Synthetic resin mortar
Synthetic resin mortar (also reaction resin mortar ) is a low-pore and water-impermeable building material, which differs from conventional mortars due to its polymeric binders (plastics). Cement is not used here as a binding agent . The aggregate , previously called aggregate, does not have to differ from conventional cement-based mortars. Only the addition of water is no longer necessary for the hardening process. A special hardener and possibly an accelerator ensure a chemical reaction that hardens the binding agent. The curing speeds and achievable strengths are superior to those of conventional mortars.
Differentiation from cement-bound mortar and concrete
Synthetic resin concretes (also known as polymer concrete or mineral cast ) are similar to synthetic resin mortar . The components used are the same. However, the composition differs. Mortars usually contain more binder. Concrete may contain aggregates larger than 4 mm. For these reasons, the synthetic resin mortar is more likely to be used for repairs and the synthetic resin concrete is mainly used for workpiece production and machine frames. The mechanical and chemical properties and advantages over cement-based mortars and concretes are the same.
advantages
- fast curing (8 hours to 2 days)
- no capillary pore system (few pores)
- impermeable to water
- diffusion-proof
- Frost resistance
- very high chemical resistance
- smooth surface
- high tensile strength
- high flexural strength
- high compressive strength
- light weight
- good damping properties (flexible against shocks and explosions)
disadvantage
- flammable
- lower temperature resistance (−40 ° C to +100 ° C)
- high costs (factor 5–10)
- in polymer concrete danger of rust on iron reinforcement , since no alkaline protection by cement available
Other properties
- Hardening without increasing the temperature, partly in the frost area
- Curing speed adjustable for many resins
- Weathering, aging and corrosion resistance
- Abrasion consistency
- low shrinkage behavior
composition
Like all mortars, synthetic resin mortars consist of aggregates and binding agents. During processing, a hardener previously stored separately is mixed in. The manufacturer often adds accelerators to the hardener. The proportion of aggregate is a high double-digit percentage. In turn, the hardener usually only has to be added to the binder in a low single-digit percentage. The proportion of the accelerator is also low. The proportions of course depend on the manufacturer, the intended use and result and the binders used.
Aggregate
The aggregate consists mainly of dry and natural mineral raw materials: mostly gravel and quartz sand. Granite, basalt, calcium carbonate, expanded clay, perlite or other fillers can also be used (also for synthetic resin concrete).
binder
The following synthetic resins are used as binders:
Harder
Organic peroxides are used as hardeners for polyesters and methacrylate resins . Often it is methyl ethyl ketone peroxide. Liquid aliphatic polyamines and polyamidoamines are used for epoxy resin .
accelerator
Cobalt salts are often used as catalysts for acceleration .
processing
The final strength of the building material naturally depends on the processing. First and foremost, the hardener should be applied in the prescribed amount. Too little hardener means that the binder does not react completely and no thermosets or polymers are formed. The result can still look good. The resilience and long-term properties will be lower, so that the result is technically unusable.
Furthermore, the technically possible curing times are much shorter (a few minutes) than those of the mortars that can ultimately be bought. Rapid hardening with a lower proportion of binder or a higher proportion of hardener can lead to deformations and tensions in the material.
Moisture damages the result: The air humidity also has little influence on the later product. The chemical reactions during polymer formation are disturbed and water layers around the aggregate prevent the resin from adhering.
A clean container should be used for mixing; the pioneers of the Bundeswehr use a plastic bag for this. The cleaning necessary after use is time-consuming. Disposal of the vessel is to be planned. Due to the adhesive effect of the mixed raw materials, tools used must be cleaned thoroughly. This succeeds z. B. with acetone . For this reason, gloves are also necessary. Depending on the trade, appropriate footwear may also be required. And due to fumes, respiratory protection is recommended when you are not working in the fresh air. Skin contact should be avoided as parts of the mortar are moderately to severely irritating. For these reasons, professional protective clothing is essential.
When using synthetic resin concrete and cladding , common release agents are unsuitable. Hard waxes, silicones or polyvinyl alcohol are used here.
Depending on the planned use of the end product, it can be primed with chemical and weather-resistant liquid plastic. Most manufacturers offer their own system here.
Individual evidence
- ↑ http://www.baumarkt.de/lexikon/
- ↑ http://www.dornbach.com/de/baulexikon/
- ↑ http://www.helpster.de/mit-kunstharzmoertel-unebenheiten-im-beton-ausgleich-so- geht- s_64322
- ^ Hans-Gustav Olshausen: VDI-Lexikon civil engineering . Springer-Verlag, Berlin Heidelberg 1991, ISBN 978-3-662-30425-9 , pp. 652 .