ADDITION FOR PRODUCING THERMALLY CONDUCTIVE MORTARS AND STRUCTURAL CONCRETE

Abstract

The invention relates to an addition for producing thermally conductive mortars and structural concrete, said addition being a specific powdery formulation in each case, which, when added as an addition to a conventional concrete or mortar, allows the production of a structural concrete or mortar with improved thermal characteristics (thermal conductivity ). If the addition is added to a conventional concrete in a plant, a structural concrete with increased thermal conductivities is produced, which can adapt to the thermal requirements of the building, thereby being highly suitable for the heat activation of structures or the geothermal activation of foundations. The concrete containing the addition takes on special rheological characteristics which, inter alia, allows a self-compacting concrete to be produced. If the addition is added to a conventional mortar in a mixer, a mortar is produced with very high thermal conductivities which make it highly suitable for geothermal probes.

Claims

1. An additive for thermally conductive structural concretes and conductive mortars, characterized in that it contains between three and six components depending on its application, selected from the following components: Fine aggregate (calcareous or siliceous) with a grain size of less than 4 mm, in a proportion comprised between 0% and 95% of total weight. Fine aggregates (calcareous or siliceous) with a grain size of less than 0.064 mm, in a proportion comprised between 0% and 95% of total weight. Polycarboxylate ether superplasticizer type powder additive or derivatives thereof in a proportion comprised between 0% and 15% of total weight. Cellulose ether or biopolymer type viscosity modulator or derivatives thereof in a proportion comprised between 0% and 10% of total weight. Natural or synthetic graphite with high thermal conductivity in a proportion comprised between 0% to 45% of total weight. Graphene and/or carbon nanotubes (nanomaterials) to obtain the high thermal conductivity characteristics in a proportion comprised between 0% to 20% of total weight. A pozzolanic material such as silica fume, pozzolana or fly ash in a proportion comprised between 0% to 95% of total weight.

2. The additive for thermally conductive structural concretes and mortars, according to claim 1, characterized in that it contains: 80% of calcareous fine aggregates of a size smaller than 4 mm 13% of calcareous fine aggregates of a size smaller than 0.064 mm 1.9% of superplasticizer additive 0.1% of viscosity modulator additive 5% of finely powdered conductive graphite. Obtaining average resistances greater than 55 MPa, very dense and self-compacting and thermal conductivity of approximately 3.5 W/(K.Math.m).

3. A method for obtaining greater or lesser conductivity of the additivated concrete or mortar by means of the additive for thermally conductive structural concretes and mortars, according to claim 1, consisting of modifying the indicated proportions of the additive of claim 1 or adding a greater or lesser amount of additive to the concrete or mortar for thermally conductive structural concretes and mortars.

Description

PREFERRED EMBODIMENT OF THE INVENTION

[0018] Although the possible total dosages may be very high depending on needs, particularly those relating to mechanical resistances and conductivities, a preferred embodiment would be that concrete for the foundations of a building with geothermia where there is a need to activate said foundations in order to use the geothermia for efficient and renewable climate control, without heavy investment in a probe field to fully supplement climate control and possible sanitary hot water (SHW) needs.

[0019] If a conventional concrete typified or designated as HA-30/B/20/IIb is that used, it is advisable for the cement used to be of the CEM I type; if using a CEM II type cement, preliminary verifications must be made to avoid possible unexpected interactions.

[0020] In conventional concrete, it is not necessary to modify the dosage of the cement, the usual worksite additives (plasticizers), coarse aggregates and fine aggregates. But the amount of water or w/c (water/cement) ratio is possible to make an adjustment as a consequence of mixing with the thermal additive.

[0021] For each m.sup.3 of conventional concrete indicated (2,500 kg/m.sup.3), in this preferred embodiment 50 kg of thermal additive are added per m.sup.3 of conventional concrete.

[0022] Thermal additive containing: [0023] 80% of calcareous fine aggregates with a size of less than 4 mm [0024] 13% of calcareous fine aggregates with a size of less than 0.064 mm [0025] 1.9% of superplasticizer additive [0026] 0.1% of viscosity modulator additive [0027] 5% of finely powdered conductive graphite

[0028] When added to the described concrete, a structural concrete with a w/c ratio of 0.57 was obtained, with average resistances greater than 55 MPa, very dense and self-compacting. The thermal conductivity of approximately 3.5 W/(K.Math.m) is very convenient for a terrain with high granite-type conductivity, such as that of the preferred embodiment.