Abstract
The infrastructure plays a vital role in stimulating economic growth. Any infra project requires proper planning, design, construction, quality control (QC), and quality assessment (QA). It is important to comply with QC and QA to avoid failure and enhance the long-term pavement performance in order to provide a safe and solid system of transportation. Researchers were replacing laborious and time-consuming density-based methods (sand cone and/or core cutter) with advanced stiffness or modulus-based NDT devices for the QC of compacted geomaterials. The lightweight deflectometer (LWD) is such a highly advanced and sophisticated device that was developed to evaluate the deformation modulus (ELWD) of compacted geomaterials as an alternative of density test. This device is portable, light-weight, user-friendly, and it is ideally suitable for all constructional geomaterials. This study is intended to provide a state-of-the-art on the LWD device as well as presented the ranges of deformation modulus for various geomaterials from several studies. For instance, in the case of soils, aggregates, and asphalt materials deformation modulus values were found to be in the range of 35–60 MPa, 80–120 MPa, and 120–170 MPa respectively. In addition, several studies have been compiled to completely comprehend the relationship between LWD and various devices.
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Introduction
Road networks are one of the key components for the economic growth of any developed nation. The Ministry of Road Transport and Highways [1] proposes to develop various mega projects by connecting expressways/access-controlled/strategic, coastal and port connectivity highways, economic corridors, and border roads. Quality control and Quality Assurance (QC and QA) are the important criteria in order to ensure quality of construction, minimal maintenance, and long-term performance of pavements. The required degree of compaction needs to be achieved by controlling the process of geomaterials compaction in the field. Typically, this process involves the use of periodic in-situ monitoring of density and moisture, generally obtained by using destructive tests such as sand cone test, core cutter test and rubber balloon test as well as non-destructive tests (NDT) such as Moisture Density Indicator (MDI) and Electrical Density Gauge (EDG) which are tedious, time-consuming, laborious and sometimes not feasible to perform in accordance with the specifications, whereas Nuclear Density Gauge (NDG) releases gamma radiation, which causes a potential hazard to the user and frequency response of the Soil Density Gauge (SDG) will be influenced by the soil gradation (refer Table 1). Hence, the importance and usage of non-destructive test (NDT) devices based on stiffness/modulus has been increased and the success rate is in the range of 64–86%, compared to the density-based devices [2].
The Stiffness/modulus-based NDT devices are Briaud Compaction Device (BCD), Clegg Hammer (CH), Dynamic Cone Penetrometer (DCP), and Soil Stiffness Geo-Gauge (SSGG). In addition, various deflectometer devices are available for measuring the deformation modulus of the compacted geomaterials. Those are, dropping weight deflectometer (DWD), Heavyweight deflectometer (HWD), Falling weight deflectometer (FWD), Rolling weight deflectometer (RWD), and Lightweight deflectometer (LWD). According to Ebrahimi and Edil [3], the usage of lightweight deflectometer (LWD) has been increased to evaluate the quality of any compacted geomaterial for its ease of use, portability, without interrupting the construction activities and suitable for all types of geomaterials.
In 1981, a portable dropping weight deflectometer (DWD) was first invented and developed by the Federal Highway Research Institute (FHRI) and Headquarters of Magdeburger Prufgeratebau (HMP) Company [4]. However, research within European countries has been focused on demonstrating the usefulness and reliability through field trials. The LWD currently uses technology that is similar to trailer mounted-FWD equipment, with the reduced load pulse duration and reduced maximum applied force being the first compromise in the development of the LWD device to convert into portability. An extensive study has been carried out using the LWD device on pavement structures for QC for the past three decades. The utilization of LWD device is more reliable as it provides consistent correlation and measurements [5]. A general comparison of conventional in-situ density-based devices and stiffness/modulus-based devices are listed in Tables 1 and 2 respectively. A detailed description of the LWD operating principles, strengths and limitations, has been reported in the literature [6,7,8,9]. The main focus of this study is to present the various research works carried out by using the LWD device.
Description of LWD device and operating procedure
Figure 1 shows the schematic view of LWD device with the components. The major components of the LWD device are drop weight, loading plate, and accelerometer. Initially, place the loading plate on top of the compacted geomaterials, release the drop weight along the guide rod by ensuring a standard drop height. The drop weight is allowed to drop on buffers made of either rubber pads or steel springs and deformation of the loading plate is measured with the help of an accelerometer. The first three drops are allowed for seating to enhance the intact contact between the loading plate and compacted geomaterials. The next three consecutive drops are used to evaluate the average deformation. Finally, the deformation modulus (ELWD) can be calculated by using the well-known Boussinesq’s elastic solution (Eq. 1) for the case of a rigid or flexible base resting on an elastic half-space. Table 3 presents various LWD devices and specifications which were manufactured by various agencies.
where ELWD = Deformation modulus of compacted geomaterial (MPa), r = Radius of loading plate (mm), υ = Poisson’s ratio of the compacted geomaterial, fr = Plate rigidity factor (Fig. 3), w = Deformation of the loading plate measured at its center (mm), and q = Maximum contact pressure (MPa);
where;
F = Applied force (N) and a = area of loading plate (mm2).
Theoretically, the applied force on a surface cannot be constant, because it clearly depends on the stiffness of the buffer material on which the load is applied (Eq. 3):
where; F = Applied force (N), m = mass of falling weight (kg), g = acceleration due to gravity, 9.81 (m/s2), h = drop height (m), and c = material stiffness constant (N/m).
Factors influencing the deformation modulus
Various parameters that influence the deformation modulus of compacted geomaterials are diameter of loading plate, plate rigidity, plate contact stress, loading rate, buffer type, location, and type of deformation transducer [7, 9]. Further details on the various factors influencing the deformation modulus (ELWD) are discussed in the following sections.
Diameter of loading plate
The diameter of loading plate is in the range of 100–300 mm (refer Table 3). Researchers (Deng-Fong Lin et al., Chaddock and Brown [6, 10]) concluded that the selection of the diameter of loading plate is a significant factor that influences deformation modulus due to the reason of depth of influence. Generally, the depth of influence is equal to 1.0–1.5 times the diameter of the loading plate. In the literature, it is reported that the decrease in diameter of the loading plate leads to an increase in the deformation modulus, due to the reason of increase in contact stresses of loading plate. Chaddock and Brown [10] conducted tests on crushed rock base and subbase materials over compacted clay materials. The deformation modulus for the 200 mm diameter loading plate was found to be 1.3–1.5 times that of a 300 mm diameter loading plate. Deng-Fong Lin et al. [6], performed field studies using the LWD device on a natural sand soil deposit and found that the estimated ELWD from a 100 mm diameter loading plate was found to be 1.5–1.6 times that of a 300 mm diameter loading plate. Vennapusa and White [9] recommended 300 mm, 200 mm, and 100 mm diameter of loading plates, for the range of ELWD < 125 MPa, ELWD between 125 and 170 MPa, and ELWD > 170 MPa respectively.
Plate rigidity
The plate rigidity factor depends on the rigidity of loading plate and type of compacted geomaterials as shown in Fig. 2. Mooney and Miller [8] reported that it might be the tendency of a soil to attain a failure where the stress distribution is uniform. Das [14] stated that it may imply some consequences of the plate rigidity, but theoretically, a flexible plate shows uniform stress distribution for a loaded clayey subgrade and a true rigid plate should not deform under a load. Various thickness of plates (refer Table 3) and their materials, which cause variations in their rigidity. Plate rigidity factors (fr) under the loading plate vary with the stiffness of the plate and compacted geomaterials. Borowicka [11] proposed an analytical solution to evaluate the relative rigidity of the plate (Eq. 4).
where; K = Relative rigidity of the loading plate, Ep and Es = Modulus of elasticity of the loading plate and compacted geomaterial respectively (MPa), υp and υs = Poisson’s ratio of the loading plate and compacted geomaterial respectively, tp = Thickness of the loading plate (m) and r = Radius of the loading plate (m).
For K = 0, the contact stress distribution under the loading plate is uniform and it is considered as a flexible plate, K > 0, the contact stress distribution at the edges increases to infinity and varies at the center of loading plate, and K = ∞, the contact stress at the center of the loading plate is half of the applied stress and it is considered as a perfectly rigid plate.
Plate contact stress
The contact stress between the loading plate and the compacted geomaterials is assumed to be uniform or that of a parabolic and inverse parabolic for a rigid plate on an elastic half-space (as shown in Fig. 2). The applicability of linear elastic half-space theory to the LWD device, as well as the nature of the contact stress between the loading plate and the compacted geomaterials, must be assessed. The impact force and diameter of the loading plate are designed to deliver a peak contact stress in the range of 100–200 kPa, simulating the approximate stress pulse on a typical sub-grade or base layer caused by traffic loading on top of a finished pavement [9, 15, 17]; Nazzal et al. [16].
Most of the studies indicated that the measured deformation modulus increases with higher applied contact stress and it depends on the type of compacted geomaterials. For dense and compacted granular materials, ELWD increases with higher applied contact stress and for the materials with cementitious properties and soft subgrade soils are not influenced by change in the contact stress stated by Vennapusa and White [9]. Fleming et al. [18] found that the measured ELWD with a 300 mm diameter loading plate was increased by 1.15 times by increasing the plate contact stress from 35 to 120 kPa. Similar studies on very stiff crushed aggregate and stabilized aggregate materials shown no significant difference in the plate contact stress from 140 to 200 kPa [19].
The contact stress for the 100 mm diameter loading plate was 8–9 times that of a 300 mm diameter loading plate [6]. Bilodeau and Dore [20] conducted an experiment with both 100 mm and 300 mm diameter loading plate on Ultra High Molecular Weight Polyethylene (UHMWP) plastic material (properties similar to granular soils). The higher stresses were recorded with the 100 mm diameter loading plate. However, the contact stress distribution for the 100 mm loading plate shows flattening and/or increasing stresses near the plate edge. The assessment of contact stress under the LWD loading plate was found to be affected by the diameter of the loading plate. Hence, the contact area has a significant impact on the ELWD.
Loading rate and buffer type
The rate of loading can be regulated by changing the spring rigidity of the buffer between the drop weight and the contact loading plate and thus can affect the measured deformation modulus. Lenngren and Lukanen [21] reported that by using stiffer buffer for the case of asphalt concrete pavements, the load pulse time history was shortened and the resulting ELWD is increased by 10–20%. Lenngren and Lukanen [21] also indicated that the shape of the load pulse, its peak, and time history affects the magnitude of the measured deformations to some extent. Fleming [18] reported that a comparatively lower stiffness buffer provides more efficient load transfer and better simulates static plate loading conditions. Deng-Fong Lin et al. [6] also evaluated the effect of drop heights, concluding there was a very low impact of different drop heights on stiffness buffers.
The effect of buffer temperature and loading pulse was evaluated by Adam and Kopf [22]. ELWD was measured on the rigid laboratory floor for a fixed drop weight and height at different temperatures. Data for 10 repetitive loading has been recorded with two buffers. The applied impulse load varied approximately 30% with a change in the buffer temperature from 0 to 30 °C because the rubber buffers are slightly softened when heated due to repetitive loading because of the impact of load on the loading plate is independent of the surrounding and equipment temperature. However, it remains constant for a steel-spring buffer. Hence, the researchers recommend to using the steel spring buffers (Larsen BW et al. 2008) [23].
Location and type of deformation transducer
The various LWD manufacturers provide various transducers and their built-in position. For instance, the spring-loaded geophone is used in direct contact with the compacted geomaterial through a hole in the center of the loading plate to measure the velocity of the compacted geomaterial in Keros, Dynatest, Prima, and TFT devices as shown in Fig. 3a. Whereas, the Zorn device has an accelerometer built into the loading plate (Vennapusa and White 2009) [9] from which the readings are twice integrated to calculate deformation of the loading plate as shown in Fig. 3b. These differences seem to contribute to differences in the evaluation of loading plate deformation. The contact area of the geophone is very disturbed due to the narrow foot of the geophone, and has a relatively stiff spring buffer inside the housing to maintain contact between the geophone and the compacted geomaterials, which results in disturbance (Fleming et al. 2007) [18]. This disturbance is common on softer subgrades and some granular compacted geomaterials. However, it is not clear about the quantifying of recorded permanent deformation during the impact and effect of disturbance on ELWD. The contact area of the accelerometer loading plate has not reported any such disturbances under it, as it is built into the loading plate.
Correlations and ranges of deformation modulus (ELWD)
Since LWD tests are easy and rapid to conduct, the testing period can be significantly shortened [24]. Hence, researchers proposed the correlations (refer Table 4) between measured ELWD and other parameters like density, unconfined compressive strength, California bearing ratio, etc. The deformation of modulus range varies based on the type of LWD device used and type of material. Based on available data, the typical deformation modulus reported for various types of subgrades, subbase, base layers, granular layers, and backfilling materials are listed in Table 5.
Application of lightweight deflectometer
The LWD device is a new evolution through the use of its best practice and simple operating principle, moreover internationally recognized and widely accepted for infrastructural applications in recent years after being used over 34 years in European countries (i.e., Germany, United Kingdom, United States, Australia and New Zealand on a performance design basis). The several advantages of the methods are likely to benefit the sectors, such as monitoring of compaction activities of earthworks, pavements, runways, embankments, retaining walls, mechanically stabilized earth walls (MSE), landfills, compressibility of waste or contaminated land, marine works, treated and untreated soil, canal construction. In addition, a new testing procedure has been implemented to obtain direct measurements of resilient modulus (MR) of a compacted geomaterials using a simple technique and it was designed for both laboratory and in-situ testing [37]. Recent studies have been carried out based on the forward and back-calculation solutions, which are formulated as an inverse problem to match the predicted deformations to the observed deformations by using most existing techniques such as static back-calculations use regression equations that are fitted to a database of deformations by using artificial neural network system (ANNS) [38] and by employing gradient search or genetic algorithm iterative methods to minimize an objective function of any set of independent variables (i.e., thicknesses and layer moduli) [39].
The instant results of the compacted geomaterials obtained from LWD makes it an effective device and an ideal replacement, saving time and minimizing the cost. The deformation modulus value depends on various factors such as the diameter of the loading plate, drop height, contact stress, and flexural rigidity. Hence, researchers recommend that the range of deformation modulus values need to be exercised for a selected geomaterials by constructing a test pad before proceeding to the actual construction.
Conclusions
The lightweight deflectometer (LWD) device is an internationally recognized and widely used technique in infrastructural applications. The long-term performance of any project depends on the characteristics of the compacted geomaterials. This study provides a state-of-the-art resource for contractors and engineers by focusing on evaluation of deformation modulus by using various LWD devices and discussed the influence of various factors on deformation modulus. Several correlations between deformation modulus and other engineering properties of geomaterials like dry density, UCS, and CBR. Range of deformation modulus values were presented for various geomaterials. Infield, it is necessary to construct a test pad for evaluating the range of deformation modulus values for the corresponding geomaterials. It is concluded that the lightweight deflectometer (LWD) is a valuable and very effective device for monitoring the quality of construction as it is versatile, portable, can reduce duration, running cost of major projects, and it is suitable for all construction geomaterials. The LWD has to be deploy in India and other developing countries by the consultants, geomaterial specifiers, contractors, and clients to play a major role in QC/QA in ensuring the safe and solid system of transportation and long-term pavement performance along major road network corridors.
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Abbreviations
- QC:
-
Quality control
- LW:
-
Lightweight deflectometer
- ELWD :
-
Deformation modulus
- MoRTH:
-
Ministry of Road Transport & Highways
- SCT:
-
Sand cone test
- CCT:
-
Core cutter test
- RBT:
-
Rubber balloon test
- NDT:
-
Non-destructive tests
- MDI:
-
Moisture density indicator
- EDG:
-
Electrical density gauge
- NDG:
-
Nuclear density gauge
- SDG:
-
Soil density gauge
- BCD:
-
Briaud compaction device
- CH:
-
Clegg hammer
- DCP:
-
Dynamic cone penetrometer
- SSGG:
-
Soil stiffness geo-gauge
- FHRI:
-
Federal Highway Research Institute
- HMP:
-
Headquarters of Magdeburger Prufgeratebau
- FWD:
-
Falling weight deflectometer
- CIV:
-
Clegg impact value
- DPI:
-
Dynamic cone penetration index
- CBR:
-
California bearing ratio
- MR :
-
Resilient modulus
- ASTM:
-
American Society of Test Method
- UHMWP:
-
Ultra high molecular weight polyethylene
- GC:
-
Clayey gravel
- GW:
-
Well graded gravel
- GP:
-
Poorly graded gravel
- SP:
-
Poorly graded sand
- CL-ML:
-
Clayey silt of low plasticity
- CL:
-
Lean clay
- RAP:
-
Recycled asphalt pavement
- ANNS:
-
Artificial neural network system
- γd :
-
Dry density of the compacted geomaterial (kN/m3)
- W:
-
Water content (%)
- r:
-
Radius of loading plate (mm)
- υ and υs :
-
Poisson’s ratio of the compacted geomaterial
- fr :
-
Plate rigidity factor
- w:
-
Deformation of the loading plate measured at its center (mm)
- q:
-
Maximum contact pressure (MPa)
- a:
-
Area of loading plate (mm2)
- F:
-
Applied force (N)
- m:
-
Mass of falling weight (kg)
- g:
-
Acceleration due to gravity, 9.81 (m/s2)
- h:
-
Drop height (m)
- c:
-
Material stiffness constant (N/m)
- K:
-
Relative rigidity of the loading plate
- Ep :
-
Modulus of elasticity of the loading plate (MPa)
- Es :
-
Modulus of elasticity of the compacted geomaterial (MPa)
- υp :
-
Poisson’s ratio of the loading plate
- tp :
-
Thickness of the loading plate (mm)
- CBR(us) :
-
Unsoaked California bearing ratio (%)
- CBR(s) :
-
Soaked California bearing ratio (%)
- UCS:
-
Unconfined compressive strength (kN/m2)
- Ev1 :
-
Static modulus of layer 1 (MPa)
- Ev2 :
-
Static modulus of layer 2 (MPa)
- ELWD-P3 :
-
Modulus of deformation measured by Prima LWD device with a 300 mm diameter plate
- ELWD-Z3 :
-
Modulus of deformation measured by Zorn LWD device with a 300 mm diameter plate
- Dr :
-
Relative density (%)
References
Specifications for Road and Bridge Works of Ministry of Road Transport & Highways (MoRTH), (5th Revision) (2013). Indian Roads Congress and Standard, New Delhi
Quintus VHL, Minchin CRE, Nazarian S, Maser KR, Prowell BD (2009) NDT technology for quality assurance of HMA pavement construction. NCHRP Report 626, Transportation Research Board, Washington, DC. https://doi.org/10.17226/14272
Ebrahimi A, Edil TB (2013) Light-weight deflectometer for mechanistic quality control of base course materials. Proc Inst Civ Eng Geotech Eng 166(5):441–450. https://doi.org/10.1680/geng.11.00011
Elhakim AF, Elbaz K, Amer MI (2014) The use of Lightweight deflectometer for in situ evaluation of sand degree of compaction. HBRC J 10(3):298–330. https://doi.org/10.1016/j.hbrcj.2013.12.003
Petersen DL, Siekmeier JA, Nelson CR, Peterson RL (2006) Intelligent soil compaction—technology results and a roadmap toward widespread use. Transp Res Rec. https://doi.org/10.1177/0361198106197500109
Deng-Fong L, Chi-Chou L, Jyh-Dong L (2006) Factors affecting portable falling weight deflectometer measurements. J Geotech Geoenviron Eng 132(6):804–808. https://doi.org/10.1061/(ASCE)1090-0241(2006)132:6(804)
Fleming PR, Frost M, Lambert J (2007) Review of lightweight deflectometer for routine in situ assessment of pavement material stiffness. Transp Res Rec. https://doi.org/10.3141/2004-09
Mooney MA, Miller PK (2008) Analysis of falling weight deflectometer test based on in-situ stress and strain response. J Geotech Environ Eng 134:684–693. https://doi.org/10.1061/(ASCE)1090-0241(2009)135:2(199)
Vennapusa PKR, White DJ (2009) Comparison of light weight deflectometer measurements for pavement foundation materials. ASTM Int Geotech Test J 32(3):239–251
Chaddock B, Brown A J (1995) Road foundation assessment. In: proceedings of the 4th international symposium unbound aggregates in roads (UNBAR4). Nottingham University, pp 200–208
Borowicka H (1936) Influence of rigidity of a circular foundation slab on the distribution of pressures over a contact surface. In: Proc Intl Conf on Soil Mech and Found Engg, vol 2, Harvard University, Cambridge
Terzaghi K, Peck RB (1967) Soil mechanics in engineering practice, 2nd edn. Wiley, New York, pp 281–283
Fang H-V (1991) Foundation engineering, 2nd edn. Springer Science and Business Media, New York
Das BM (1998) Principles of geotechnical engineering, 4th edn. PWS Publishing Co., Boston
Livneh M, Goldberg Y (2001) Quality assessment during road formation and foundation construction: use of falling-weight deflectometer and light drop weight. Transp Res Rec 1755:69–77. https://doi.org/10.3141/1755-08
Nazzal M, Abu-Farsakh M, Alshibli E, Mohammad L (2007) Evaluating light falling-weight deflectometer device for in-situ measurement of elastic modulus of pavement layers. Transp Res Rec. https://doi.org/10.3141/2016-02
Ryden N, Mooney M (2009) Analysis of surface waves from the light weight deflectometer. Soil Dyn Earthq Eng 29(7):1134–1142. https://doi.org/10.1016/j.soildyn.2009.01.002
Fleming PR (2000) Small-scale dynamic devices for the measurement of elastic stiffness modulus on pavement foundations, vol 3. ASTM International, West Conshohocken, pp 41–58
Van Gurp C, Groenendijk J, Beuving E (2000) Experience with various types of foundation tests. In: Proc. unbound aggregates in road construction—UNBAR5, pp 239–246
Bilodeau JP, Doré G (2014) Stress distribution experienced under a portable light-weight deflectometer loading plate. Int J Pavement Eng 15(6):564–575. https://doi.org/10.1080/10298436.2013.772612
Lenngren C, Lukanen EO (1992) Effects of buffers on falling weight deflectometer loadings and deflections. Transp Res Rec 1355:37–51
Adam D, Kopf F (2002) Metrological and theoretical investigations as a basis for the further development and normative application of the dynamic load plate. Report No. 68, Lecture: fairs in the Geotechnik, Technical University of Braunschweig, Germany. Feb 21–22
Larsen BW, White DJ, Jahren CT (2008) Pilot project to evaluate dynamic cone penetration QA/QC specification for non-granular soil embankment construction. Transp Res Rec 2081:92–100
Zhang J (2010) Evaluation of mechanistic-based compaction measurements for earthwork QC/QA. Graduate Theses and Dissertations. 11547. https://lib.dr.iastate.edu/etd/11547
Dwivedi S, Suman SK (2019) Quality assessment of road shoulders using light weight deflectometer and geogauge. Int J Recent Techn Eng. https://doi.org/10.35940/ijrte.B2649.07821
Bisht S, Dhar S, Hussain M (2017) Performance evaluation of lime stabilized sub-grade soil using light weight deflectometer. In: Indian Geotechnical Conference, 14–16 December GeoNEst, IIT Guwahati, India
Rao C, George V, Shiva Shankar R (2008) PFWD, CBR and DCP Evaluation of Lateritic Subgrades of Dakshina Kannada, India. In: 12th International Conference of International Association for Computer Methods and Advances in Geotechnics (IACMAG), National Institute of Technology Karnataka, Mangalore, India, Goa, India, 4417-4423
Alshibli KA, Abu-Farsakh M, Seyman E (2005) Laboratory evaluation of the geogauge and light falling weight deflectometer as construction control tools. J Mater Civil Eng. https://doi.org/10.1061/(ASCE)0899-1561(2005)17:5(560)
Akmaz E, Ullah S, Tanyu BF, Guler EF (2020) Construction quality control of unbound base course using light weight deflectometer where reclaimed asphalt pavement aggregate is used as an example. Transport Res Rec. https://doi.org/10.1177/0361198120934473
Wright J, Kim SS, Kim B (2020) Stiffness and strength improvement of geosynthetic-reinforced pavement foundation using large-scale wheel test. Infrastructures 5:33. https://doi.org/10.3390/infrastructures5040033
Choi Y, Ahn D, Lee Y, Ahn J (2020) Compaction quality monitoring of open-graded aggregates by light weight deflectometer and soil stiffness gauge. Sustainability 12:2521. https://doi.org/10.3390/su12062521
Barounis N, Smith T (2017) Characterization of in situ soils based on the resilient soil modulus using Light Weight Deflectometer (LWD). In: Alexander GJ, Chin CY (eds) Proc 20th NZGS Geotechnical Symposium, Napier
Umashankar B, Hariprasad C, Kumar GT (2016) Compaction quality control of pavement layers using LWD. J Mater Civil Eng. https://doi.org/10.1061/(ASCE)MT.1943-5533.0001379
Volovski M, Arman M, Labi S (2014) Developing statistical limits for using the light weight deflectometer (LWD) in construction quality assurance. Joint Transport Research Program, West Lafayette, Purdue University. Publication No. FHWA/IN/JTRP-2014/10. https://doi.org/10.5703/1288284315504
Prakash Kumar M, Rakesh K (2014) LWD induced flexible pavement rehabilitation strategies. Lambert Academic Publishing, Saarbrücken
Kim J, Kang HB, Kim D, Park DS, Kim WJ (2007) Evaluation of in situ modulus of compacted subgrades using portable falling weight deflectometer and plate-bearing load test. J Mater Civil Eng. https://doi.org/10.1061/(ASCE)0899-1561(2007)19:6(492)
Kuttah D (2020) Determining the resilient modulus of sandy subgrade using cyclic lightweight deflectometer test. Transp Geotech. https://doi.org/10.1016/j.trgeo.1000482
A Fathi, C Tirado, M Mazari, S Nazarian (2019) Models for estimation of lightweight deflectometer moduli for unbound materials. Geo-Congress GSP 310—ASCE
Senseney CT, Krahenbuhl RA, Mooney MA (2013) Genetic algorithm of optimize layer parameters in light weight deflectometer back calculation. Int J Geomech 13(4):473–476. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000222
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Duddu, S.R., Chennarapu, H. Quality control of compaction with lightweight deflectometer (LWD) device: a state-of-art. Geo-Engineering 13, 6 (2022). https://doi.org/10.1186/s40703-021-00171-2
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DOI: https://doi.org/10.1186/s40703-021-00171-2