Specification Limits and Pay Adjustment for Longitudinal Joint Density of Asphalt Pavements: Case Study in New Jersey

Abstract

This paper summarizes a case study on developing specification limits and pay adjustments for the longitudinal joint density of asphalt pavements. The existing joint density specifications used by various agencies first were reviewed for the minimum joint density requirements and the corresponding pay adjustments. Laboratory tests were conducted to measure air voids of field cores taken from selected field projects with the saturated surface dry method (AASHTO T 166) and the automatic vacuum-sealing method (AASHTO T 331). Permeability measurements were conducted with a falling-head permeability device. The air voids at the joint were found to be 1.5% to 2% greater than the air voids at the mats adjacent to the joint. For conditions specific to New Jersey, individual testing of the theoretical maximum density of the cores taken at the joint is recommended because of the existence of joint adhesive. The upper limits for air voids at the longitudinal joint are recommended to be 9% for stone matrix asphalt and 10% for hot-mix asphalt, on the basis of the permeability criterion of 150 × 10−5 cm/s reported in previous studies. Furthermore, alternative pay equations for air voids at the longitudinal joint were proposed, with different triggers for retest and for rejectable quality level. A SpecRisk analysis was conducted to confirm that the effective acceptable quality level coincided with the stated acceptable quality level and that the acceptance procedures properly awarded 100% payment at the stated acceptable quality level. The study led to a draft quality assurance specification for longitudinal joint density that was proposed for future implementation.

Comprehensive Analysis of Steel Slag as Aggregate for Road Construction: Experimental Testing and Environmental Impact Assessment

“…In traditional asphalt mixture gradation designs, air voids in the asphalt mixture are the most important indexes of volumetric properties; they can also affect the performance of an asphalt pavement. Several studies have been conducted to determine the effect of air voids on the performance characteristics of asphalt mixtures, including fatigue cracking and rutting [63]. These reports suggest that the road service life decreases by approximately one year for every 1% increase in the air void content.…”

Quality Control of Asphalt Pavement Field Compaction Using Field-Measured Pavement Permeability

“…Major findings by Fleckenstein et al (2002) and Mallick & Daniel (2006) indicate that although, the joint maker technique and adhesive treated joints had the lowest densities of all the joint improvement methods studied; they had lower permeability values and the best performance under long-term performance study compared to joint constructed using the conventional methods. Similar findings by Wang et al (2016) and Williams (2011) suggested that while asphalt pavement longitudinal joint treated with the joint stabilizer using polymerized emulsion products had the least density; it ironically had the best performance. Thus, one would argue that the ability to limit the intrusion of water into the body of the asphalt concrete could lead to a better performing and more durable pavement system.…”

Use of grid reinforcement in HMA overlays – A Texas field case study of highway US 59 in Atlanta District

“…By default, there is a theoretical notion that the application of grid reinforcements inherently reduces and weakens the interlayer bonding strength of the HMA overlay, which may not be the case. However, most of the literature reviewed provided shear-bond strength data on un-reinforced HMA overlays, mostly based on laboratory prepared-samples [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Based on field core testing, Wilson et al [17] measured a shearbond strength range of 15-95 psi with satisfactory in-service (field) interlayer bonding performance [11].…”

“…From testing both field cores and laboratory prepared-samples with different grid-reinforcement materials, Walubita et al [15] recorded interlayer shear-bond strengths varying from 33 to 175 psi. Overall, shearbond strength values ranging from as low as 15 psi to as high as 217 psi were reviewed in the literature, mostly for un-reinforced HMA and subjected to varying laboratory test methods/conditions [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Furthermore, different institutions, states, and countries seem to have different criteria for characterizing and quantifying the interlayer bond strength in HMA; ranging from a tolerable 40 psi [17] to a more stringent shear-bond strength value of 100 psi [18,19].…”