory in service. However, visible cracking is one aspect that occasionally causes problems and complaints from building occupiers. As the majority of composite floors are covered (by finishes, flooring or a raised computer floor) cracking is generally not readily visible. Sometimes the floor use dictates that the surface of the composite slab is left uncovered, e.g. power trowelled floor finishes. It is on exposed floors that cracking can be an issue.