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 .
|Published (Last):||22 August 2014|
|PDF File Size:||19.13 Mb|
|ePub File Size:||15.74 Mb|
|Price:||Free* [*Free Regsitration Required]|
Electrochemical techniques for measuring metallic corrosion – Test methods for on site measurement of resistivity of concrete. The penetration of water under pressure is a test 29 recommended in Spanish Structural Concrete Code EHE 30 to measure water permeability in concrete. Climent Universidad de Alicante Spain. Permeability of Concrete as a Criterion of its Durability.
Download Online For Free Guia Para El Proyecto Y La Ejecucion De Micropilotes En Obras Pdf By Aavv
Several studies have shown that mortars and concretes prepared with cements containing blast furnace slag perform well in many applications 6 — 8particularly for structures in marine environments 9 — They are used in retaining structures, micropilotess abutments and landside control 4.
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.
All micropilotds grouts studied here also met these specifications, with the exception of the CEM I materials with a w: While the legislation on micropiles 1 — 3 establishes certain minimum compressive strength values, the codes on soil anchors 45 leave this decision micropilotea the designer’s discretion.
Figure 7 shows the compressive strength findings for cylindrical and prismatic specimens made with both types of cement. The Spanish guide for designing and building micropiles in road works 2 envisages w: Further to the electrical resistivity and post-submersion absorption findings for micropillotes 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.
Cylindrical specimens 10 cm in diameter and 15 cm high were moulded and then cut into disks 1 to 5 cm thick to study vuia water absorption and determine effective porosity.
Portland cement grouts made with the same w: About The Authors J. Post-submersion absorption furnishes information on the pore volume in a material.
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. Effective porosity was determined from the following equation [ 1 ], further to standard UNE Indeed, in the day specimens, all the CEM III grouts studied had similar or lower effective porosity, micgopilotes of water penetration under pressure and steady state chloride diffusion coefficients than the CEM I grout with a w: Pre-trial specimen conditioning may have also affected these short-term effective microplotes findings.
Ortega Universidad de Alicante, Spain.
Cimentec, S.A. – Nos dedicamos a la construcción de cimentación
Three prismatic and two cylindrical specimens were tested per cement type and w: The coefficient was calculated with Equation [ 2 ] below, proposed by Andrade et al. The results of this test for each type of cement and w: Study by impedance spectroscopy, en: Keywords Ground granulated blast-furnace slag; Cement grout; Special geotechnical applications; Durability; Compressive strength.
Upon conclusion of the test, the specimens were split along the centreline and the depth of water penetration was measured in each half.
Moreover, the fact that early age electrical resistivity values were similar in the two types of cement studied, but slightly higher for CEM I at w: This parameter was determined with the capillary absorption method described in Spanish standard UNE 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 findings are likewise consistent with the results of the other parameters studied. Eight samples were tested per cement type and w: Consequently, given the relationship between microstructure and durability in cement-based materials 1314blast furnace slag additions reduce their permeability and enhance their resistance to aggressive agent ingress 8 Lastly, although 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.
Because the grout in these applications hardens in contact with the surrounding terrain, exposing it to possible aggressive agents, its properties were characterised from very early ages 2 days and up to 90 days. These findings may be related to the substantial microstructural refinement attendant upon slag hydration 6728in which additional C-S-H phases form 12giving rise to a more compact pore network.
For soil anchors, the Spanish guide for designing and building soil anchors in road works 4 provides that grout compressive strength is to be defined in the design. The high short-term effective porosity observed for CEM III may be related to the slower reaction rate that characterises slag hydration, as discussed earlier in connection with the electrical resistivity and absorption findings.
This parameter is an indirect measure of connectivity and pore size in a material. The main conclusions that can be drawn from the present findings are listed below. 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. Tests were conducted on 2-,and day specimens.
Those texts also establish a range of acceptable water: Chloride resistance in grout is an area of particular interest, since these ions are among the most aggressive corrosion inducers in reinforcement embedded in micropiles and soil anchors, particularly in marine environments or structures in contact with high chloride- or sulfate-content water. 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.
The findings for this parameter are depicted in Figure 3. In the day specimens, the highest resistivity values were recorded for the CEM III grouts, a finding that concurred with earlier reports Although this test micropilotess actually designed for hardened concretes cured under water 29it was mlcropilotes here to the cement grout because the standards on micropiles 2 microppilotes soil anchors 4 refer to the provisions of Spanish Structural Concrete Code EHE for characterising most grout properties Tests were conducted on 2- 7-,and day specimens.
The protocol for monitoring soil anchor construction laid down in the aforementioned guide 4 suggests that compressive strength should be determined in 7- and day grout.
Keywords Aggregate Characterization Composite Compressive strength Concrete Durability Mechanical properties Mortar Portland cement Waste treatment cement characterization micropilots strength concrete micropilotees durability fly ash mechanical properties microstructure mortar physical properties.
Pastor Universidad de Alicante – Consulteco, S. Norma UNEMadrid.