Field testing device and method for determining the dynamic modulus of elasticity of asphalt

Abstract

Field test device for determining the dynamic modulus of elasticity of asphalt, comprising a loading device (1) consisting of a guide rod (4) with a notching device (5) attached thereto, a drop weight (8), a spring element (7) and a mounting cap (6), and a loading plunger (2) having a plunger surface (14) and a substantially cylindrical plunger shaft (9) having the plunger surface (14) on one end face and a plunger head (10) on the other end face, wherein the plunger shaft (9) is movably arranged in a guide element (3) in the longitudinal direction of the plunger shaft (9) and the guide element (3) has a bearing surface (18) with a through-opening (16) that can be placed on an asphalt surface (24), the plunger shaft (9) extends through this through-opening (16) such that the plunger surface (14) rests on the asphalt surface (24),the stamp head (10) has a mounting plate (11) for the force-fit coupling of the loading device (1) and an acceleration sensor (12) for detecting the time course of the acceleration of the loading stamp (2) and a displacement sensor (19) for detecting the movement of the loading stamp (2) are arranged on the guide element (3).

Description

[0001] The invention relates to a field testing device and a method for determining the dynamic modulus of elasticity of asphalt. A preferred application of the invention is the determination of the dynamic modulus of elasticity of asphalt in asphalt that has been poured or installed as a road surface.

[0002] The dynamic modulus of elasticity of asphalt, whether poured or installed as a road surface, is typically determined using the splitting tensile stress test. For this test, a cylindrical specimen is taken from the asphalt layer under investigation. A sinusoidal compressive stress is applied to the specimen via two load-bearing rails positioned diametrically opposite each other on its cylindrical surface (see the guidelines for determining the stiffness and fatigue behavior of asphalt using the splitting tensile stress test as an input parameter for dimensioning, AL Sp-Asphalt 09, German Road and Transportation Research Association, 2009 edition, pp. 10-16). The tensile stress generated in the specimen primarily causes material fatigue and ultimately leads to the specimen's failure.

[0003] The specimen is subjected to a force-controlled, harmonic sinusoidal pulsating load without pauses, at various load levels and frequencies. The load is continued and increased until macrocracks appear in the specimen. The test force and the deformation of the specimen perpendicular to the direction of the test force are recorded. The dynamic modulus of elasticity is calculated from these values. If the dynamic modulus of elasticity increases with repeated loading of the specimen, the curve of the dynamic modulus of elasticity as a function of the number of loads is a measure of the stiffness of the asphalt. If the curve of the dynamic modulus of elasticity decreases as a function of the number of loads, this is a measure of the fatigue behavior of the asphalt.The splitting tensile swelling test is complex and can only be performed in a laboratory, meaning that test results are only available a considerable time after sampling and, due to the sampling process, are associated with permanent damage to the asphalt surface under investigation. It is therefore not suitable as a field test.

[0004] German patent DE 10 2008 035 565 A1 states that the load-bearing capacity of asphalt in its uncured state can be determined using a falling weight tester in accordance with technical testing standard TP BF-StB Part B 8.3. In particular, the dynamic modulus of elasticity, referred to in DE 10 2008 035 565 A1 as the dynamic deformation modulus, of the test surface is determined. A falling weight tester according to the aforementioned testing standard comprises a load plate with a diameter of 300 mm and a mass of 15 kg, and a loading device consisting of a falling weight, guide rod, spring element, and release mechanism. The mass of the falling weight is 10 kg, and the total mass of the guide rod is 5 kg. The falling weight exerts a force of 7.07 kN on the load plate. An acceleration sensor is coupled to the load plate, by means of which the movement of the load plate placed on the test surface as a result of the force impulse of the falling weight is recorded.The dynamic modulus of elasticity of the test surface is calculated from the movement of the load plate, i.e., from the movement of the test platform resulting from the force impulse. However, the dynamic modulus of elasticity determined in this way is not a specific property of the asphalt within the asphalt layer, but rather a property that describes the dynamic behavior of the entire system of layers beneath the test platform, i.e., the compacted soil, the base courses built on top of the compacted soil, and the final asphalt layer. The dynamic modulus of elasticity as a material property of the asphalt within the asphalt layer cannot be determined with this falling weight device.

[0005] German patent DE 10 2007 035 348 A1 describes a falling weight test device for determining the deformation characteristics of soils under defined impact loads. The falling weight test device comprises a load plate designed to rest on a test surface, with a sensor unit coupled to the load plate and equipped with a displacement, velocity, or acceleration sensor; a guide rod; a loading device comprising a falling weight with a spring element connected to the falling weight; and a data processing and evaluation unit. For the intended use of the falling weight test device, the load plate is placed on the test surface, and the loading device is operatively connected to the load plate in such a way that the falling weight, dropping from a predetermined height onto the load plate, generates a dynamically cushioned, defined impact force and transmits it into the test surface.The desired deformation parameters are determined from the movement of the load plate as a result of this force impulse. The dynamic modulus of elasticity, a material property of asphalt used as a test surface, cannot be determined with this falling weight device.

[0006] US Patent 2007 / 0131025A1 describes a penetrometer for investigating soil properties, such as penetration resistance or shear strength. The penetrometer consists of a substantially elongated shaft with two flanges arranged at a predetermined distance along the shaft, a drop weight movable between the flanges along the shaft, and a conical tip located at one end of the shaft. The conical tip is driven into the soil by force impulses generated by lifting the drop weight to an upper flange and then releasing it so that it impacts the lower flange. The drop height and the weight of the drop weight are predetermined. The penetration of the conical tip is recorded and evaluated as a function of the number of force impulses.This relationship is usually compared to a predefined standard, and conclusions are drawn about the soil's properties. The dynamic modulus of elasticity, a material property of asphalt, cannot be determined with this penetrometer.

[0007] The ramming device described in DE 20 2010 009 539 U1 is also used to investigate soil properties. As already described in US 2007 / 0 131 025 A1, this device also uses a pointed ramming rod to drive a driven rod into the ground by impacts generated by a falling weight moving along a guide rod and striking an impact plate from a predetermined height. The drop height and the weight of the falling weight are predetermined. The penetration depth of the ramming rod tip is recorded and evaluated as a function of the number of impacts. The penetration depth of the ramming rod tip, as a function of the number of impacts, allows conclusions to be drawn about the soil properties. Soil investigations up to a depth of 6 m are possible with such devices. However, the dynamic modulus of elasticity, a material property of asphalt, cannot be determined with this ramming device.

[0008] Based on the aforementioned prior art, the invention aims to provide a field testing device and method for determining the dynamic modulus of elasticity of asphalt, which delivers test results quickly, i.e., without the time lag caused by sampling and laboratory analysis. Furthermore, the handling of the field testing device and the application of the method should cause no or only negligible permanent damage to the asphalt surface being tested.

[0009] This purpose of the invention is fulfilled by a field testing device comprising the features of claim 1 and a method comprising the features of claim 6. Advantageous embodiments of the field testing device are described in claims 2 to 5. Claims 7 and 8 include advantageous embodiments of the method for determining the dynamic modulus of elasticity using an advantageous field testing device according to claims 4 and 5.

[0010] A field testing device according to the invention for determining the dynamic modulus of elasticity of asphalt comprises a loading device consisting of a guide rod with a notching device attached thereto, a drop weight, a spring element, and a cap, and a loading plunger with a substantially cylindrical plunger shaft, on one end of which a plunger surface is formed and on the other end of which a plunger head is formed. The plunger surface is oriented transversely to the longitudinal axis of the plunger shaft. The elements of the loading device are designed and arranged such that one end of the guide rod is closed off by the cap, and the notching device is arranged on the guide rod in the region of the opposite end. The spring element is located on the side of the cap facing the guide rod.The drop weight has a preferably central through-hole through which the guide rod passes. It is arranged so that it can slide freely along the guide rod between the release device and the spring element. The field test device further comprises a guide element with a bearing surface that can be placed on an asphalt surface and a through-hole terminating in this bearing surface. The through-hole and the plunger shaft of the load plunger are designed and arranged correspondingly to each other such that the plunger shaft extends longitudinally through the through-hole, with its plunger surface facing the bearing surface. The load plunger is longitudinally movable within the through-hole in the guide element to such an extent that the plunger surface can project beyond the bearing surface.The head of the loading ram has a mounting plate to which the mounting cap of the loading device can be positively coupled, such that a force impulse can be transmitted from the mounting cap to the loading ram in the longitudinal direction of the ram shaft. An acceleration sensor is fixedly mounted on the loading ram, which can be used to record the acceleration of the loading ram over time. A displacement sensor is arranged on the guide element so that the longitudinal movement of the loading ram in the through-hole of the guide element can be detected.

[0011] In a preferred embodiment of the field testing device, a support plate with a bearing surface is arranged at one end of the guide element, the bearing surface of the support plate forming one end of the guide element and being perpendicular to the longitudinal axis of the guide element. The support plate enables the guide element, and consequently the stamping surface of the load stamp, to be positioned securely on the asphalt surface to be tested, preventing slippage.

[0012] The guide element is also preferably designed as a guide tube and the load-bearing plunger as a circular cylinder with a circular plunger surface.

[0013] In a suitable embodiment of the aforementioned invention, the circular stamping surface of the loading ram has a diameter of 10 mm to 60 mm, preferably 30 mm. The drop weight has a mass of 8 kg to 20 kg, preferably 10 kg. The drop height of the drop weight is dimensioned by positioning the release device on the guide rod such that the drop weight exerts a force of 5 kN to 15 kN, preferably 6.28 kN, on the loading ram.

[0014] Preferably, the accelerometer and the displacement sensor can be connected to a radio module for wireless transmission of the recorded data and values ​​to an electronic storage and evaluation unit. The transmission of the recorded data and values ​​to the storage and evaluation unit preferably occurs via radio transmission. The radio module of the displacement sensor is expediently mounted on the guide element, and the radio module of the accelerometer on the load cylinder.

[0015] To determine the dynamic modulus of elasticity of asphalt, it is first heated to a temperature between 40 °C and 60 °C. The bearing surface of the guide element is placed on the asphalt surface to be tested and positioned. The loading plunger is inserted into the through-hole of the guide element, such that the plunger surface rests flush on the asphalt surface and the plunger can move perpendicular to the asphalt surface within the guide element. The loading device is then connected to the loading plunger by placing the mounting cap of the loading device onto the mounting plate of the loading plunger. This allows a force impulse generated by the loading device to be transmitted longitudinally along the plunger shaft to the loading plunger.Against the force of gravity, the drop weight is moved along the guide rod into a raised position and locked in place by the release mechanism. The guide rod is aligned approximately vertically. The spring element is located at the lower end of the guide rod (in the direction of gravity), i.e., near the coupling point between the loading device and the loading plunger, and rests on the mounting cap. The drop weight is released and, due to the force of gravity, moves in an accelerated motion along the guide rod towards the aforementioned coupling point between the loading device and the loading plunger. It strikes the spring element at the lower end of the guide rod. Upon impact, a force impulse is generated, which is transmitted to the loading plunger along the longitudinal direction of the plunger shaft.The force impulse is introduced into the asphalt via the stamping surface of the loading stamp. The loading stamp penetrates the asphalt, causing elastic and potentially permanent deformation. The acceleration of the loading stamp over time is recorded and temporarily stored by the accelerometer. The movement of the loading stamp is also recorded and temporarily stored by the displacement sensor. From the movement of the loading stamp, the static penetration depth of the stamping stamp's shank into the asphalt being tested is determined and compared with a predetermined minimum static penetration depth. If the determined static penetration depth is greater than the predetermined minimum static penetration depth, a further force impulse is generated at the same position on the asphalt surface, as described above, using the loading device.The acceleration and movement of the loading plunger are recorded and temporarily stored. From the plunger's movement, the static penetration depth of the plunger shaft into the asphalt being tested is determined as a result of this repeated force impulse and compared with the predetermined minimum static penetration depth. Further force impulses are generated at the same position and applied to the asphalt being tested until the determined static penetration depth of the plunger shaft, resulting from the last repeated force impulse, is less than or equal to the predetermined minimum static penetration depth.From the time course of the acceleration of the loading plunger resulting from this force impulse, which caused a static penetration depth less than or equal to the predetermined minimum static penetration depth, a total penetration depth of the plunger shaft resulting from this last force impulse into the asphalt to be tested is calculated by integrating twice and then calculating the maximum value. The static penetration depth determined from the movement of the plunger shaft is then subtracted from this total penetration depth. The remaining penetration depth is the dynamic penetration depth of the plunger shaft resulting from this last force impulse, which caused a static penetration depth less than or equal to the predetermined minimum static penetration depth. The dynamic modulus of elasticity is calculated based on this dynamic penetration depth.

[0016] In the preferred design of the field testing device with a load stamp having a circular stamp surface, the dynamic modulus of elasticity is calculated according to the equation Ed=2∗(1−μ2)∗F / π∗r∗sdyn with E d = dynamic modulus of elasticity µ = Poisson's ratio for asphalt = 0.25 F = Impulse r = radius of the stamp surface is determined.

[0017] In the equally preferred and expedient design of the field test device with a circular stamp surface of the load stamp with a diameter between 10 mm and 60 mm, preferably 30 mm, a mass of the drop weight between 8 kg and 20 kg, preferably 10 kg, and a positioning of the drop weight at a drop height which, upon impact of the drop weight on the spring element, causes a force impulse to be transmitted to the load stamp of between 5 kN and 15 kN, preferably 6.28 kN, the predetermined minimum static penetration depth has a value ≤ 0.15 mm, preferably ≤ 0.1 mm.

[0018] The invention will be explained in more detail in the following exemplary embodiment. The accompanying drawings show in Fig. 1: the basic structure of a field testing device, in Fig. 2: a field testing device placed and positioned on an asphalt surface and prepared for a testing procedure, in Fig. 3a: a curve of the recorded time course of the acceleration of the load stamp and in Fig. 3b: a curve of the time course of the penetration depth of the load stamp into the asphalt to be tested, determined by integrating the acceleration twice over.

[0019] Fig. Figure 1 shows the basic structure of a field testing device for determining the dynamic modulus of elasticity E, consisting of a loading device 1, a loading stamp 2 and a guide element 3. dof asphalt, wherein the aforementioned assemblies 1 to 3 are each shown separately. The loading device 1 comprises a guide rod 4 with a release device 5, a mounting cap 6 with a spring element 7 resting on it, and a drop weight 8. The mounting cap 6 has a concave spherical cap for mounting and coupling the loading device 1 to the loading plunger 2. The spring element 7 consists of pre-tensioned disc springs. The loading plunger 2 comprises a plunger shaft 9 and a plunger head 10. A mounting plate 11 with a spherical cap is formed on the plunger head 10. The spherical cap arranged on the mounting plate 11 is convex and corresponds in shape and dimensions to the spherical cap formed in the mounting cap 6. An acceleration sensor 12 and a radio module 13 are arranged in the plunger head 10.The end face of the punch shank 9 facing away from the punch head 10 forms a punch surface 14. The loading punch 2 is essentially cylindrical. The punch surface 14 is a circular area. The guide element 3 comprises a cylindrical guide sleeve 15 with a longitudinal through-bore 16 for guiding the punch shank 9 and a support plate 17 with a bearing surface 18, wherein said through-bore 16 extends through the support plate 17 and forms an opening in the bearing surface 18. A displacement sensor 19 and a radio module 20 are arranged at the end of the guide sleeve 15 facing away from the support plate 17.

[0020] Fig. Figure 2 shows a prepared field test device for determining the dynamic modulus of elasticity E d of asphalt, which is applied as an asphalt layer 21 onto a base course 22. Below the base course 22 is compacted soil 23.

[0021] The support plate 17 rests with its bearing surface 18 flush on the asphalt surface 24 to be tested, i.e., the surface of the asphalt layer 21. The plunger shank 9 of the load plunger 2 is inserted into the through-bore 16 of the guide sleeve 15 to such an extent that its plunger surface 14 also rests flush on the asphalt surface 24 to be tested. The load plunger 2 is freely movable in the longitudinal axial direction within the guide sleeve 15. The load device 1, with its mounting cap 6, is placed onto the mounting plate 11 of the load plunger 2, such that the two corresponding spherical caps of the mounting cap 6 and the mounting plate 11 interlock positively. The guide rod 4 is approximately vertically aligned. The drop weight 8 is in a raised position and is held in this position by the release device 5.The exact position was determined in preliminary tests and set so that the falling weight 8, after release, is subject to the effect of gravity F. s In free fall, it is accelerated to such an extent that upon impact with the spring element 7, it causes a force impulse of the loading device 1 onto the loading plunger 2 with a force of 6.28 kN.

[0022] The test procedure is carried out by actuating the release device 5 and releasing the drop weight 8. The drop weight 8 falls as a result of the force of gravity F. sGuided by the guide rod 4, the weight 8 falls essentially vertically downwards and strikes the spring element 7 with energy predetermined by its mass and fall height. The resulting impulse is transmitted via the spring element 7 to the mounting cap 6 and from there, via the positive-locking engagement of the corresponding spherical caps of the mounting element 6 and the mounting plate 11, to the loading plunger 2. The impact is then transferred by the plunger surface 14 into the asphalt being tested. As a result of this impulse, the plunger shaft 9 of the loading plunger 2 penetrates the asphalt, causing elastic and potentially permanent deformation. The acceleration of the loading plunger 2 over time is recorded by the acceleration sensor 12 and transmitted via the radio module 13 to an electronic evaluation unit (not shown), where it is temporarily stored.The movement of the load stamp 2 is detected by the displacement sensor 19 and also transmitted to the electronic evaluation unit and temporarily stored by the radio module 20.

[0023] The static penetration depth s is determined from the movement of the load stamp 2. st of the stamp shaft 9 of the load stamp 2 in the asphalt to be tested, whereby below the static penetration depth s st The penetration depth of the stamp shank 9 into the asphalt being tested is understood as the depth at which the stamp shank 9 remains after the force impulse has subsided. The static penetration depth s st This describes the permanent deformation of the asphalt layer 21 caused by the force impulse via the stamp shaft 9. The determined static penetration depth s st is measured with a predetermined minimum static penetration depth s stmin compared. Is it greater than this predetermined minimum static penetration depth s? stminWithout changing the position of the support plate 18 on the asphalt surface 24, a further force impulse is generated and introduced into the asphalt to be tested at the same location. For this purpose, the falling weight 8 is moved against the force of gravity F. s The guide rod 4 is moved and positioned by means of the release device 5. The guide rod 4 is aligned approximately vertically, and the release device 5 is actuated. A force impulse is generated as previously described and transferred into the asphalt to be tested via the ram shaft 9 of the load ram 2. The acceleration of the load ram 2 over time as a result of this force impulse is recorded, transmitted to the electronic evaluation unit, and temporarily stored. The movement of the load ram 2 is also recorded and transmitted to the electronic evaluation unit. The static penetration depth s stThe displacement of the stamp shaft 9 as a result of this force impulse is determined and compared with the predetermined minimum static penetration depth s. stmin The comparison continues. Further force impulses are generated by means of the loading device 1 as described and introduced into the asphalt to be tested via the ram shaft 9 of the loading plunger 2. The temporal progression of the acceleration and the movement of the loading plunger 2 is recorded and temporarily stored, and the static penetration depth s is calculated from the movement of the loading plunger 2. st of the stamp shaft 9 determined until the determined static penetration depth s st of the stamp shank 9 smaller than the predetermined minimum static penetration depth s stmin is. Then, the temporarily stored time series of the acceleration resulting from the last force impulse, which has a static penetration depth s, is used. st less than or equal to the predetermined minimum static penetration depth s stminThis resulted in the determination, by integrating the time course of the penetration depth s of the stamp shaft 9 of the load stamp 2 into the asphalt to be tested twice, and by calculating the maximum value, the total penetration depth s. Ges certainly.

[0024] Fig. Figure 3a shows a curve of the recorded time course of the acceleration of the loading plunger (2), wherein the plunger surface (12) of the loading plunger (2) is circular with a diameter of 30 mm, a force impulse of 6.28 kN acting on the loading plunger (2) is generated by means of the loading device (1) and the temperature of the asphalt layer (21) is approximately 50 °C.

[0025] Fig. Figure 3b shows a curve of the penetration depth s of the plunger shaft 9 of the loading plunger 2 into the asphalt under test, determined by twice integrating the acceleration of the loading plunger 2 over time. The maximum value of this curve is the total penetration depth S. Ges - It amounts to in the Fig. 3a and Fig. 3b shown specific case s Ges = 0.35 mm. The determined static penetration depth s st is s st = 0.9 mm, where the predetermined minimum static penetration depth s stmin =0.1 mm.

[0026] The dynamic penetration depth S dyn is according to the equation S dyn = s ges - s st calculated. It is calculated as S dyn = 0.26 mm.

[0027] With the parameters impulse F = 6.28 kN, radius r of the stamp surface r = 15 mm and the Poisson's ratio for asphalt µ = 0.25, the dynamic modulus of elasticity E can finally be calculated. d according to the equation Ed=2∗(1−μ2)∗F / π∗r∗sdyn to be calculated. The value calculated in this way for the dynamic modulus of elasticity E d is 950 MN / m 2 .

[0028] Using the described field testing device, the dynamic modulus of elasticity E can be easily and directly determined on site according to the described procedure. d of asphalt, which is applied as an asphalt layer 21 onto a base course 22. This is important, for example, in the construction of new roads to determine the compaction of the asphalt achieved when installing the asphalt layer 21. List of reference symbols used 1 Loading device 2 charge stamps 3 Guide element 4 Guide rod 5 Release device 6. Cap 7 Spring element 8 Falling weight 9 Stamp shaft 10 stamp head 11 Mounting plate 12 Accelerometer 13 radio module 14 stamping area 15 Guide sleeve 16 through holes 17 Support plate 18 contact surfaces 19 Position sensor 20 radio modules 21 asphalt layer 22 Base course 23 compacted soil 24 asphalt surface E d dynamic modulus of elasticity F s Gravity s penetration depth S dyn dynamic penetration depth s ges Total penetration depth s st static penetration depth s stmin minimum static penetration depth

Claims

[1] Field test device for determining the dynamic modulus of elasticity of asphalt, comprising a loading device (1) consisting of a guide rod (4) with a release device (5) attached thereto, a drop weight (8), a spring element (7) and a mounting cap (6) and a loading plunger (2) having a plunger surface (14) and a substantially cylindrical plunger shaft (9) having the plunger surface (14) on one end face and a plunger head (10) on the other end face, wherein the plunger shaft (9) is movably arranged in a guide element (3) in the longitudinal direction of the plunger shaft (9) and the guide element (3) has a bearing surface (18) with a through-opening (16) that can be placed on an asphalt surface (24), the plunger shaft (9) extends through this through-opening (16) such that the plunger surface (14) rests on the asphalt surface (24),the stamp head (10) has a mounting plate (11) for the force-fit coupling of the loading device (1) and an acceleration sensor (12) for detecting the time course of the acceleration of the loading stamp (2) and a displacement sensor (19) for detecting the movement of the loading stamp (2) are arranged on the guide element (3). [2] Field test device according to claim 1, characterized by , that a support plate (17) is arranged at one end of the guide element (3), the support surface (18) of which is perpendicular to the longitudinal axis of the guide element (3). [3] Field test device according to claim 1 or 2, characterized by , that the guide element (3) has a circular cylindrical guide sleeve (15) and the loading plunger (2) has a circular cylindrical plunger shaft (9) with a circular plunger surface (14) and the plunger shaft (9) can be inserted into the guide sleeve (15) in a longitudinal axial direction in a freely movable manner. [4] Field test device according to claim 3, characterized by , that the stamping surface (14) of the loading stamp (2) has a diameter of 10 mm to 60 mm, preferably 30 mm, that the drop weight (8) has a mass of 8 kg to 20 kg, preferably 10 kg, and that the drop height of the drop weight (8) determined by the length of the guide rod (4) and the position of the release device (5) on the guide rod (4) is dimensioned such that the drop weight (8) acts on the loading stamp (2) with a force of 5 kN to 15 kN, preferably 6.28 kN. [5] Field test device according to claims 1 to 4, characterized by , that the displacement sensor (19) and the acceleration sensor (12) are connected to a radio module (13, 20) for transmitting the measured values ​​to an electronic evaluation unit. [6] Method for determining the dynamic modulus of elasticity of asphalt using a field testing device according to claims 1 to 5, comprising at least the following method steps: a) Placing the bearing surface (18) of the guide element (3) on the asphalt surface (24) to be tested and inserting the plunger shaft (9) of the load plunger (2) into the guide element (3) such that the plunger surface (14) rests on the asphalt surface (24) to be tested, b) force-fit coupling of the loading device (1) to the loading plunger (2) by placing the mounting cap (6) onto the mounting plate (11), c) Positioning of the falling weight (8) by lifting against the effect of gravity (F s ) and lock in the raised position by means of the release device (5) and aligning the guide rod (4) in an approximately vertical position, d) Generation of a force impulse by releasing the falling weight (8), e) Recording and temporarily storing the time course of the acceleration of the load piston (2) with the acceleration sensor (12) and recording and temporarily storing the movement of the load piston (2) using the displacement sensor (19), f) Adjusting the temperature of the asphalt to be tested to a temperature between 40 °C and 60 °C in a process step preceding process step a), g) cyclic repetitive execution of process steps c) to e), wherein in each cycle the static penetration depth (s) is determined from the movement of the loading plunger (2). st ) of the stamp shaft (9) of the load stamp (2) into the asphalt to be tested is determined as a result of the respective force impulse and when a predetermined minimum static penetration depth (s) is reached or fallen below is determined. stmin) as a result of a force impulse, the cyclic repeated execution of process steps c) to e) is terminated, determining a total penetration depth (s ges ) of the stamp shaft (9) of the load stamp (2) into the asphalt to be tested from the recorded and temporarily stored time course of the acceleration of the load stamp (2) as a result of this force impulse by twice integration and subsequent maximum value calculation, calculating a dynamic penetration depth (s dyn ) according to equation S dyn = s ges - s st from the determined total penetration depth (s ges ) and the static penetration depth (s st ) for this impulse and h) Determining the dynamic modulus of elasticity (E d ) from the dynamic penetration depth (s eyn ). [7] Method according to claim 6 using a field testing device according to claims 3 to 5, characterized by , that the dynamic modulus of elasticity (E d ) according to the equation Ed=2∗(1−μ2)∗F / π∗r∗sdyn with µ = Poisson's ratio for asphalt = 0.25 F = Impulse r = radius of the stamp surface is determined. [8] Method according to claim 6 or 7 using a field testing device according to claims 3 to 5, characterized by , that the predetermined minimum static penetration depth (s stmin ) as a result of a force impulse, in which the cyclic repeated execution of process steps c) to e) is terminated, ≤ 0.15 mm, preferably ≤ 0.1 mm.

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