A Spanish research group from the Department of Architecture of Alcala University has developed a new modified mixture of lime and cement with improved thermal and acoustic characteristics. This mixture is applicable to interior and exterior walls in new constructions and rehabilitations or to restore the built heritage. The group seeks manufacturers of conglomerates materials and construction companies specialized in rehabilitation to reach licensing agreements, collaboration and commercial agreements with technical assistance.
New and innovative aspects
- The compositions and dosages of the mixture are an improvement of thermal and acoustic aspects compared with conventional mixed mortar.
- The compositions and dosages of the mixture that give it an adequate mechanical strength without other material to protect it.
- No need to be protected with a better mechanical and durability performance finished on the face where you have applied the mixture.
Main advantages of its use
- The mortars coefficient of sound absorption improves.
- Improvement in the compound’s thermal capacities.
- Applicable on interior and exterior walls, in new construction and rehabilitation or restoration of built heritage
The present invention is a modified mixture of lime and cement with improved thermal and acoustic characteristics. The new mixture is applicable to interior and exterior walls, in new construction and rehabilitation or in built heritage restoration. The mixture is characterized by the following components: a hydraulic conglomerate, an aerial conglomerate, a siliceous aggregate or calcareous of discontinuous granulometry without fine fraction, a light aggregate with a maximum size of 4 mm (expanded perlite, expanded shale, expanded clay or a mixture thereof), short fibers of cellulose or polypropylene and / or mineral pigments.
In the scope of the present invention is preferably to use a mixture of white cement and aerial lime as conglomerate that improves the setting time of lime, increases the hardened strength and reduces soluble salt content what is related to pathologies in constructed heritage. Furthermore, the use of white cement and lime in the mixture allows adapting to the aesthetic requirements, because of being pigmentable with the use of metal oxides.
In a materialization of the proposed mixture, it is preferred the use of conventional aggregate with calcareous or siliceous nature which present a discontinuous granulometry where the fine fraction has been excluded to ensure that the material’s porous structure is suitable for increasing the value of sound absorption.
To achieve the reduction in the density of the mixture and reduce the thermal conductivity values, the group resorts to the use of lightweight aggregate that partially replace the aggregate of the mixture. These lightweight aggregates do not represent more than the 7% weight in dry of the mixture to prevent that the mechanical and durability properties could be affected by a lower density when the lightweight aggregate is incorporated.
The water that should be added into the mixture is related to the cement hydration and to the plastic consistency necessary to use in construction. It has merely to avoid decreases in strength and to limit the retraction. The variability in the added water is mainly due to the lightweight aggregate, being the expanded slate which demands more water for proper mixing
The mixture, which is made according to the description provided, is characterized by a density between 1400 and 1900 kg/m3 and a characteristic compressive strength value between 2 and 12 MPa and flexural strength between 1 and 4 MPa. It also has a conductivity temperature value between 0.45 and 0.15 W/ mK and a sound absorption value equal or higher than 0.10.
- Applicable to interior and exterior walls in new constructions and rehabilitations or to restore the built heritage..
- Construction sector and manufacturers of conglomerate materials