Determination of Sample Size and Influencing Factors to Characterize Faulting in Jointed Concrete Pavements

2021 ◽  
pp. 036119812199670
Author(s):  
Ruohan Li ◽  
Jorge A. Prozzi
Keyword(s):  
Sample Size ◽  
Plain Concrete ◽  
Concrete Pavements ◽  
Portland Cement Concrete ◽  
Federal Highway ◽  
Significant Difference ◽  
Jointed Concrete Pavement ◽  
Functional Classes ◽  
High Precipitation ◽  
Departments Of Transportation

The objective of this study is to evaluate the field variability of jointed concrete pavement (JCP) faulting and its effects on pavement performance. The standard deviation of faulting along both the longitudinal and transverse directions are calculated. Based on these, the overall variability is determined, and the required sample sizes needed for a given precision at a certain confidence level are calculated and presented. This calculation is very important as state departments of transportation are required to report faulting every 0.1 mi to the Federal Highway Administration as required by the 2015 FAST Act. On average, twice the number of measurements are needed on jointed reinforced concrete pavements (JRCP) to achieve the same confidence and precision as on jointed plain concrete pavements (JPCP). For example, a sample size of 13 is needed to achieve a 95% confidence interval with a precision of 1.0 mm for average faulting of JPCP, while 26 measurements are required for JRCP ones. Average faulting was found to correlate with several climatic, structural, and traffic variables, while no significant difference was found between edge and outer wheelpath measurements. The application of Portland cement concrete overlay and the use of dowel bars (rather than aggregate interlock) are found to significantly reduce faulting. Older sections located on higher functional classes, and in regions of high precipitation or where the daily temperature change is larger, tend to have higher faulting, and might require larger samples sizes as compared with the rest when faulting surveys are to be conducted.

An Area-Based Faulting Measurement Method Using Three-Dimensional Pavement Data

2018 ◽  
Vol 2672 (40) ◽  
pp. 41-49 ◽  
Author(s):  
Georgene M. Geary ◽  
Yichang (James) Tsai ◽  
Yiching Wu
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Field Tests ◽  
Automatic Testing ◽  
Specific Method ◽  
Concrete Pavements ◽  
Federal Highway ◽  
Manual Testing ◽  
The Impact ◽  
Departments Of Transportation

Faulting is one of the three performance measures recognized by the Code of Federal Regulations (CFR) for jointed concrete pavements. U.S. Federal Highway Administration rules developed for the CFR require the state Departments of Transportation to use the AASHTO Standard R 36, Standard Method for Evaluating Faulting of Concrete Pavements, for measurement of faulting. R 36 allows both manual testing using a faultmeter and automatic testing using a high-speed inertial profiler (HSIP). There is a concern in the literature that the HSIP methods are not accurate enough for network level testing of faulting. Recent studies have also shown that three-dimensional (3-D) laser technology is showing promise for providing more accurate faulting measurements. Still, there currently is not a specific method in R 36 that utilizes 3-D data for gathering faulting measurements. This paper proposes a new method that takes full advantage of the full-coverage capabilities of 3-D to measure faulting more accurately and consistently. This method uses the comparison of smoothed areas on both sides of a joint instead of a single longitudinal profile to measure elevation differences. Field tests were performed to compare the 3-D method with manual readings taken with a Georgia faultmeter on two sections of interstate in Georgia. In addition, the impact of various footprints and measuring locations of faulting measurements using this 3-D technology were quantitatively evaluated using the proposed method. Based on this case study the new proposed 3-D method appears to be appropriate to be considered to be added as a 3-D automatic method in AASHTO R 36.

Functional distress modelling in Portland cement concrete pavements

2003 ◽  
Vol 30 (4) ◽  
pp. 696-703
Author(s):  
Hernán de Solminihac ◽  
Marcelo G Bustos ◽  
Aníbal L Altamira ◽  
Juan Pablo Covarrubias
Keyword(s):  
Construction Material ◽  
Plain Concrete ◽  
Service Level ◽  
Pavement Management ◽  
Pavement Performance ◽  
Ride Quality ◽  
Concrete Pavements ◽  
Road Maintenance ◽  
Portland Cement Concrete ◽  
Traffic Loads

Concrete is widely used as a construction material in pavements by public and private agencies that administer highway networks because of its high durability and capacity to resist large traffic loads and very rigorous climates. Nevertheless, these agencies have to estimate the evolution of pavement performance to plan and optimize the application of adequate maintenance activities, allowing the pavement to be maintained at an optimum service level throughout its lifetime. Predictive distress models of the incremental type, that is, models capable of predicting annual increments of different distress indicators in the pavement, could be very useful tools in the implementation of maintenance plans, with minimal need for previous data, especially with regard to information on cumulative traffic loads. This paper offers incremental models for distress prediction in jointed plain concrete pavements, related to joint problems such as faulting and spalling, which clearly affect the pavement ride quality. The equations obtained allow for not only the calculation of distress predictions in analyzing road maintenance policies, but also the adjustment of the original designs of these pavements, to minimize the occurrence and magnitude of distress problems.Key words: concrete pavements, distress models, pavement performance, pavement management systems.

A Tale of Two Pavements: Forensic Investigation of an Unbonded Concrete Overlay and a Concrete Pavement Reconstruction on I-40 near Flagstaff, Arizona

2018 ◽  
Vol 2672 (40) ◽  
pp. 264-274 ◽  
Author(s):  
Thomas J. Van Dam ◽  
Nicole Dufalla ◽  
Linda Pierce
Keyword(s):  
Good Condition ◽  
Plain Concrete ◽  
Concrete Pavement ◽  
Petrographic Analysis ◽  
Concrete Pavements ◽  
Portland Cement Concrete ◽  
Deicing Chemicals ◽  
Concrete Joints ◽  
High Level ◽  
Aggregate Base

In 1990, the Arizona Department of Transportation (ADOT) constructed a Specific Pavement Studies (SPS)-6 experiment on eastbound Interstate 40 (I-40) east of Flagstaff, AZ, as part of the Long-Term Pavement Performance Program. The SPS-6 experiment was designed to evaluate treatment and rehabilitation options for an existing concrete pavement. Nineteen sections were constructed, one of which was a 10 in. thick unbonded concrete overlay (UBCOL). Additionally, ADOT planned to construct an 11 in. unbonded portland cement concrete (PCC) overlay on the adjacent I-40 westbound to investigate benefits of additional concrete thickness. The eastbound unbonded PCC overlay has significantly outperformed all other pavement sections and remains in good condition after 27 years of service. However, the westbound PCC section is severely distressed and in need of immediate rehabilitation. An investigation was conducted to evaluate why two similar unbonded PCC overlays performed with vastly different results. It was found that the westbound “unbonded PCC overlay” was not an overlay after all, but instead a 12 to 13 in.thick jointed plain concrete pavement (JPCP). The high level of distress in the westbound JPCP is likely related to the presence of a weak subgrade that infiltrated the aggregate base. Additionally, during coring, water filled the core holes suggesting that the subgrade in the westbound direction was saturated. Further, petrographic analysis indicated deicing chemicals contributed to corrosion of the dowel bars and deterioration of the concrete joints. This investigation demonstrates some advantages for using unbonded overlays as rehabilitation alternatives for existing concrete pavements.

Transverse Cracking Distress in Long-Term Pavement Performance Jointed Concrete Pavement Sections

1998 ◽  
Vol 1629 (1) ◽  
pp. 6-12 ◽  
Author(s):  
Eric D. Moody
Keyword(s):  
Prediction Models ◽  
Plain Concrete ◽  
Pavement Performance ◽  
Complete Analysis ◽  
Concrete Pavements ◽  
Joint Spacing ◽  
Transverse Cracking ◽  
Design Variables ◽  
Jointed Concrete Pavement

Transverse cracking is one of the more common distress manifestations in jointed concrete pavements. While the extent of transverse cracking is largely related to the specified joint spacing, there are several other primary design variables and distress mechanisms that can cause varying degrees of transverse cracking. These primary mechanisms and their associated variables are well-documented in the literature. However, all of these mechanisms often work on the pavement simultaneously over many years and, as a result, it has historically been difficult to calibrate prediction models with field data. The Strategic Highway Research Program’s Long-Term Pavement Performance (LTPP) program has collected a significant amount of condition survey data on more than 110 jointed plain concrete pavements (JPCP) and 65 jointed reinforced concrete pavements (JRCP) throughout North America over the last 7 years. The occurrence of transverse cracking in these sections is one of the principal distresses documented in the condition surveys and therefore provides an excellent data source for examining the relationships between the various primary distress mechanisms and the actual occurrence of distress in the field. Although it is premature to develop or calibrate purely “mechanistic” models based on the LTPP data, enough data have been collected to begin analyzing this distress and its association with the numerous prediction variables in the LTPP database. A complete analysis of the transverse cracking that has occurred in these LTPP test sections, along with their respective relationships with the primary prediction variables found in the primary distress mechanisms, is provided.

Performance evaluation of jointed plain concrete pavements with sealed and unsealed joints in North Texas

2019 ◽  
Vol 46 (7) ◽  
pp. 601-608
Author(s):  
Mena I. Souliman ◽  
Ashish Tripathi ◽  
Lubinda F. Walubita ◽  
Mayzan M. Isied
Keyword(s):  
Field Performance ◽  
Plain Concrete ◽  
Water Infiltration ◽  
Concrete Pavements ◽  
North Texas ◽  
Pavement Distress ◽  
Initial Cost ◽  
Additional Costs ◽  
Cost Of Construction

Joint sealing in jointed plain concrete pavement (JPCP) has been practiced throughout the world for many years as it improves the performance of concrete pavements. The infiltration of water is a common problem in concrete pavements and often increases distresses, such as faulting and pumping. For this reason, sealing the joints can help reduce water infiltration. Additionally, the infiltration of sand and small stones, aggregates, or debris into the joints can also be prevented, consequently reducing joint spalling in concrete pavements. However, it is also reported that joint sealing increases the initial cost of construction, especially if the joints need to be resealed, which leads to some additional costs. In this study, the pavement distress data was collected from the long-term pavement performance (LTPP) database for all the JPCPs sections in North Texas. The study illustrates the relative field performance in terms of spalling, faulting, roughness, and deflections of JPCP sections for both sealed and unsealed LTPP sections of North Texas.

scholarly journals Waste Tire Particles and Gamma Radiation as Modifiers of the Mechanical Properties of Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Eduardo Sadot Herrera-Sosa ◽  
Gonzalo Martínez-Barrera ◽  
Carlos Barrera-Díaz ◽  
Epifanio Cruz-Zaragoza
Keyword(s):  
Mechanical Properties ◽  
Gamma Radiation ◽  
Chemical Properties ◽  
Plain Concrete ◽  
Cement Matrix ◽  
Portland Cement Concrete ◽  
High Concentration ◽  
Good Tool ◽  
Waste Tire ◽  
Physical And Chemical

In polymer reinforced concrete, the Young’s modulus of both polymers and cement matrix is responsible for the detrimental properties of the concrete, including compressive and tensile strength, as well as stiffness. A novel methodology for solving such problems is based on use of ionizing radiation, which has proven to be a good tool for improvement on physical and chemical properties of several materials including polymers, ceramics, and composites. In this work, particles of 0.85 mm and 2.80 mm obtained from waste tire were submitted at 250 kGy of gamma radiation in order to modify their physicochemical properties and then used as reinforcement in Portland cement concrete for improving mechanical properties. The results show diminution on mechanical properties in both kinds of concrete without (or with) irradiated tire particles with respect to plain concrete. Nevertheless such diminutions (from 2 to 16%) are compensated with the use of high concentration of waste tire particles (30%), which ensures that the concrete will not significantly increase the cost.

New Long-Life Concrete Pavements in the Czech Republic

2021 ◽  
Author(s):  
Bohuslav Slánský ◽  
Vit Šmilauer ◽  
Jiří Hlavatý ◽  
Richard Dvořák
Keyword(s):  
Isothermal Calorimetry ◽  
Coupled Model ◽  
Plain Concrete ◽  
Pilot Project ◽  
Economic Benefits ◽  
Concrete Pavement ◽  
Technical Solution ◽  
Concrete Pavements ◽  
Hydration Kinetics

A jointed plain concrete pavement represents a reliable, historically proven technical solution for highly loaded roads, highways, airports and other industrial surfaces. Excellent resistance to permanent deformations (rutting) and also durability and maintenance costs play key roles in assessing the economic benefits, rehabilitation plans, traffic closures, consumption and recycling of materials. In the history of concrete pavement construction, slow-to-normal hardening Portland cement was used in Czechoslovakia during the 1970s-1980s. The pavements are being replaced after 40-50 years of service, mostly due to vertical slab displacements due to missing dowel bars. However, pavements built after 1996 used rapid hardening cements, resulting in long-term surface cracking and decreased durability. In order to build durable concrete pavements, slower hardening slag-blended binders were designed and tested in the restrained ring shrinkage test and in isothermal calorimetry. Corresponding concretes were tested mainly for the compressive/tensile strength evolution and deicing salt-frost scaling to meet current specifications. The pilot project was executed on a 14 km highway, where a unique temperature-strain monitoring system was installed to provide long-term data from the concrete pavement. A thermo-mechanical coupled model served for data validation, showing a beneficial role of slower hydration kinetics. Continuous monitoring interim results at 24 months have revealed small curling induced by drying and the overall small differential shrinkage of the slab.

Homeopathy: statistical significance versus the sample size in experiments with Toxoplasma gondii

2021 ◽  
Vol 10 (36) ◽  
pp. 115-118
Author(s):  
Érika Cristina Ferreira ◽  
Paula Fernanda Massini ◽  
Caroline Felicio Braga ◽  
Ricardo Nascimento Drozino ◽  
Neide Martins Moreira ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Sample Size ◽  
Biological Effects ◽  
Statistical Significance ◽  
Rare Event ◽  
Public Health Problem ◽  
Control Group ◽  
Bootstrap Analysis ◽  
Significant Difference ◽  
The World

Introduction: Toxoplasmosis is a zoonosis that represents a serious public health problem, caused by Toxoplasma gondii, which affects 20-90% of the world human population [1,2]. It is a serious problem especially when considering the congenital transmission due to congenital sequels. Treatment with highly diluted substances is one of the alternative/complementary medicines most employed in the world [3,4]. The current ethical rules regarding the number of animals used in animal experimental protocols with the use of more conservative statistical methods [5] can not enhance the biological effects of highly diluted substances observed by the experience of the researcher. Aim: To evaluate the minimum number of animals per group to achieve a significant difference among the groups of animals treated with biotherapic T. gondii and infected with the protozoan regarding the number of cysts observed in the brain. Material and methods: A blind randomized controlled trial was performed using eleven Swiss male mice, aged 57 days, divided into two groups: BIOT-200DH - treated with biotherapic (n=6) and CONTROL - treated with hydroalcoholic solution 7% (n=7).The animals of the group BIOT-200DH were treated for 3 consecutive days in a single dose 0.1ml/dose/day. The animals of BIOT – 200DH group were orally infected with 20 cysts of ME49-T. gondii. The animals of the control group were treated with cereal alcohol 7% (n=7) for 3 consecutive days and then were infected with 20 cysts of ME49 -T. gondii orally. The biotherapic 200DH T. gondii was prepared with homogenized mouse brain, with 20 cysts of T. gondii / 100μL according to the Brazilian Homeopathic Pharmacopoeia [6] in laminar flow. After 60 days post-infection the animals were killed in a chamber saturated with halothane, the brains were homogenized and resuspended in 1 ml of saline solution. Cysts were counted in 25 ml of this suspension, covered with a 24x24 mm coverglass, examined in its full length. This study was approved by the Ethics Committee for animal experimentation of the UEM - Protocol 036/2009. The data were compared using the tests Mann Whitney and Bootstrap [7] with the statistical software BioStat 5.0. Results and discussion: There was no significant difference when analyzed with the Mann-Whitney, even multiplying the "n" ten times (p=0.0618). The number of cysts observed in BIOT 200DH group was 4.5 ± 3.3 and 12.8 ± 9.7 in the CONTROL group. Table 1 shows the results obtained using the bootstrap analysis for each data changed from 2n until 2n+5, and their respective p-values. With the inclusion of more elements in the different groups, tested one by one, randomly, increasing gradually the samples, we observed the sample size needed to statistically confirm the results seen experimentally. Using 17 mice in group BIOT 200DH and 19 in the CONTROL group we have already observed statistical significance. This result suggests that experiments involving highly diluted substances and infection of mice with T. gondii should work with experimental groups with 17 animals at least. Despite the current and relevant ethical discussions about the number of animals used for experimental procedures the number of animals involved in each experiment must meet the characteristics of each item to be studied. In the case of experiments involving highly diluted substances, experimental animal models are still rudimentary and the biological effects observed appear to be also individualized, as described in literature for homeopathy [8]. The fact that the statistical significance was achieved by increasing the sample observed in this trial, tell us about a rare event, with a strong individual behavior, difficult to demonstrate in a result set, treated simply with a comparison of means or medians. Conclusion: Bootstrap seems to be an interesting methodology for the analysis of data obtained from experiments with highly diluted substances. Experiments involving highly diluted substances and infection of mice with T. gondii should be better work with experimental groups using 17 animals at least.

Measuring As-Constructed Smoothness of Portland Cement Concrete Pavements with Lightweight Profilometers

2001 ◽  
Vol 1764 (1) ◽  
pp. 189-200
Author(s):  
Mahmuda Akhter ◽  
Mustaque Hossain ◽  
Jeffrey Hancock ◽  
John Boyer ◽  
William J. Parcells
Keyword(s):  
Portland Cement ◽  
Concrete Pavements ◽  
Portland Cement Concrete ◽  
Cement Concrete
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