Bernard Igbafen Izevbekhai

Construction and Performance of Pervious Concrete Overlay at Minnesota Road Research Project

Portland cement pervious concrete (PCPC) has shown great potential to reduce roadway noise, improve splash and spray, and improve friction as a surface wearing course. A study is under way at Iowa State University and the National Concrete Pavement Technology Center to develop mix designs and procedures for PCPC overlays for highway applications. A report is produced on the construction and performance of a PCPC overlay constructed at the Minnesota Road Research Project low-volume roadway test facility to determine the effectiveness of pervious concrete as an overlay. Issues related to construction of the overlay are described, as are results of field tests to characterize the condition of the pavement 7 months following construction, to determine flow characteristics of the overlay, and to characterize the tire–pavement noise of the overlay. Results of these studies show that effective PCPC overlays can be designed for wearing course applications.

Development and validation of a tenable process for quantifying texture spikiness for pavement noise prediction

In pavement infrastructure, it is important to characterise the surfaces for an effective prediction of noise. One of the major influencing variables, texture orientation, also called spikiness, is a measure of how spiky the surface asperities are. Tyre–pavement interaction noise is associated with mechanisms triggered by micro-, macro- and megatexture. Of the variables within macro-texture range, texture spikiness has gained increased interest by providing explanations for scenarios with similar texture direction and mean profile depth on the same level of distress yet exhibiting very different noise levels. A tool created in this research, ‘PARSER’, facilitated computation of skewness/spikiness statistics. This paper therefore tenably quantifies texture spikiness by the method of skewness of amplitude distribution function. Consequently, a logical quantification of texture spikiness has facilitated a phenomenological noise prediction model. When properly quantified, texture spikiness is an indispensable tyre–pavement interaction variable.

Acoustic enhancement of concrete pavement surface through diamond grinding

Functionality of concrete pavements can be restored through conventional diamond grinding (CDG) that improves ride quality and friction. Recently, an alternative diamond grinding configuration was proposed by the Institute for Safe Quiet and Durable Highway at Purdue University as part of a nationwide interest in quiet pavements. This paper discusses the field-testing of the CDG and alternative (innovative) diamond grinding as well as the pre-existing transverse tined (TT) texture at the MnROAD research facility. Acoustic properties, ride quality and friction performance of the diamond ground surfaces are compared to data obtained in the pre-existing TT surface. The initial performance of the innovative grind over a period of 3 years is also compared to that of the conventional grind and the TT surface. Test results, analysis, merits and demerits of the grinding types are also accentuated.

Comparison of Pavement Texture Measurements from a Three-Dimensional Profiler and a Circular Track Meter at MnROAD Test Facilities

This paper compares pavement texture measurements from a three-dimensional (3-D) line-laser scanner and from a two-dimensional (2-D) spot-laser circular track (CT) meter to determine whether correlations exist between their texture parameters. Measurements with the two devices were taken simultaneously on pavements at the Minnesota Department of Transportation MnROAD test facilities. The 3-D texture heights were decomposed by using a discrete wavelet transform to separate microtexture from macrotexture. Macrotexture parameters from the two devices were analyzed. A linear relationship, with an R2 value of .94, was found between the 2-D mean profile depth and the 3-D digitally simulated mean texture depth. Similarly, the R2 value was .98 between the 2-D root mean square roughness and the 3-D root mean square deviation. These correlations are essential and can be used by road agencies to predict texture indexes between 2-D and 3-D measurements for data comparison or quality assurance when equipment is of different dimensions.

Sustainability of Using Recycled Concrete Aggregates as Coarse Aggregate in Concrete Pavements

Conservation and reuse of resources are important aspects of sustainability. It is common practice in the U.S. to crush old concrete pavements at the end of their service lives into recycled concrete aggregate and then reuse them in the base course of new pavements. It is not, however, common to use the recycled concrete aggregate (RCA) in the new concrete pavement itself. This paper examines the sustainability and, in particular, the economics of using RCA in the construction of new concrete pavements. Life cycle cost analyses were performed for various hypothetical pavement construction scenarios including RCA both in the base and in the concrete layer and compared with conventional options. If RCA is simply substituted for natural aggregate in a concrete mixture, the concrete is likely not to perform as well as a concrete made without RCA. This can be compensated for by decreasing the water–cement ratio and/or increasing the cement content. Despite this fact, the results of the life cycle cost analyses show that it can be very economical to use RCA in new concrete pavement construction. As the natural aggregate used for concrete may be more expensive than the natural aggregate used for base courses, it may make good economic sense to substitute RCA for natural aggregate in concrete. Life cycle analysis also shows that concrete with RCA may have better environmental impact.

Performance of recycled concrete aggregate pavements based on historical condition data

ABSTRACT The principles of sustainability dictate that construction materials should be recycled whenever possible. In the US, it is a common practice to crush old concrete pavements at the end of their service lives into recycled concrete aggregate (RCA) for use in the base course of new pavements but not to use the RCA in the new concrete pavement layer itself. In the 1980s, a number of trial projects were built in the US; however, their performance has never been evaluated quantitatively against that of similar conventional concrete pavements. In this paper, the performance of trial sections built in Minnesota were compared to that of their conventional counterparts. Such a study was necessary to evaluate the sustainability of using RCA in the concrete pavement. Analysis techniques employed included triple exponential smoothing, autoregressive integrated moving average, artificial neural network and Markov models. The mean time to reach a condition requiring a major CPR was found to be 27 years for the RCA pavements and 32 years for the non-RCA pavements. Despite this fact, it is possible to make the use of RCA in new concrete economically viable and sustainable. A lifecycle cost analysis over a 40 year time period showed the pavements with 100% coarse RCA to be cheaper at

Deployment of the Next Generation Concrete Surface in Minnesota

1.10 per m2 compared to the conventional concrete.

Effect of Early Opening to Traffic on Fatigue Damage to Concrete Pavement

Development of a quiet diamond grinding configuration commenced in an initial laboratory effort at Purdue University, followed by research iterations from 2007 to 2010 at the pavement test track research facility (MnROAD) of the Minnesota Department of Transportation (DOT). This paper catalogues the stages in the development and deployment of the Next Generation Concrete Surface (NGCS) from the configuration development at MnROAD, coupled with the simultaneous development of a tire–pavement noise predictive model deployed on Interstate 94 near Saint Cloud, Interstate 35 in Duluth, and Interstate 394 in Minneapolis, Minnesota. NGCS in these projects caused noise reduction of 3 to 6 dB, representing 50% to 75% sound intensity reduction. Diamond grinding was performed on the preexisting textures: burlap drag on Interstate Highway 94 near Saint Cloud, transverse tining on Interstate Highway 35 in Duluth, and Ultra-Thin Bonded Wearing Course (UTBWC) on Interstate 394, Minnesota DOT exceeded the goal of not increasing the pregrind tire–pavement noise level by these rehabilitations. The predictive tire–pavement interaction noise model was validated in these deployments, including on Interstate 394, where the full acoustic benefit of NGCS had been attenuated by the anomalous effect of undulations reminiscent of the previous concrete–UTBWC interface, which had inadvertently conferred a background configuration to the new diamond-ground surface.

Roughness Index Measured with Triple-Point and Line Lasers in Textured and Nontextured Strips

The current methods for determining criteria for opening a roadway to traffic are often overly conservative, causing unnecessary construction delays and user costs. This problem can be explained, in part, by the purely empirical nature of the current methods. These criteria require wait periods after concrete placement or certain levels of compressive or flexural strength, or both, after concrete placement, and specific site conditions are not accounted for. Further, the effect of early traffic-related loads on long-term pavement behavior has not been quantified. In this study, the effect of early opening on pavement damage was reexamined through a laboratory study and analytical modeling. The result was a mechanistic-based procedure for evaluating the effect of early opening to traffic on the accumulation long-term damage; this procedure also accounts for critical factors such as climate, traffic level, and pavement design characteristics. The basis of this method is a modification of the fatigue damage analysis in the Mechanistic–Empirical Pavement Design Guide; this modification enables an analysis of traffic loading on the first 28 days of pavement life. The procedure also enables an update to predictions on the basis of as-built nondestructive testing measurements of the pavement. The output of the analysis is a quantitative damage prediction that allows the road owner to do a cost–benefit analysis of the timing for opening the road on the basis of the specific site and traffic characteristics. The results presented here show how innovated opening criteria based on load restrictions can allow for early opening while mitigating any adverse effect on the long-term pavement performance.

Development of Aggregate Avoidance Index for Evaluating Recycled Aggregate Concrete

Practitioners have often wondered whether, during ride measurement with inertial devices, the motion of the laser through pavement texture introduces nonrepresentative values of international roughness index (IRI), particularly in certain textures. In response to this problem, a special texture study created a nontextured strip by a recession of the middle 4 ft of a texturing broom dragged longitudinally behind the paver. The study measured IRI and other surface properties in adjacent textured and nontextured strips by using a lightweight profiler outfitted with a line laser and a triple laser arranged in tandem. IRI measurements were performed after sufficient concrete strength gain and repeated as soon as the joints were sawn. The same measurements were repeated after the joints were deployed. Results showed a significant difference between the IRI of a textured strip and that of an nontextured strip. Further analysis indicated that, although texture appears to affect IRI, this effect was amplified by the type of laser used, as the triple laser appeared to indicate higher IRIs in comparison with the RoLine laser. Although the RoLine is not a reference profiler for IRI values unaffected by texture, the prevalence of the RoLine and the triple laser in construction acceptance testing is sufficient reason to be concerned about the difference inherent in the obtained results. Chi-square and t-test statistical analysis showed that laser type induced comparable and even higher IRI anomalies than did the experimental drag texture. In addition, the texture-induced IRI anomaly can be minimized by measuring smoothness for acceptance at least 2 weeks after paving.