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Revista ingeniería de construcción

versão On-line ISSN 0718-5073

Rev. ing. constr. v.24 n.2 Santiago ago. 2009

http://dx.doi.org/10.4067/S0718-50732009000200001 

Revista Ingeniería de Construcción Vol.24 N°2, Agosto de 2009 www.ing.puc.cl/ric PAG. 119-140

 

Quality control of fiber reinforced concretes by mean of double punshing test (barcelona test)

 

Sergio Carmona Malatesta **, Antonio Aguado de Cea**, Climent Molins Borrell**, Manuel Cabrera Contreras*

* Universidad Técnica Federico Santa Maria, Valparaíso, CHILE *

* Universitat Politécnica de Catalunya, Barcelona, ESPAÑA

Corresponding author:


ABSTRACT

Traditionally, flexural testing of prismatic beams is used to characterize the strength and behavior in post - cracking regime of fiber - reinforced concretes (FRC). These tests exhibit a high dispersion in their results, and therefore invalidate the use of such tests for the systematic control of FRCs works. Also, they have the disadvantage of being complex tests, which require heavy specimens and highly qualified staff. The use of other standard tests of direct and indirect tensile strength has also been intended, which have proved very complex to implement and also have high dispersion. Aiming to solve this set of problems, an indirect tensile test based on the configuration of double punching test, called the Barcelona test, has been proposed to control tensile behavior of FRC. This test requires smaller specimens, with a high specific surface of fracture, allowing to obtain values representative of strength and toughness of materials, with considerably less dispersion than other experimental methodologies. This paper presents the results of different experimental campaigns, which validate the use of Barcelona test as a suitable methodology to systematic characterization FRC in works.

Keywords: Fiber reinforced concrete, Toughness of FRC, Barcelona test, Double - punching test, FRC control


 

1. Introduction

During the last decades the construction industry has undergone a great development, that has reached not only the calculation and design techniques, but also the concrete technology and the concrete itself. Within these new technologies fiber occupies a very outstanding place with the intention of reinforcing concrete.

In fiber reinforced concrete (FRC), toughness or energy absoption capacity has been recognized as one of the most important benefits of fiber addition, improving the cracking behavior, impact behavior, and fatigue (Gopalaratnam and Gettu, 1995).

Ideally, the FRC tensile toughness should be quantified through direct tensile test or uniaxial tension. Nevertheless, the difficulty of execution of this test prevents its use, and therefore, is recommended to determine the FRC toughness through flexural test, the one that, besides being simpler, represents the conditions of loading of many of the FRC applications (ACI, 2008).

Currently, there are a great number of standards and recommendations establishing the conditions of test and parameters to evaluate and to quantify the effect of the fiber incorporation in concrete. One of them, ASTM C 1018 (2002), specifies the flexural test with a loading at the thirds, on specimens without a notch, and the toughness is quantified through the indexes of toughness and to the first crack strength of FRC. Another recommendation widely accepted is the flexural test with central loading, on notched beams, recommended by Rilem TC - 162 (2002), at the moment European standard EN 14651 (CEN, 2005). The advantage of this method is that it is simple and is controlled through the crackmouth opening displacement (CMOD) that assures a stable propagation of the crack, even for cast in-situ concrete. The load - CMOD curve or the load - deflection obtained through it can be used to calculate the relations tensile deformation or tensile - crack width and, in this way, to evaluate the effect of fibers addition.

The problem for designers and contractors is that the parameters of behavior in the post - crack state based on beams tests, generally offers a very low accuracy. Tests performed by Bernard (1999) gave as result an average of the coefficient of variation in the post-crack behavior of 15%, for ASTM I30 index (toughness defined index, in ASTM C-1018, 1997. This is calculated by dividing the area of the load-deflection curve until a deflection of 15.5 times the first crack deflection by the area until the first crack). Similar situation happens to the three point bending test proposed by Rilem, in which a relatively high dispersion in the results, between 20 - 30% is usually obtained. For such reason, a difficulty appears to be able to determine the characteristic values of the material.

As an alternative, the flexural test has been used, according to the Belgium Standard (NBN B 15 238, 1992). However, in the introduction of that standard it is specifically established that is a characterization test and that is not applicable to the systematic control of the fibers reinforced concrete. In addition, this typology of tests requires of relatively heavy specimens, complex experimental procedures and their results present significant dispersions, because it directly depends on the specific number of fibers that bridge the crack.

Considering the above mentioned and with the purpose of having a test adapted to the systematic control of FRC performance, Aguado et al. (2005) have developed an indirect tensile test based on the double punching test (Double - Punching Test, DPT) proposed by Chen (1970), which has been denominated the Barcelona test (BCN).

This double punching test, for the case of conventional concretes does not present significant advantages, with respect to other tests of indirect determination of the tensile strength, as it is the case of the Brazilian test (Molins et al., 2008a), reason why it did not manage to prevail at the time. However, this same test, in the case of the post peak behavior of the concrete with fibers has numerous advantages against the other existing tests, reason why it seems proper to deepen in his study since, for example, with smaller weight it gives major cracking surface (or the equivalent in energy).

In this article the advantages that the double punching test presents, also known as Barcelona test are shown, in comparison to different tests recommended internationally to characterize the properties of FRC, in front of the systematic control of fibers reinforced concrete. These advantages are validated by extensive experimental program, developed from samples obtained in works realized in Barcelona in the last years and by tests realized in the Technical University Federico Santa Maria, in Valparaiso - Chile.

2. Test to determine the toughness of FRC

The direct tensile test, is considered as the more adapted way to determine the properties of fracture of brittle materials. Nevertheless, it is a test difficult to perform, with high dispersions in its results, due to the incapacity to obtain in a reasonable way uniform distributions of tension through the crack. This can be attributed to the heterogeneity of the material, to imperfections of the specimen and eccentricities during the loading process. In addition, other disadvantages exist such as the holding device of the specimen and the difficulty of assuring the stability of the test.

In the last years, the Technical Committee of RILEM TC 162 (2002) has proposed a flexural tensile test on specimens with notches. A research realized by Gettu and Barragán (2003) demonstrates that it is a robust method and is a representative test of the answer of the material. Nevertheless, the tensions post crack and the toughness parameters obtained in this test present coefficients of variation of approximately a 30%. This high dispersion that presents the measured parameters causes that the test is of difficult application as a systematic control of FRC (Saludes et al., 2007).

Normally, the FRC toughness is quantified through the area under the load - deflection (P δ) curved obtained in a prismatic beam bending test (ACI, 2008), loaded at the midspan (Figure 1), as indicated in the European standars EN 14651 (CEN, 2005) and the Japanese SF -4 0SCE, 1984a) or two loads located to the thirds of the span, as it is established in ASTM C - 1018 standards (ASTM International, 2002) of the United States, UNE 83 510 (AENOR, 1989) of Spain and NBN B 15 - 238 (NBN, 1992) of Belgium. Other recommendations based on bending tests, as much as on prismatic beams as panels, were presented in extensive by Gopalaratnam and Gettu (1995). In their article, these authors conclude that the determination of the toughness of FRC through the beams tests without notches with loads to the thirds, must be improved considering, among others, the use of prismatic specimens with length /height ratio greater than 5 and recommend the use of beams with notches and thre-point bending, using the CMOD as control variable in a system of servo test - controlled of high rigidity.

Figure 1. Flexural Tet according to Gopalaratnam y Gettu (1995) recommendations

The FRC toughness can be also determined using the compression test, as it is indicated in the Spanish standard UNE 83 508 (AENOR, 2004) and in the Japanese recommendation SF - 5 (JSCE, 1984b). In these cases, during the test the axial displacement of the specimen must be registered, by means of three mounted transducers of displacement in compressometer, that is attached on the specimen, as it is in Figure 2. Nevertheless, for great deformations, the measurements are distorted because of the crack that experiences the surface of the concrete cylinder in the post - crack rank.

Figure 2. Test setup to determine the properties of the compressive strength in FRC (Flores, 2005)

 

The quantification of the strength through an indirect tensile test or Brazilian test has been less frequent. This is a method widely accepted to indirectly determine the resistance to uniaxial traction of the concrete, mainly because it is possible to be executed on cylindrical specimens, cubical or prismatic. In addition, it is a very simple procedure and has been specified by several standards and recommendations, among them it is possible to indicate ASTM C - 496 (2002), UNE 83306 (AENOR, 1985), NCh 1170 (1977) and Rilem CP C6 (1994).

The results of some authors (Nanni 1988; Nanni 1991; Cho et al., 1992) that have used this test to determine the FRC strength, allows to conclude that the post - crack behavior obtained does not satisfactorily represent the fiber effect, because the tensile state, especially in the zone of application of the load, does not allow that the fibers dominate the post - crack behavior of the material. Against those results, this test has been considered unsuitable for the FRC basically for three reasons (Carmona etal., 1998):

(1)  the load area for great deformations, as it happens in the of post - crack state of specimens of FRC, continuously increases leading to an increase in the load even after the crack of the matrix;

(2)  the test is unstable under the displacement control; and

(3) the considerable length of the specimens allows the cracking to begin within itself, making more difficult the measurement of the crack opening and the stability control.

In order to solve the problems observed in the indirect tensile test and to benefit from the use of an experimental procedure highly spread and accepted, that uses a standardized specimen for the compressive test, Carmona et al. (1998) realized the following improvements (shown in Figure 3): the length of the specimen was reduced; the load area was limited, with the purpose of maintaining a constant width throughout the test; and the tests were realized in a servo system - controlled, using the crack opening displacement (COD) as control variable during the test. As it is possible to see in Figure 4, incorporating these improvements has made possible to perform of stable Brazilian tests, able to clearly reflect the advantage that entails the steel fiber incorporation in concretes of high strength. Nevertheless, the test turns out complex and little suitable to be used as routine control test in work.

Figure 3. Brazilian test using the modifications proposed by Carmona et al. (1998)

Figure 4. Results of the Brazilian tests realized by Carmona et al. (1998), on FRC and casts in-situ concrete (HPC - 0,0; HRF - 0.5; HRF - 1.0)

Finally, the test of the wedge or Wedge - Splitting Test (WST), proposed by Linsbauer and Tschegg (1986) and later developed by Briihwiler and Wittmann (2003), has also been used to characterize the strength of the FRC. During this test, a wedge is progressively loading a FRC specimen as it is schematically shown in Figure 5. The reduction of the wedge produces in the specimen a displacement of lateral opening of the notch that originates the appearance and stable propagation of the crack. According to Saludes et al. (2007), this is an interesting method of test since it presents a series of advantages:

•  It does not require sophisticated equipment, it can be realized in regular testing machines.

•  The test is stable.

• Thanks to the type of configuration, the displacement is in accordance with the crack opening.

• The test can be performed with prismatic or cylindrical specimens, allowing the possible extraction of samples of existing structures for its later quality control.

•  It requires low concrete volume for the test to take place, because the sample needed is smaller in comparison with other test methods, as for example in those that use beams or panels as samples.

Although this test has been successful to determine the properties of normal concrete fracture, there is not much available information for the case of the FRC. An investigation of Lófgren et al. (2004), has compared the WST with the uniaxial tensile tests and the three-point bending test, realized following the recommendations of RILEM TC-162 TDF (2002) that demonstrates the applicability of the WST test, with a general dispersion of the results which is inferior to the one obtained from the three-point bending test.

Figure 5. General scheme of the wedge test

 

3. Doble punching test

The double punching test, proposed by Chen (1970), consists of putting under uniaxial compression a cylinder by means of two cylindrical steel plates of smaller diameter (of the order of a quarter of the diameter of the test specimen), prepared concentrically superficially and below the specimen, as it is in Figure 6.

Figure 6. Configuration of the double punching test and definition of geometric parameters

During the test, the load applied through the steel plates produces a conical zone of compressions under these (Figure 7). This situation originates an increase of the diameter of the cylinder producing perpendicular tensile stress to the radial lines of the specimen. When the tensional state exceeds the concrete strength the fracture of the same takes place.

Due to the stress concentration in concentric planes, at the time of the cracking, perpendicular radial cracks to this stress range take place. The cracks propagate from the center of the specimen, specifically from the edge formed by the steel punching pin towards the surface of the cylinder. Once the formation of the first crack happens, usually one or two more cracks appear, as it is possible to see in Figure 8, in which the typical cracking planes observed in the tests are shown.

Figure 7. Compressive wedges and developed tensile stress in a cylinder subjected to double punching

Different researches have proposed equations for the calculation of the tensile strength of the concrete (ft) in the double punching test (Chen, 1970; Chen and Yuan, 1980; Bortolotti, 1988; Marti, 1989). Those generally depend on the dimensions of the specimen and of the angle of the compressive wedge at interior of the cylinder. Based on an elastic model for the circumferential and vertical stress distribution in the double punching test, developed by Wei and Chau (1999), Saludes et al. (2007), using a model of connecting rods and braces, proposed the relation:

(1)

Where P is the critical load of the material, a and h the dimensions of the specimen, defined in Figure 5. This expression has the advantage of being the only one accepting the specimen fracture and, therefore, allowing its use for the calculation of the ultimate strength in cracked bodies. In addition, it does not depend on the number of cracks that form in the body and can be used for the analysis in the post - crack rank of the FRC (Mora, 2008).

Considering that through the model of connecting rods and braces is possible to determine the tensile strength (equation 1) and the residual strength of the FRC, fundamental parameters to quantify the structural contribution of the fibers can be proposed. Saludes et al. (2007) proposed to use the double punching test for the quantification and systematic control of the fibers effect on the ductility of the FRC. For this reason the flexural test established in the Belgian standard NBN 15 - 238 (IBN, 1992) is used, the one that, as the standard indicates, is not a control test. In addition, the results of the Belgian test present high dispersions, of the order of the 20%, introducing a distorting factor in the control.

In Table 1 the characteristics of the main standard tests appear to determine the FRC properties. It is observed that the weight of the specimen specified for the double punching test is considerably smaller than the majority of the specimens used in the flexural tests, with a considerable greater crack surface. On the other hand, the coefficient variation (CV.), is among the lowest ones.

Figure 8. Cracking planes observed in the double punching tests

 

Table 1. Characteristics of the main tests used to characterize FRC

 

It is highly recommended to use a precisely centered load for obtaining coefficients of variation between 6 and 13%. This is valid to bending test (100 mmxx 600 mmxx 600 mm) and compression tests (75 mmΦ 800 mm),. However, these specimens are considerably large, with weights near 90 kg, so that they are not adapted to be used in the systematic control of the FRC.

Considering the high variability of the flexural tests and its experimental disadvantages, indicated in detail by Gopalaratnam and Gettu (1995), the double punching test, also known as Barcelona test (BCN), has arisen as a quite viable alternative to characterize and systematically control the FRC toughness, which has been validated in extensive experimental programs, those that in addition have demonstrated the great versatility that this test presents.

4. Validation and application of the Barcelona test

Equivalence between the established flexural test to NBN 15 - 238 and BCN test, has been confronted in terms of the energy absorption for the different measured parameters: load - deflection and load - circumferential deformation in the middle of the height of the specimen, respectively (Molins et al., 2007).

In order to obtain the relation, it is necessary to define the total circumferential opening displacement (TCOD) measured as a circumferential opening (ΔΦ) for the BCN test and the vertical deflection (δ) for the flexural test, the one that provides same average opening of the crack (w) in both tests.

Assuming that after the crack in the flexural test only one crack develops near the midspan and its height is almost the height of the beam, thus, two halves rotate like rigid bodies around a support (Figure 9), is possible to obtain the geometric relation between the vertical deflection and the width of the crack:

(2)

where "h" is the height of the prismatic specimen, "1" is half of the span,δ the vertical deflection, θ the rotation in the supports, w the opening displacement of the end of the crack and wNBN the average opening of the crack, considering the surface of the complete crack. Taken the geometric proportions and the specimens real size in the Belgian flexural test, the equation (2) can be rewritten like this:

       (3)

 

Figure 9. Ideal movement assumption for the flexural test after the cracking and geometric parameters involved.

A similar relation between TCOD (ΔΦ) and the average opening of the crack can be established for BCN test. It is considered that the specimen fails with three radial cracks of similar width. Normally, the tests display three radial cracks, but they usually are not of the same width. Nevertheless, this last assumption helps to correlate the results of both tests. According to the considered assumption, the relation between the average opening of the crack and the TCOD are:

(4)

where ΔΦ is the TCOD and wBCN the average width of the radial cracks.

Imposing the condition that the average width of the cracks in both tests must be equal, we have:

(5)

In order to validate the Barcelona test, in the Polytechnical University of Catalonia in Barcelona, they have considered and developed a series of experimental programs (Aguado et al., 2005). From the results obtained the geometric parameters and the conditions of load that define and characterize the test have been established.

Saludes et al. (2007) developed an ample experimental program using FRC obtained in construction sites of two stations of Line 9 of the Subway of the city of Barcelona. This program considered the study of different parameters that influence in the results of the test, including the type and content of fibers, slenderness and height of the specimen, size of the load application plate and the speed of load. With the results of each test, the energy dissipated by the specimens during the process of failure was calculated and the corresponding coefficient of variation (C.V.) of the results, those shown in Table 2.

Table 2 Maximun Coefficient of Variation obtained by Saludes (2006)

The C.V. values shown in Table 2 correspond to the máximums obtained in the different series of tests. Considering those results, the following general conditions have been settled for the execution of the test:

•  Specimen diameter (d): 150 mm.

•  Specimen height (h): 150 mm.

•  Diameter of the loading disk (a): 38 mm (equivalent to d/4).

•  Speed displacement of the piston: 0.5 mm/min.

•  Test control through the circumferential deformation of the cylinder

These conditions were specified in the UNE 83 -515 standard, Concrete with fiber - Determination of the strength in face of a crack, toughness and residual tensile strength, recently approved by AENOR (2008).

In order to compare the Barcelona test with the procedure established in the Belgian NBN B 15 - 238 standard, Saludes et al. (2007) performed tests using samples of reinforced concrete with different contents of plastic fibers (5kg/m3 and 6.5 kg/m3) and steel (25 kg/m3), obtained in the construction of the Bon Pastor station of the Barcelona Subway. From the results obtained (shown in Table 3), it can be concluded that the average dispersions (coefficients of variability respect the individual values obtained for each specimen) that are obtained with the results derived from the Barcelona test are low, in comparison with the ones obtained in the flexural test based on the NBN B 15-238 standard. For specimens tested at 28 days of age an average dispersion of 7.7% for the fully factored load is obtained; that is, 15.1% respect to the energy absorption for an opening of 3 mm measured from the origin and 17.3% for the toughness measured for a circumferential opening of 3 mm. In addition, for the researched cases, a good equivalence between both tests has been established (Figure 10), so that, the values of a given toughness using the Barcelona test (EBCN) and the energy obtained with the beam test (ENBN), can be calculated using the equation (Molins et al., 2008b):

(6)

 

Table 3. Results of Saludes et al. (2007), to 28 days, in N x mm

Figure 10. Linear regression between EBCNy EmN from the results obtained from Saludes et al. (2007)

 

Guardia and Molins (2008) performed the characterization of different high workability concretes, with and without fiber, of conventional and high strength using the BCN test, contrasting the results obtained with the characterization by means of the test established in the EN 14561:2005 (CEN, 2005) recommendation.

When comparing the BCN and EN 14561:2005 tests, a correlation has been obtained between the results of the residual strength of the Barcelona test and the residual strength calculated from the results of the flexural tests. This correlation consists of applying a factor of 1.5 to the residual strength obtained by means of the Barcelona test for a circumferential elongation of 2.5 mm value and is successfully applied to other FRC, demonstrating the applicability of the Barcelona test to the quality control of the FRC in structural applications. Also, that correlation can be used to determine the optimal fiber content corresponding to a benefit demanded from the concrete, without having to perform laborious tests of flexural beams. In addition, the results of Guardia and Molins (2008) show that the Barcelona test allows to evaluate the flexural strength of the concrete without need of performing complementary tests.

Nevertheless, the results obtained in the experimental program realized by Guardia and Molins (2008) have not been satisfactory for all the amounts of steel fibers, because, unlike the flexural test, significant differences between the results accomplished with reinforced concretes with amounts of 40 and 60 kg/m3 were not observed. From the specimens observation, it can be concluded that this fact was due to a direction in vertical planes of the fibers that took place during the split, which lowered the post - crack strength in these planes.

Mora (2008) performed another extensive experimental program that has allowed validating the use of the Barcelona test on hard concrete. In these tests specimens of different diameters (Φ = 75 mm, 100 mm and 150 mm) extracted from voussoirs used in the construction of the Can Zam section of Line 9 of the Barcelona Subway were used, those that were reinforced with 60 kg/m3 of steel fiber with shaped ends.

From those tests it was concluded that the results obtained in the Φ100 mm specimens are very similar to those obtained in the Φ150 mm specimens. Nevertheless, in the case of the Φ75 mm specimens results of indirect tensile strength with higher variation in residual and their associated toughness are obtained, with respect to the Φ150 mm and Φ100 mm specimens. It is observed that the results of the double punching test also give satisfactory results of tensile strength in the three studied diameters, with low dispersions between specimens of the same zone, and between specimens of different zones and different voussoirs.

The results of load and toughness for the<|>150 mm specimens, allow to conclude that the dispersion of results, with coefficient variation between 18 and 27% per loads, and from 9 to 17% for toughness, is in the order of an inferior magnitude, and in the worse of cases, similar to the one obtained in other tests (over 30% for the calculation of loads and toughness) used to characterize the tensile strength of the concrete and its associate toughness.

Zepeda (2008), developed in Chile an experimental program following the recommendations given by Saludes et al. (2007), but using a conventional test system, with a piston displacement control. This statement opens the door to a generalized use of this type of test since it doesn't require of additional equipment other than the one found in all laboratories.

This program included normal strength concretes (fc = 30 MPa at 28 days), reinforced with different quantities of steel fibers (40 y 80 kg/m3). During the test the loads - relative displacement curves of the load plates was obtained, used to determine the absolute toughness and the toughness indexes in a satisfactory way. In addition, in his work Zepeda compared the values of the tensile strength indirectly determined by mean of the Brazilian(fBRA) and Barcelona (fBCN) test, obtaining with the latter, as it can be seen in Table 4, significantly lower coefficient variations.

Table 4. Coefficient variation of concrete with different fiber contents

 

Finally, García (2006) concluded that, to the operational advantages that the double punching test presents, a lower cost should be added, with savings in the order of 64% when compared to the use of the bending test according to the Belgium NBN B 15-238 standard.

5. Conclusions

There are different standards and international recommendations that allow quantifying the FRC toughness, based, mainly, in the flexural test. Nevertheless, the experimental procedures and methodologies of analysis present a series of disadvantages that have been previously discussed. In addition, the results reached through them present a high variability.

The flexural test or Brazilian test has proven to be less appropriate for the systematic control of FRC, because the tensile state generated does not allow that all the energy contained in the specimens to dissipate through the cracked zone, in addition it presents other disadvantages and experimental difficulties.

The double punching test or Barcelona test has demonstrated to be adapted for the systematic control of FRC, because it requires a small specimen, that can be obtained by means of molded specimens or through concrete cores. In addition it has the advantage of which it presents a specific surface of fracture significantly greater than the beams used in the flexural tests established in other recommendations.

The results of different experimental programs, carried out using both molded specimens cores, allow establishing an average coefficient variation of 13%, locating the Barcelona test among the ones that present minor variability for the systematic control of FRC. At the same time, using this test the indirect tensile strength with lower variability than the Brazilian test can be determined.

Its procedure has been recently standardized by AENOR (UNE 83515) in Spain, setting the conditions that will allow the performance of comparative tests between laboratories.

Finally, it is possible to indicate that it is necessary to develop experimental programs that allow extending its applicability, for example, using different control systems and relating different experimental parameters that can have effect on the measurements and results reached.

6. Acknowledgments

The stay of the first author in Barcelona during the elaboration of this study was partially financed by the Civil Engineering Department of the Universidad Federico Santa Maria of Valparaiso, Chile, and the Department of Engineering of the Construction of the Polytechnical University of Catalonia of Barcelona, Spain. The tests realized in Chile were financed by Cemento Polpaico S.A. (Holcim Group).

7. References

 

Aenor (1985), UNE 83 - 306 Resistencia a Tracción Indirecta (Ensayo Brasileño), Madrid, España. 4 pp.         [ Links ]

Aenor (2004), UNE 83 - 508 Hormigones con Fibras. Determinación del índice de Tenacidad a Compresión, Madrid, España, 6pp.         [ Links ]

Aenor (2004), UNE 83 - 510 Hormigones con fibras. Determinación del índice de tenacidad y resistencia a primera fisura, Madrid, España, 6 pp.         [ Links ]

Aenor (2008), UNE 83-515 Hormigones con fibras. Determinación de la resistencia a fisuración, tenacidad y resistencia residual a tracción. Ensayo Barcelona, Madrid, España, 7 pp.         [ Links ]

Aguado A., Mari A y Molins C. (2005), Estudio de viabilidad del ensayo Barcelona. III Congreso de ACHE de Puentes y Estructuras. Zaragoza 14 - 17 de noviembre de 2005. Vol. 1. Gestión de Estructuras, pp 275 - 288.         [ Links ]

ASTM International (2002), C 1018-97, Standard Test Method for Flexural Toughness and First Crack Strength of Fiber Reinforced Concrete (Using Beam With Third Point Loading), ASTM Annual Book of Standards, Vol 04.02, Philadelphia, USA, pp 546 - 553.         [ Links ]

ASTM International (2002), C 496 - 96, Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens, ASTM Annual Book of Standards, Vol 04.02, Philadelphia, USA, pp 281 - 287.         [ Links ]

Bernard E. S. (1999), Correlations in the Performance of Fibre Reinforced Shotcrete Beams and Panels. Engineering Report CE9, School of Civic Engineering and Environment, University of Western Sydney, Nepean, Australia.         [ Links ]

Brühwiler E. y Wittmann F.H. (2003), The Wedge Splitting Test. A New Method of Performing Stable Fracture Mechanics Test". Eng. Fracture Mechanical. Vol.35, pp 117 - 125.         [ Links ]

Bortolotti L. (1988), Double Punch Test for Tensile and Compressive Strengths in Concrete. ACI Materials Journal. Vol. 85, pp 26-32.         [ Links ]

Carmona S., Gettu R. y Aguado A. (1998), Study of the post peak behavior of Concrete in the Splitting Tension Test, FRAMCOS - 3, Fracture Mechanics of Concrete Structures, Gifu flapón) 12 - 16 de octubre de 1998. Eds. H. Mihashi y K. Rokugo, AEDIFICATIO Publishers, Feiburg, Alemania, Vol. 1, pp 111 - 120.

CEN (2005), EN 14651: Test method for metallic fibered concrete - Measuring the flexural tensile strength (limit of proportionality (LOP), residual). European Committee for Standaritzation, Bruselas, Bélgica. 20 pp.        [ Links ]

Chen W. F. (1970), Double Punch Test for Tensile Strength of Concrete, ACI Materials Journal, Vol. 67 (2), pp 993 - 995.         [ Links ]

Chen W. F. y Yuan R. L. (1980), Tensile Strength of Concrete: Double Punch Test. Journal of the Structural Division, ASCE, Vol. 106, pp 1673- 1693.         [ Links ]

Cho B. El - Shakra Z. y Gopalaratnam VS. (1992), Failure of FRC in Direct and Indirect Tensile Test Configuration, Proceedings of International Symposium on Fatigue and Fracture Steel and Concrete Structures, Oxford & IBH Publ., New Delhi, India, pp 587-601.         [ Links ]

CEN (2005), EN 14651: Test Method for Metallic Fibered Concrete - Measuring the Flexural Tensile Strength (limit of proportionality (LOP), residual). European committee for standaritzation, Bruselas, Bélgica.         [ Links ]

Flores B. (2005), Propiedades del Hormigón Reforzado con Fibras de Acero Sometido a Compresión. Memoria para optar al título de Constructor Civil, Universidad Técnica Federico Santa María, Valparaíso, Chile, 96 pp.         [ Links ]

García T. (2006), Aplicació de L'Assaig Barcelona pel Control del Formigó Reforcat amb Fibres Utilitzat en la Construcció d'un Edifici Industrial Projecte de Fi de Carrera Enginyer en Organització Industrial, Escola Técnica Superior d'Enginyeria Industrial de Barcelona, Universitat Politécnica de Catalunya, Barcelona, España, 94 pp.         [ Links ]

Gettu R. y Barragán B. (2003), Direct tension test and interpretation. Proceeding of the Rilem TC 162 TDF. Workshop. Editado por B. Schnütgen y L Vanderwalle, pp 15 30.         [ Links ]

Gopalaratnam V. y Gettu R. (1995), On the Characterization of Flexural Toughness in Fiber Reinforced Concrete. Int. Journal Cement and Concrete Composites. Vol. 17, pp 239 - 254.         [ Links ]

Guardia J. y Molins C. (2008), Caracterizació del Comportament a Tracció del Formigó D'Alta Traballabilitat Reforcat amb Fibres D'Acer Mitjancant L'Assaig Barcelona. 2008 PI 01, Cátedra BMB Innovación en tecnología del hormigón. Publicacions del Dept. d'Enginyeria de la construcció, Barcelona, 290 pp.        [ Links ]

INN (1977), Hormigón - Ensayo de Tracción por Hendimiento, Instituto Nacional de Normalización, Santiago de Chile, 5 pp.         [ Links ]

JSCE (1984 a), SF - 4, Method of Test for Flexural Strength and flexural Toughness of Fiber Reinforced concet, JCI Standard SF - 4, Japan Society of Civil Engineers, Tokyo, Japón, pp 45 - 51.         [ Links ]

JSCE (1984 b), SF - 5, Method ofTest for Compressive Strength and Compressive Toughness of Steel Fibre Reinforced Concrete, Recommendation for Design and Construction of Steel Fibre Reinforced Concrete. Japan Society of Civil Engineers, Tokyo, Japón, pp 63 - 66.         [ Links ]

Linsbauer H.N. y Tschegg E.K. (1986), Fracture Energy Determination of Concrete with Cube Shaped Specimens. Zemenet und Beton,Vol. 31, pp 38-40.         [ Links ]

Lófgren I., Stang H. y Olesen J.F. (2004), Wedge Splitting Test A Test to Determine Fracture Properties of FRC. 6th RILEM Symposium on FRC BEIFIB, Varenna. Italia, pp 379 - 388.         [ Links ]

Marti P. (1989), Size Effect in Double Punch Tests on Concrete Cylinders. ACI Materials Journal, Vol. 86, p. 597 601.         [ Links ]

Molins C, Aguado A., Saludes S. y Garcia T. (2007), New Test to Control Tension Properties of FRC. ECCOMAS Thematic Conference on Computational Method in Tunnelling (EURO:TUN 2007), Editado por J. Eberhardsteiner et al., Viena, Austria, 27 - 29 agosto de 2007, Vol. 1, 11 pp.         [ Links ]

Molins C, Aguado A. y Guardia T. (2008a), Control de la Resistencia a Fisuración y Tracción Residual de HRFA Mediante el Ensayo Barcelona, IV Congreso ACHE - Congreso Internacional de Estructuras, Valencia, 24 - 27 noviembre de 2008, Vol. 1, 10 pp.         [ Links ]

Molins C, Aguado A. y Saludes S. (2008b), Doble PunchTest to Control the Tensile Properties of FRC (Barcelona Test). Material and Structures. Accepted 13 may 2008.         [ Links ]

Mora F. (2008), Distribución y Orientación de Fibras en Dovelas, Aplicando el Ensayo Barcelona Tesis Doctoral, ETSECCPB, Universitat Politécnica de Catalunya, Barcelona, España, 428 pp.         [ Links ]

Nanni A. (1988), Splitting - Tension Test for Fiber Reinforced Concrete, ACI Material Journal, Vol 85, pp 229 - 233.         [ Links ]

Nanni A. (1991), Pseudoductility of Fiber Reinforced Concrete, ASCE Journal Structural Engineering, Vol 117, 78 - 90.        [ Links ]

NBN B 15 238 (1992), "Test on Fibre Reinforced Concrete Bending Test on Prismatic Simples". Norme Beige, Institut Beige de Normalisation, Brussels.         [ Links ]

Rilem (1994), Tension Splitting of Concrete Specimen CPC6, 1975, Rilem Technical Recommendation for the Testing and Use of Construction Materials, E & FN Spon, London, pp 21 - 22.         [ Links ]

Rilem (2002), TC 162 TDF Test and Design Methods for Steel Fibre Reinforced Concrete: Bending Test. Materials and Structures, Vol. 35, p. 579 582.         [ Links ]

Saludes S., Aguado A. y Molins C. (2007), Ensayo de doble punzonamiento aplicado al hormigón reforzado con fibras (Ensayo Barcelona). Cátedra BMB Innovación en tecnología del hormigón. 1 ed. Barcelona: Publicacions del Dept. d'Enginyeria de la construcció. 338 pp.         [ Links ]

Zepeda Y. (2008), Implementacion del Ensayo Barcelona Para Hormigones Reforzados Con Fibra, Memoria de titulación para optar al título de Constructor Civil, Universidad Técnica Federico Santa María, Valparaíso, Chile, 64 pp.        [ Links ]

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