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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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 mjcropilotes in road works 2whose provisions in this regard are confined to minimum compressive strength and cement strength class.
Free Download Online Guia Para El Proyecto Y La Ejecucion De Micropilotes En Obras Pdf By Aavv
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.
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 Although this test is actually designed for hardened concretes cured under water 29 micropilptes, it was applied here to the cement grout because the standards on micropiles 2 and soil anchors 4 refer to the provisions of Spanish Structural Concrete Code EHE for characterising most grout micropilottes 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 Eight samples were tested per cement type and w: 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 nicropilotes to 90 days.
The characterisation of cement grouts for soil anchors and micropiles is of cardinal importance for the prevention of reinforcement corrosion. Both cements were compliant with reference guide micfopilotes4 minimum strength class requirements The measure of electrical resistivity of cement paste or concrete is an micrpoilotes method for determining its steady state chloride diffusion coefficient D s 20 Keywords Ground granulated blast-furnace slag; Cement grout; Special geotechnical applications; Durability; Compressive strength.
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Durability and Degradation of Cement Systems: The aforementioned findings appear to show that the use of cements with a high blast furnace guai content in cement grout for soil anchors and micropiles leads to 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.
Albaladejo Universidad de Alicante Spain.
This improvement is related to the hydraulic properties of blast furnace slag. In this study, the variation in the diffusion coefficient D s was monitored guiw the age of 90 days. The code also establishes a series of maximum depth values, depending on the type of environment to which the concrete is exposed. 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 The results of this test for each type of cement and w: Nonetheless, the effect on the in-service properties durability and mechanical strength of the slag cement grout used in special geotechnical applications such as micropiles and soil anchors has not been researched.
Cylindrical specimens micropi,otes cm in diameter and 15 cm high were moulded and then cut into disks 1 to 5 cm thick to study post-submersion water absorption and determine effective porosity.
Despite these considerations, the difference in day strength between the two types of cement was not overly large. Electrical resistivity rose with time for both types of cement studied see Figure 2denoting the progressive refinement of the pore network as a result of ongoing clinker and slag hydration 6guoa 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.
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The mechanical property studied was compressive strength, since as noted above, this is the main parameter used in codes guix standards for determining whether a cement is apt for such applications. The products formed during slag hydration induce microstructural refinement in the mortar and concrete 67 In light of the foregoing, in this study compressive strength was determined on the 7- and day specimens prepared as described above.
Standard test method for specific gravity, absorption, and voids in hardened concrete, Philadelphia. Norma UNEMadrid.
Pastor Universidad de Alicante – Consulteco, S. Most of the grouts prepared with slag-bearing cement meet the compressive strength requirements laid down in the various codes and standards for micropiles and soil anchors, whether measured on cm diameter, cm high cylindrical specimens or 4-cm square, cm deep prismatic specimens.
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 — The main conclusions that can be drawn from the present findings are listed below. The findings for this parameter are depicted in Figure 3.
After 28 days, however, porosity was substantially lower in the former.