Comparison of the Pavement Layers Thickness Measured by Georadar and Conventional Methods – Examples From Croatia

Abstract

Thickness of the pavement structure layers represents an important data for the implementation into the database of roads already constructed, during the pavement strengthening design, particularly if the appraisal of the bearing capacity of the pavement structure is done by means of the Falling Weight Deflectometer, during reconstruction of pavements or during control of the newly constructed roads. If reconstruction is carried out by procedures of recycling of the existing pavement the details about the thickness of asphalt layers are important not only when determining the depth of the intervention but also when designing asphalt mixture. During quality control of the newly constructed road sections the Ground Penetrating Radar (GPR, georadar) can be used as the instrument for fast and efficient determination of the thickness of layers. Measuring is done at speeds that approx correspond to the speeds of traffic flow, so that disturbance of traffic is minimum, whereby the safety of participants in traffic and measuring personnel is increased. The paper presents several examples of determining the thickness of layers of road pavement structures by the non-destructive GPR method. The obtained results were compared to conventional methods of determining thicknesses that are used in Croatia, i.e. coring or data obtained by surveying methods during construction of the pavement structural layers. Measurements were done on completely new and existing roads of different age having the asphalt pavement.

Spatial Representation of GPR Data—Accuracy of Asphalt Layers Thickness Mapping

“…Analysis of the GPR data collected from different sites showed that thickness error increases with pavement age-4.4% error for 0-to 5-year-old pavements and 5.8% error for pavements older than 20 years having surfaces older than 10 years [14]. In Croatia, studies have been conducted on motorways, regional and county roads and on runways [18,19]. The error for new pavements of motorways was mostly less than 10% and varied from 0.16% to 12.32% [18].…”

“…In Croatia, studies have been conducted on motorways, regional and county roads and on runways [18,19]. The error for new pavements of motorways was mostly less than 10% and varied from 0.16% to 12.32% [18]. For regional and county roads that have been in service for years, the error ranges from 6.70% to 14.83% [18].…”

Application of GPR and FWD in Assessing Pavement Bearing Capacity

“…EM waves partly reflect and partly pass through layers of materials with different EM characteristics. A part of energy that reflects at layers interface is receive by GPR system and displayed as a plot of amplitude (voltage) and time necessary for its return to antenna (Figure 1, right) [2].…”

“…Evaluation studies carried out in the last 20 years show that deviations between GPR and core thickness results of newly constructed pavement range from 2% to 5% of total thickness [1] and for old pavements are mostly less than 10% [2]. Based on this it can be conclude that GPR is suitable non-destructive technique, which can replace coring.…”

Methodology of Nondestructive Identification of Defective Concrete Zones in Unilaterally Accessible Massive Members

“…Nondestructive acoustic techniques, especially the state-of-the-art impulse response technique (ASTM C1740-10 2010) and ultrasonic tomography , increasingly and often used today to diagnose building structures, can be helpful in this regard (Schickert 2005;Beutel et al 2008;Maksymowicz et al 2011;Zwolski, Bień 2011;Goszczyńska et al 2012;Leibbrandt et al 2012;Ožbolt et al 2012).…”