Reflections of concrete floors
Reflections on Concrete Floors: the obvious choice for excellence. Over 50 years of flooring excellence, transcribed from Samson's Reflections on Concrete Floors technical guide for architects, engineers, and specifiers.
Information for architects and engineers about fine quality concrete floors
Architectural considerations
For Architects it is the maximization of human comfort. The Texas Institute of Illumination Engineers has identified that plain concrete absorbs 60 to 70 percent of the light that strikes it. Conversely, light reflective floors can provide the level of lumens required for a comfortable working environment with lower energy light sources. Architects also like the decorative flexibility of alternative tints.
Independent reflectivity testing on Samson MBFT Light Grey dry-shake, measured across the visible spectrum (400 to 700 nanometers), shows reflectivity in the region of 50 to 65 percent, compared with 80 to 90 percent for a standard white tile, confirming a genuinely light-reflective floor finish rather than a plain grey concrete surface.
What engineers want
For Engineers, durability and energy saving are primary objectives for their clients' satisfaction. Concrete surface beds do not achieve their design strength in the top few millimeters, due to bleed water destroying water/cement ratios and therefore durability. The old fashioned "granolithic" two-course system has been replaced by monolithic dry-shake hardeners. Samson dry-shake hardeners are uniquely formulated to easily combine with bleed water. This provides a surface water/cement ratio which gives a 60MPa surface applied to a 30MPa or 25MPa design strength concrete, as illustrated by the conceptual abrasion resistance curve, in which strength rises sharply as abrasion resistance wear (loss of mass) falls.
Samson floor treatments combine to provide the triple benefits of high strength, colour, reflectivity, and ease of cleaning, proven on projects from MAKRO England, to an air flight simulator in Singapore, to a factory floor in Modderfontein.
Measuring reflectivity
Colour analysis computers are capable of measuring the nanometer wavelengths of the spectrum of light reflected from a concrete surface. On a rough surface, light striking the floor scatters in many directions as diffuse light. On a polished surface, light instead undergoes specular reflection, where the angle of incidence equals the angle of reflection, producing a much brighter, more directional reflection back into the working space.
Effect of various light sources
Lighting may be sodium high-density, halides, mercury vapour, or LED, and each of these sources will show a different spectrum and level of reflectance depending on the shade of floor that it strikes. Samson can advise on optimal selection of floor colours for the light sources in use.
Examples of Samson system success
The international "warehouse" wholesaler IKEA adopted Samson light reflective floor hardeners for their project at Damansara Mutiara in Kuala Lumpur, Malaysia. The light levels provided in the car park gave a welcoming arrival experience which IKEA considered part of their marketing image. Makro has utilized the Samson system internationally in over 55 stores, including installations in China and at B&Q Taiwan.
The Samson system
The Samson system is comprised of the selected dry-shake hardener, starting at the initial set and finishing at the final set phases of the concrete. Samson MBFT is uniquely formulated with wetting aides and components which lower the surface friction co-efficient between the generated pastes and selected spring steel blades, fitted to a six-blade finishing power float, to produce fine quality floors.
The concrete finishing time profile follows the phases of set: awaiting set, powder application and floating during the initial set, power trowelling and final finish during the final set; and this profile shifts later on the clock for a retarded set and earlier for a rapid set, illustrated across a typical 14-hour window from concrete placement.
Following the final finish, a chemically reactive liquid densifying and curing agent is applied and, after agitation by brush, the inactive residue is washed off with water. Subsequently, regular washing with normal rotary cleaning machines, and even diamond-impregnated pads, will give a satin gloss to the floor which enhances its reflectivity.
Sample specification
Tender BOQ
| Item | Bill description | Unit | Bill quantity |
|---|---|---|---|
| 1.1 | Apply to all indicated concrete surfaces Samson (insert selected dry-shake; insert selected colour or plain) dry-shake floor hardener, added at (insert selected application rate per square metre). Samson Densifier HC to be applied at the appropriate time and washed off after the chemical reaction has taken place. Followed by (insert selected sealer, if any) after full cure of substrate (21 to 28 days). All in accordance with the manufacturer's instructions. Supplier: Samson Technologies. | m² | 6050 |
MBFT dry-shake may be manually or mechanically applied, dependent on the contractor's equipment.
Optional additional sealers
Where a non-staining water and oil penetration treatment is required (for example washing bays in a motor vehicle servicing facility) the following additional specification for final sealing may be added. To the finished and densified concrete surfaces apply Samson MM Sealer Siloxane at a rate of 8 to 10 square metres per litre with a suitable soft pad applicator. MM Sealer Siloxane is a liquid repellent that renders the floor non-slip when wet: when trafficked, water is dispersed to the side, resulting in a better co-efficient of friction.
Where a polished gloss finish is desired, the Samson MM Sealer Combo may be specified. After application by a soft pad and sufficient drying, a normal janitorial rotary polisher fitted with a suitable 3M polishing pad should be used. In some circumstances even a high speed (1000 r.p.m.) burnishing polishing machine may be specified.
Some facts about concrete "hardeners"
- Only dry-shake floor hardeners can provide a 60MPa concrete at the wearing surface. The best defence against dusting, abrasion, and early wear is a Samson dry-shake that is densified and appropriately sealed.
- Liquid densifiers (sodium, lithium, or colloidal silicate), often claimed to be "hardeners", cannot increase surface strength. Densifiers however have an important role in preventing dirt adhesion and therefore ease of cleaning.
- Water repellent sealers provide a non-slip characteristic when wet, and prevent oil and fat penetration and attack from products like vinegar, wine, and tomato sauce, all sorts of oily and acidic products found in supermarkets and households. Dependent on the floor's performance requirements, a densifier may be used without additional sealers.
- The lifetime serviceability of a hard wearing, abrasion resistant floor is ensured by the use of a dry-shake hardener. MBFT dry-shake floor hardener offers a significant cost saving in comparison to repairs of a high traffic floor not correctly installed and treated.
MBFT is available in a wide variety of colours, including Blast Furnace Grey, Light Grey, Settled Grey, Southern Tan, and Timbavati. Light Grey is ideal for use in warehouses and stores.
Selection chart info
| Product / Other | Product description |
|---|---|
| SDS Standard dry-shake floor hardener | Densifying and strength enhancing dry-shake treatment for concrete floor surfaces. |
| MBFT | Pigmented densifying and strength enhancing dry-shake treatment, 60 MPa. |
| MBFT P | Powdered polymered dry-shake floor hardener for improved chemical resistance. |
| Densifier HC | Hydroxide conversion densifier and chemical pore blocker for fresh and hardened concrete. Aids curing. |
| MM Sealer Siloxane | Methacrylate sealer for hydrophobic oil barrier and rubber grip, water repellent. |
| MM Sealer Combo | Methacrylate sealer for hydrophobic oil barrier and rubber grip, water repellent and can polish to sheen. |
| Siloxane Solution | Injection resin to stop rising damp and for general water repellency. |
Selection chart
| Description of floor | SDS | MBFT | MBFT P | HC | MM Sealer Siloxane | MM Sealer Combo | Siloxane Solution |
|---|---|---|---|---|---|---|---|
| Warehouse | 5 to 7 kg/m² | Yes | |||||
| Shopping Centre | 5 kg/m² | Yes | optional | optional | |||
| Health reason to wash down / exposure to chemical attack | 5 kg/m² | Yes | Yes | ||||
| Back of Store: colour not required | 5 kg/m² or | 5 kg/m² or | 5 kg/m² | Yes | |||
| Lodges: General/Reception | 5 kg/m² | Yes | Yes | ||||
| Lodges: Wet areas (Kitchen/Bar etc.) | 5 kg/m² | Yes | Yes | ||||
| Parking garages | 5 kg/m² or | 5 kg/m² | Yes | optional | optional | ||
| Vehicle workshop / Wash bay | 5 kg/m² | Yes | Yes | ||||
| Fibre suppressant | 3 kg/m² | Yes | optional | optional | optional | ||
| Abattoirs / Food processing / Chicken processing | 7 kg/m² | Yes | Yes | ||||
| Dry-pack granular screed: House / Lodge | 5 kg/m² | Yes | optional | optional | optional | ||
| Aircraft hanger | 7 kg/m² | Yes | optional | optional |
Sealer is optional dependent on performance requirements.
Case study: Stealth Bomber Hangar in Waco, Texas
The American Delta wing stealth bomber required a very specialized hangar.
No windows were allowed, and even air had to be specially filtered with directional fans for application of perfect surfaces by spray of specialized paint. The Delta wings introduced a problem regarding lighting: sources of light could only be placed at ceiling level. Under the shade of the wings, the minimum lumens required by trade unions could not be met without bouncing light from the floor up under the wings.
David Samson was asked by the engineers to provide a solution to this problem. He acquired a book published by the Texas Institute of Illumination Engineers, which helped to establish some guidelines, then considered the spectrum of light produced by various light sources provided by General Electric. Light meters were used to establish reflectivity percentages of various concrete colours. Untreated plain concrete in a clean, pristine state was found to reflect 40% of the light that struck it. Immediately, there was dirt degradation (such as oil spillage); reflectivity would go as low as 20%, in other words the concrete was absorbing 80% of the light that struck it, and therefore wasting the energy that was utilized to produce the light in the first place.
Ultimately, a particular grade of light grey dry-shake surfacing was selected for compatibility with mercury vapour light generation and specialized crystal parabolic light shades. David Samson was then involved in pre-construction trials with a Mexican managed concrete floor installer. Several trial panels were laid and each of the three light sources was directed at the panels at a specified angle, then light meters were used to measure the reflectivity. The blue spectrum of mercury vapour lighting was the most successful in illuminating polished metallic parts under the delta wing of the bomber.
Authorities allowed a South African onto a militarily sensitive site because he had a Canadian driver's licence. Despite the South African accent, the then Canadian employers of David Samson got the contract.
Technical data (powder product)
Dry-shakes put the benefit of triple blend binders where they count, at the top wearing surface of concrete floors. Samson dry-shakes are uniquely formulated: the mathematics of optimal mechanical packing of aggregates are applied, and specific surface area of CEM I 52,5 and that of binders down to nano-sized particles has been used to calculate proportioning. This applies to:
- MBFT: moisture barrier floor topping
- MBFT P: polymered moisture barrier floor topping
- SDS: standard dry-shake floor topping
Compressive strength
Samson dry-shakes, tested in 70mm or 50mm cubes and mixed with water to produce a 25mm slump, will at full cure achieve over 75MPa. Rebound hammer testing on finished floors has indicated a lower strength development curve; a third curve reflects the average strength development of a design strength 25MPa concrete, and a fourth, conceptual curve reflects that the surface strength of unhardened concrete varies considerably according to the skill of placing of finishing crews.
Effect of application rates
3 to 4 kg/m² of applied dry-shake will normally provide a surface strength of 45 to 55 MPa. 5 to 6 kg/m² of applied dry-shake will normally provide a surface strength of 55 to 65 MPa. Application of dry-shake at more than 6 kg/m² will provide a thicker depth of protection but will only marginally add to compressive strength, except in the case of a concrete with high bleed characteristics.
Curing
Samson dry-shakes are formulated to require no water curing, membrane forming curing compound, or plastic sheeting; the application of Densifier HC ensures surface strength and the locking in of moisture required for curing.
Packaging
All grades of Samson dry-shakes are packaged in 25kg moisture-proof bags.
Shelf life
Properly stored in dry, cool conditions, Samson dry-shakes have a shelf life of about nine months. Where expired stock is proposed for use, the products should be pre-tested to ensure retention of properties.
Technical data (liquid products)
Densifier HC
Description: Densifier HC is an aqueous solution of reactive silicates and a non-foaming surfactant. Densifier HC can be applied to concrete as soon as it is hard enough not to be damaged by the applicator, or at any time deemed desirable on cured concrete.
Advantages: Densifier HC reacts with hydroxides included in Samson Dry-shake formulations, as well as those generated by the cementitious binders in the product. Densifier HC cures fresh concrete without forming a membrane. The product is useful for the curing of dusting on concrete floors and also inhibits penetration of oil and other damaging materials. Densifier HC is useful in the process of diamond disc polishing for exposure of aggregates on concrete (for this application, request detailed information from Samson Technologies).
Application: Densifier HC is best applied by spray onto dry concrete and then spread with a suitable soft brush or fibre mop to keep the product moving, to promote thorough chemical reaction. The process of brushing or mopping should be continued for about 30 minutes, and then it is important that the reacted material be removed by thorough washing with water. If during application the product thickens, it may be kept mobile by the spraying on of water. The average application rate is 8 to 10 m² per litre, but this is dependent on the porosity of the concrete being treated. Request the Samson Technologies detailed method statements to be given to site personnel.
MM Sealer Combo
MM Siloxane Combo is simply MM Siloxane with a hard wax component introduced to promote shine when floors treated with the product are buffed by rotary polishing machines. The main advantage of this buffable grade of sealer is that it gives a better long lasting shine when this is required for aesthetic purposes. All other advantages of the product are as for MM Siloxane.
MM Sealer Siloxane
MM Siloxane is simply a siloxane with an added dissolved methacrylate resin.
Advantages: The methacrylate resin component provides a surface membrane in addition to the penetration of the siloxane. This makes the product more effective where fatty products, oils, mayonnaise, or alcohols are likely to be spilled onto the floor. The methacrylate component also introduces a non-slip characteristic to wet concrete floors.
Siloxane Solution
Clear penetrating treatment for inducing water repellency.
Description: Siloxane Solution is a solvent-carried reactive siloxane for use on concrete and other mineral based materials (not suitable for marble).
Advantages: By repelling ingress of liquids (such as water, soft drinks, wines, vinegar, and similar), Siloxane Solution helps prevent staining and acid degradation of concrete floors. The product leaves no membrane, and on evaporation of the solvent leaves concrete looking untreated except for its liquid repellency. Wetted concrete treated with Siloxane Solution does not change colour, and liquids can be easily mopped up.
Application: Siloxane Solution is best applied by spray and then spread with a fibre mop to prevent pooling. On Samson Dry-Shake treated floors the application rate is 10 to 15 m² per litre.
Precaution: The solvent used in Siloxane Solution is flammable, and good ventilation is required to prevent applicator discomfort.
Packaging (all liquid products): 25 litre and 5 litre containers.
Shelf life: Indefinite, if properly stored.
Just some of our projects
National projects: Auto & General Telesure, Barloworld Distribution Centre, Bell Equipment, Boxer Stores, Clover Clayville, Cradlestone Mall, Gautrain Tunnels, Halewood International, Hatfield Mall, Kusile Power Station, Premier Foods, Wonderboom Park Shopping Centre, Gibela Train Manufacturing Facility, BMW Nelspruit, Ahrlac Airplane Manufacturing Facility, Leroy Merlin Boksburg, Impala Vleis (North West), Luhambo Student Accommodation (Mbombela), CTM Lonehill, and Woolworths Cape Town.
International projects: Big Box, Singapore; Canadian Aerospace, Singapore; Chung Cin, Taiwan; Desa City Park Hospital, Malaysia; IKEA, Indonesia; Makro Korea; and B&Q China.
Ask for Samson by name: here's why
- Products and advice that work
- Locally manufactured, readily available
- Backed by experienced team
- Simplified method statements available
- International project references
- Competitively priced
- Driven by integrity and excellence