• If you expose the concrete and show it off: (exposed thermal mass [bonus only if exploited], needs to be on top of thermal insulation and Damp proof membrane: high embodied energy and carbon; floor cannot include underfloor heating)
• Dematerialises the floor (removes other finished completely but may be adding more below and may create thermal bridge where other floors are set at normal level)
• You need to strengthen it against foot traffic wear with either a coating of resinous stuff (synthetic ingredients, non-renewable, Offgassing, VOCs, hazardous waste?), or add stronger aggregates e.g. granolithic chippings (where from?) or impregnate the floor with stuff (synthetic ingredients, non-renewable, Offgassing, VOCs, hazardous waste?)
• You need to have interesting aggregate/binding to be worth showing off (and expensive labour rates to achieve highest quality consistent appearance concrete)
• And extra processes to make it look good.
• Recycled aggregates may need to be selected or they may not be beautiful
• Special aggregates may need to be brought to the site (marbles from italy?)
• Insitu structural terrazzo floors are available and expensive (marble aggregates and coloured matrix cement)
• They promote but do not require cement substitution so may be made of OPC Ordinary Portland Cement (1.8% of UK CO2 production or 8% of global CO2 production)
• PFA Pulversied Fuel Ash is from Coal fired Power Stations (CO2, other pollution, spherical, glass like, aggregate and cement replacement, desulferisation gypsum by-product or Acid rain)
• Fly Ash (I think is suspect see below)
• GGBS Ground Granulated Blastfurnace Slag Cement (waste from UK steel making, (High embodied energy and potentially high embodied carbon), cementitious, slower set, same ultimate strength, Low carbon (if you discount the steel making impacts), suitable with recycled glass aggregates (no alkali-silica reaction); warmer colour than OPC cement)
• Removes laitence (water diluted cement matrix on top surface) and flattens out surface undulations
• Need to consider diamond grinders (if industrial diamond and made in laboratories in the UK or EU might be okay, if obtained naturally need to consider the social and environmental issues and pollution associated with diamond extraction)
• Need to consider the electrical energy or fuel input to grinding/polishing kit
• The alternative is a second hand softwood scaffold board tamped across the surface by two men eating 3 shredded wheat in the morning
• They have an acoustic influence on the space and surroundings (no absorption, high reflection, longer reverberation time, impact noise, noise transfer through floor, may need acoustic isolation joints)
• Object falling on them are vulnerable to breakage rather than bounce
• Concrete shrinkage needs to be controlled and large floors must be broken up with movement control joints, the layout of which need to be considered as a design issue.
• Grinding floors with control joints is not simple, so often cut afterwards and then filled with load bearing sealants (synthetic ingredients, non-renewable, Offgassing, VOCs, hazardous waste?) or strips of metal or plastic. (high embodied energy and carbon)
• Need to consider cost (its made of concrete but does not mean its cheap)

Fly Ash

• “Coal Fly Ash Class C has worked well as an infill material for the Shaw EcoWorx carpet and carpet tile backing system.
• This is a bi product of coal combustion at electrical generating plants and is derived from particles captured from the flu gasses in electrostatic precipitators.
• Around 40% of recovered fly ash has been recycled to supplement Portland Cement in concrete production and has thus produced major savings in energy and CO2 emissions.
• Fly Ash C is not considered or treated under regulation as a hazardous waste stream, although it contains trace concentrations of heavy metals and other substances that are known to be detrimental to health in sufficient quantities.
• Potentially toxic trace elements in coal include arsenic, beryllium, cadmium, barium, chromium, copper, lead, mercury molybdenum, nickel, radium, selenium, thorium, vanadium, and zinc.
• Although no regulatory controls have been implemented there have been a number of concerns expressed by environmental groups regarding the potential for damage to human health and the environment from the processing, handling and storage of this material
• In December 2008 the collapse of an embankment at an impoundment for wet storage of fly ash at the Tennessee Valley Authority‘s Kingston Fossil Plant resulted in a major release of 5.4 million cubic yards of coal fly ash, damaging 3 homes and flowing into the Emory River.
• Cleanup costs may exceed $1.2 billion.
• This spill was followed a few weeks later by a smaller TVA-plant spill in Alabama, which contaminated Widows Creek and the Tennessee River.
• These events caused Shaw (USA Carpets) to review its use of the Coal Fly Ash C material and to seek a suitable alternative.”

ARB 2012

© GBE NGS ASWS BrianMurphy
aka BrianSpecMan
29th January 2013 – 23rd April 2017