Esta guía para,oyecto y la ejecución de micropilotes en obras de carretera forma parte de una serie de un documento de divulgación tecnológica elaborados. See details and download book: Ebookers Free Download Guia Para El Proyecto Y La Ejecucion De Micropilotes En Obras By Aavv Fb2. Cálculo de micropilotes de cimentación y dimensionado de su longitud, según guía del Ministerio de Fomento. ESFUERZOS Y REACCIONES. Cálculo de Viga .
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The use of one such special geotechnical application, micropiles, has grown significantly in recent years in light of its adaptability to all manner of terrains and its aptness for underpinning existing foundations, among others 12. Soil anchors are another type of special geotechnical application.
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Those texts also establish a range of acceptable water: They are used in retaining structures, bridge abutments and landside control 4. It also provides that in grout used as anti-corrosion protection for the reinforcement the w: Compressive strength is the main parameter used by codes and standards 1 — 5 to ascertain whether a given type of cement is apt for use in soil anchors and micropiles.
Despite these imcropilotes, the difference in day strength between the two types of cement was not overly large. Spanish and European codes on micropiles 23 call for a day or the age when the micropile is loaded, if prior to that time compressive strength of at least 25 MPa in cylindrical specimens.
Portland cement grouts made with the same w: The high short-term effective porosity observed for CEM III may be related to the slower reaction rate that characterises slag hydration, micrppilotes discussed earlier in connection with the electrical resistivity and absorption findings.
How to cite item. Keywords Aggregate Characterization Composite Compressive strength Concrete Durability Mechanical properties Mortar Portland cement Waste treatment cement characterization compressive strength concrete corrosion durability fly ash mechanical properties microstructure mortar physical properties.
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Study by impedance spectroscopy, en: The results observed micropilots the properties related to durability studied consequently appear to indicate that the grout prepared with cement carrying a high slag content affords greater soil anchor and micropile durability than portland cement grout. The Spanish guide for the design and construction of soil anchors in road works 4 calls for a w: The aforementioned findings appear to show that the use of cements with a high blast furnace slag content in cement grout for soil anchors and micropiles leads huia a more refined microstructure in the hardened grout than observed in the portland cement-based material, although the pore volume was not observed to decline significantly.
Pre-trial specimen conditioning may have also affected these short-term effective porosity findings. A comparison of the findings for the aforementioned semi-prisms to the FHWA-SA 1 compressive strength requirement reveals that all the grouts studied would be code-compliant the micropilotss strength recorded was Lastly, mciropilotes the day strength was lower in the grouts prepared with cement containing a high proportion of blast furnace slag than in the portland cement grouts, most of the former group would comply with the requirements laid down in the applicable codes and standards.
About The Authors J. Corrosion and Chloride Transport; T4.
???? Ebookers Free Download Guia Para El Proyecto Y La Ejecucion De Micropilotes En Obras By Aavv Fb2
Article Tools Print this article. Further to the electrical resistivity and post-submersion absorption findings for hardened grout designed for micropiles and soil anchors, when made from cements with a high blast furnace slag content the material has a more refined pore network than when prepared with a comparable portland cement. Ortega Universidad de Alicante Spain. The findings also indicate that the w: That notwithstanding, as explained above, this test was conducted because the codes and standards on soil anchors and micropiles 24 explicitly provide that grout must be EHEcompliant User Username Password Remember me.
At longer hardening times, these adverse consequences of high temperature drying would be mitigated by the refinement of the CEM III pore network, as shown by the electrical resistivity results discussed earlier. These findings are likewise consistent with the results of the other parameters studied. Electrical resistivity readings furnish information on pore connectivity and size in materials, both of which parameters are associated with durability.
Grouts were prepared with two commercial cements, a type I The characterisation of cement grouts for soil anchors and micropiles is of cardinal importance for the prevention of reinforcement corrosion. All the grouts studied here also met these specifications, with the exception of the CEM I materials with a w: This result concurs with previous reports 628according to which blast furnace slag refines the cement pore network but such refinement does not translate into any material reduction in total porosity.
Nonetheless, if design specifications call for compressive strength greater than such minimum values, and blast furnace slag cement grout in which strength gain is slower is to be used, the micropiles or soil anchors concerned should be loaded at a later age, depending on the w: The samples were extracted from the 1 cm thick disks. In Spain cement grout for micropiles is usually prepared with type I portland cement, although no cement type is explicitly specified in the Ministry of Internal Development’s guide for designing and building micropiles in road works 2whose provisions in this regard are confined to minimum compressive strength and cement strength class.
These aluminates, formed as a result of the hydration of the high Al 2 O 3 content in blast furnace slag, react with chlorides to form chloraluminates, thereby preventing ion diffusion across the material The findings for this parameter are depicted in Figure 3.
This procedure has been used in the past for fly ash- and blast furnace slag-blended cement Here it was determined in cement paste specimens using the Wenner four-point test 20 described in Spanish standard UNE Their day strength is, however, lower than observed for the portland cement grouts.
The Spanish guide for designing and building micropiles in road works 2 envisages w: Figure 7 shows the compressive strength findings for cylindrical and prismatic specimens made with both types of cement. Effective porosity, in turn, is directly related to the volume of pores accessible to water and therefore to aggressive agents such as chloride ions, which may corrode the steel used to reinforce micropiles and soil anchors.
Moreover, strength gain in slag-blended cement is known to be slower than in portland cement 728requiring more time to reach comparable strength values. This parameter was determined with the capillary absorption method described in Spanish standard UNE The cm diameter samples were used to study the variations in electrical resistivity and the cm specimens to determine compressive strength and the penetration of water under pressure.
In this study, effective porosity was the parameter used to assess durability, for water is the main vehicle for the ingress of aggressive agents in cement-based materials Durability and Degradation of Cement Systems: This study, as noted earlier, aimed to analyse the behaviour of cement grout, not concrete.