• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    There is disclosed a permeable durable concrete having a high reflection coefficient, comprising titanium dioxide.
    公开号:BE1022300B1
    申请号:E2013/0693
    申请日:2013-10-16
    公开日:2016-03-14
    发明作者:Giovanni D'ambrosio；Alberto Ghezzi；Massimo Borsa
    申请人:Italcementi S.P.A.；
    IPC主号:
    专利说明:

    PERMEABLE DURABLE CONCRETE
    The present invention relates to a durable permeable concrete.
    A draining or permeable concrete is a concrete having a high porosity, such that it will allow water to flow through voids. It generally has a reduced amount of fine aggregate and a good interconnection between the voids present in the structure, said interconnection allowing the water to flow more easily.
    As is known from the prior art, the void content of a permeable concrete can range from 10 to 35%, with a typical compressive strength of 2.8 to 28 MPa (400 to 4000 psi). The rate of percolation varies depending on the size of the aggregate and the density of the mixture, but it is generally in the range of 100 to 1500 mm / min.
    Durable permeable concrete is used for road surfacing and allows rainwater and water from other sources to enter the soil, thereby reducing out-of-site flow and allowing water recharge. underground.
    Examples of application of permeable sustainable concrete are one use for coating parking areas, low traffic areas, residential or secondary roads, pedestrian crossing areas, sidewalks, bike paths, etc.
    The durable permeable concrete is generally prepared by mixing the granulate with the pure cement paste, pouring the mixture thus obtained into the area to be coated, and applying a suitable pressure to obtain a smooth upper surface. The application of pressure on the durable permeable concrete or the compaction phase can be carried out by hand or mechanically, for example by means of a spatula, a roller, a finishing machine, etc. The use of permeable sustainable concrete is one of the practices suggested by the US Environmental Protection Agency (EPA) since permeable sustainable concrete allows the flow of water, reduces the effects of channeling and the formation of bodies of water, by ensuring the recovery of water in groundwater (deep drainage), the collection and recycling of rainwater, which can then be properly conveyed by the development of specific secondary services.
    Concretes also provide reflective surfaces that minimize the urban heat island effect. The urban heat island effect is an effect that can be attributed mainly to horizontal surfaces, such as roofs and soils, which adsorb solar radiation. Materials with a major solar reflectance (called albedo), such as concrete, reduce the heat island effect, save energy, for example by reducing the need for air conditioning, and by improving consequence the quality of the air.
    Smog levels were also correlated with temperature increase. A temperature rise of a few degrees is enough to cause an increase in the amount of smog and pollution.
    Solar Reflection is the amount of solar radiation reflected by a surface relative to the total amount of radiation reaching that surface. Solar radiation reaching an object on earth includes visible light and ultraviolet light as well as infrared radiation. Concrete produced with ordinary Portland cement generally has a solar reflectance of between 0.35 and 0.45, although these values may vary.
    The solar reflectance is commonly measured using a solar reflectometer (according to ASTM C1549) or a pyranometer (according to ASTM E1918). The US Green Building Council has adopted a composite index called the "solar reflectance index" (SRI), which is a solar reflection coefficient to measure the extent to which a surface exposed to direct sunlight heats up. The temperature of a surface depends on the reflection coefficient of the surface and its emittance, as well as solar radiation. The solar reflectance index (SRI) is used to determine the effect of reflection coefficient and emittance on surface temperature, and ranges from 100 for a standard white surface to zero for a standard black surface .
    The SRI is calculated using the ASTM E1980 method "Standard Practice for Calculating Solar Reflective Coefficient Index of Horizontal Opaque and Slightly Sloped Surfaces".
    Materials with major SRI values are the most interesting materials and are the most appropriate choice for mitigating the heat island effect. Emittance, also known as emissivity of a surface, is a measure of the extent to which a surface emits or releases heat. This value is between 0 and 1.
    A polished aluminum surface has an emittance of less than 0.1, while a non-metallic black material has an emittance of greater than 0.9. However, more opaque non-metallic materials (such as concrete, stone and wood) have an emittance of between 0.85 and 0.95, and its value is generally assumed to be 0.90.
    In addition, for these materials, the SRI value is mainly a function of the solar reflection coefficient. In other words, a building material having a high solar reflectance coefficient will be much more likely to be characterized by a high SRI value.
    Concrete floor coverings that must be considered durable in accordance with the parameters provided by the US Green Building Council must have a solar reflectance index (SRI) of at least 29.
    Although conventional concrete meets the minimum requirements of SRI, permeable concrete generally does not meet these requirements.
    The main reason why the permeable concrete is not able to reach the minimum SRI value lies in the nature of the measurement made for the SRI. Moreover, as previously mentioned, the SRI value is obtained by optical measurement by means of a reflectometer, and therefore the porous zone of the permeable concrete contributes significantly to reducing the solar reflection coefficient.
    The need to obtain permeable durable concretes having a high solar reflectance index, without, however, reducing the porosity on the surface of the permeable concrete, in other words without deterioration of the properties characterizing a permeable concrete such as the rate of percolation and the compressive strength is therefore particularly felt.
    An object of the present invention therefore lies in a permeable durable concrete having a high coefficient of reflection, comprising titanium dioxide.
    The titanium dioxide may be both titanium dioxide in rutile form and titanium dioxide in anatase form, and preferably it is titanium dioxide in anatase form.
    The amount of titanium dioxide is preferably equal to or greater than 1% by weight relative to the total weight of cement present in the fresh concrete, more preferably equal to or greater than 2% by weight.
    In one embodiment of the present invention, the permeable durable concrete comprises in the fresh state at least 230 kg / m 3 of cement, having a water / cement ratio of between 0.3 and 0.4, a quantity of granulate included between 1400 and 2000 kg / m3 with a Dmax value between 6 and 10 mm, the granulate being characterized by a particle size such that at least 85%, preferably at least 96% and better still at least 98% by volume of the granulate pass through a 6.3 mm sieve.
    The titanium dioxide may be added to the mixture as such or, in a preferred aspect of the invention, a cement already mixed with titanium dioxide, preferably TX Area cement, which already comprises a percentage of 2% is used. by weight, based on the total weight of the cement, of titanium dioxide in anatase form.
    In particular, it has been unexpectedly found that permeable concretes comprising gray cement, for which it was impossible to obtain SRI values greater than 29, when they comprise gray cement mixed with titanium dioxide, exceed said value. thresholds and meet the limits set by the US Green Building Council for sustainable concretes.
    The characteristics of the durable permeable concrete according to the present invention are particularly surprising if it is considered that it is demonstrated that the addition of "ΠΟ2 to cement unreasonably alters the luminance value, and that if the It is desired to obtain significant increases, it is necessary to arrive at additions of titanium dioxide of the order of 10% The main advantage of permeable durable concretes according to the present invention is that, by an addition which does not implies neither substantial change of the components of the permeable concrete, nor substantial change in the permeable concrete structure, it is possible to obtain improvements also of the order of 50% of the SRI value of the permeable concrete, while maintaining the properties of the permeable concrete unaltered. compressive strength and total permeability In the particular case of gray cements, this makes it possible to obtain a durable permeable concrete in accordance with the established thresholds s by the US Green Building Council on sustainable cements. Other features and advantages of the invention will become evident from reading the description.
    By the term "cement" according to the present invention is meant a powdery material which, when mixed with water, forms a paste which hardens due to hydration and which, after curing, retains its resistance and its stability also in the presence of water. In particular, the cements according to the present invention comprise Portland cement, slag cement, pozzolan cement, fly ash cement, calcined shale cement, limestone cement and so-called composite cements. For example, Type I, II, III, IV or V cements may be used in accordance with EN197-1. A particularly preferred cement is CEM II cement. The preferred class of cement is Class 42.5. It does not matter whether the cement is gray or white.
    By the term "granulate" according to the present invention is generally meant granular materials used in the field of construction (see also UNI EN 12620), which may be silicic, limestone or basaltic, round or ground.
    The granulate can be natural, industrial or recycled. The natural granulate is a granulate of mineral origin which has been unequivocally subjected to a mechanical treatment, while the industrial granulate is also a granulate of mineral origin which derives, however, from an industrial process involving a thermal or other modification. Finally, the recycled granulate is a granulate resulting from the treatment of an inorganic material previously used in the construction industry.
    Permeable concrete does not necessarily require the addition of hyper-fluidizing additives / water reducers to achieve the desired results in terms of mechanical strength, although based on cement / water ratios of between 0.3 and 0.4 .
    However, in the case where it is desired to use hyper-fluidizing additives, these may be chosen from sulfonated naphthalene (SN), sulphonated melamine (SM), modified lignin sulphonates (MLS) or polycarboxylic compounds such as polyacrylates.
    In order to increase the life of these concretes and to reduce freeze / thaw damage, it is possible to use aeration additives, preferably chosen from sodium abietate, alkylarylsulphonates, alkylsulphonates and alkylsulphates. acids derived from animal fats and oils and hollow spheres, preferably alkyl sulphates and hollow microspheres.
    The weight percentage of aeration additives is between 0.1 and 3%, more preferably between 1 and 2% by weight of the cement. The application of the durable permeable concrete according to the present invention is particularly simple thanks to the particular machinability of the mixture and, depending on the type and size of the coating, it is spread by means of vibratory road finishing machines or by hand, with appropriate construction tools, on a suitably designed substrate.
    For complete homogenization, cement, water, granulate, optional aeration additive and titanium dioxide are mixed in a concrete mixer at the construction site or similar device until a homogeneous mixture without lumps and having a "wet soil" type texture.
    The mixture is thus applied on the support leveled by a clevis and compressed appropriately.
    Once the mixture is prepared, it is best to apply it within half an hour (this period referring to a temperature of about 20 ° C). Other features and advantages of the invention will become apparent from the examples which follow, given for illustrative and non-limiting purposes.
    Example 1
    21 kg of granulate (1480 kg / m3) of calcareous type having a D max value equal to 10 mm are mixed for 3 minutes with 0.7 kg of water, ie with 50% of the quantity. total water.
    The mixture is stopped and 4 kg of TX Area gray cement (280 kg / m3) are added, the remainder of the water (0.7 kg) and 0.08 kg of Esapon aeration additive marketed by Lamberti. (laurylsulfates, 2% by weight relative to the cement). The total amount of water corresponds to a water / cement ratio of 0.35.
    The whole charge is mixed for 5 minutes.
    10x10 tiles having a thickness of 3 cm are obtained which are compacted in a suitable manner (10 strokes with a weight of 2 kg) and allowed to cure for 24 hours.
    The SRI is measured in accordance with the EN 410 standard, corresponding to the ISO 9050 standard: the durable permeable concrete sample according to Example 1 has an SRI value equal to 33.
    Example 2 / comparative)
    The same procedure as that described in Example 1 is used, employing Type II gray cement 42.5R in place of TX Area gray cement, and the measured SRI value is 22.
    Example 3
    The same procedure as described in Example 1 is used, using TX Area white cement instead of TX Area gray cement, and the measured SRI value is 61.
    Example 4
    The same procedure as that described in Example 1 is used, using white cement type II 42.5R in place of the gray TX Area cement, and the measured SRI value is equal to 53.
    It is evident that the addition of titanium dioxide, present in the TX Area white cement of Example 3, allows a significant increase in the SRI value also in a white permeable cement.
    权利要求:
    Claims (7)
    [1]
    1. High permeability durable concrete having a high coefficient of reflection, comprising titanium dioxide, in which the concrete comprises in the fresh state at least 230 kg / m 3 of cement, having a water / cement ratio between 0.3 and 0 , 4, a granulate in an amount between 1400 and 2000 kg / m3 and having a Dmax value of between 6 and 10 mm, the granulate being characterized by a particle size such that at least 85%, preferably at least 96% and more preferably at least 98% by volume of the granulate pass through a sieve of 6.3 mm.
    [2]
    2. Durable permeable concrete according to claim 1, wherein the titanium dioxide is selected from titanium dioxide in rutile form and titanium dioxide in anatase form.
    [3]
    The durable permeable concrete according to claim 1, wherein the titanium dioxide is in anatase form.
    [4]
    4. Durable permeable concrete according to any one of the preceding claims, wherein the amount of titanium dioxide is equal to or greater than 1% by weight relative to the total weight of the cement present in the fresh concrete.
    [5]
    5. durable permeable concrete according to any one of claims 1 to 3, wherein the amount of titanium dioxide is equal to or greater than 2% by weight relative to the total weight of the cement present in the fresh concrete.
    [6]
    6. Durable permeable concrete according to any one of the preceding claims, wherein the cement is a cement supplemented with titanium dioxide.
    [7]
    7. permeable sustainable concrete according to claim 6, wherein the cement contains an amount equal to 2% by weight of titanium dioxide in anatase form.
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    同族专利:
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    ITMI20121742A1|2014-04-17|
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    MA35092B1|2014-05-02|
    BG111577A|2015-06-30|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    KR20020058946A|2000-12-30|2002-07-12|이종황|Environmental affinitive building materials immobilized titanium oxide having nitrogen oxides decomposition capability|
    法律状态:
    2019-06-26| FG| Patent granted|Effective date: 20160314 |
    2019-06-26| MM| Lapsed because of non-payment of the annual fee|Effective date: 20181031 |
    优先权:
    申请号 | 申请日 | 专利标题
    IT12001742|2012-10-16|
    IT001742A|ITMI20121742A1|2012-10-16|2012-10-16|SUSTAINABLE DRAINING CONCRETE|
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