Durability of P.C. Concrete as Affected by Aggregate Size, Curing and Proportions, R-214, 1968

The durability of concrete is a most important aspect in pavement life. Deterioration of the interstate portland cement concrete pavement has prompted various studies of factors which may contribute to the durability. Studies of cores taken from deteriorated areas indicated that the larger particles of coarse aggregate may contribute greatly to the problem. This indication was mainly due to the analysis of the cracking pattern which showed that most of the cracks passed through the larger aggregates and the larger aggregate particles were more cracked than the smaller particles. The purpose of this project is to determine if the size of the coarse aggregate has a bearing on the durability of freeze and thaw beams. A secondary purpose of this project is to determine what effect the method of curing and proportions have on the durability of freeze and thaw beams.

Improvement of Granular Base Course Materials with Portland Cement, Special Report, HR-99

A highway base course may be defined as a layer of granular material which lies immediately below the wearing surface of a pavement and must possess high resistance to deformation in order to withstand pressures imposed by traffic. A material commonly used for base course construction is crushed limestone. Sources of limestone, acceptable for highway bases in the state of Iowa, occur almost entirely in the Pennsylvanian, Mississippian and Devonian strata. Performance records of the latter two have been quite good, while material from the Pennsylvanian stratum has failed on numerous occasions. The study reported herein is one segment of an extensive research program on compacted crushed limestone used for flexible highway base courses. The primary goals of the total study are: 1. Determination of a suitable and realistic laboratory method of compaction. 2. Effect of gradation, and mineralogy of the fines, on shearing strength. 3. Possible improvement of the shear strength with organic and inorganic chemical stabilization additives. Although the study reported herein deals primarily with the third goal, information gathered from work on the first two was required for this investigation. The primary goal of this study was the evaluation of various factors of stability of three crushed limestones when treated with small amounts of type I Portland cement. Investigation of the untreated materials has indicated that shear strength alone is not the controlling factor for stability of crushed stone bases. Thus the following observations were made in addition to shear strength parameters, to more adequately ascertain the stability of the cement treated materials: 1. Volume change during consolidation and shear testing. 2. Pore pressure during shear. The consolidated-undrained triaxial shear test was used for determination of the above factors.

Performance of Concrete Bridge Deck Overlays, HR-501, 1990

Chloride-ions penetrating into bridge decks and corroding the steel have been a major problem. As the steel corrodes it exerts stresses on the surrounding concrete. When the stresses exceed the strength of the concrete, cracks or delaminations occur. This, of course, causes deterioration and spalling of bridge deck surfaces. Both the Latex and Iowa Method were used to repair bridge decks for this project. The concrete was removed down to the steel and replaced with approximately 1 1/2 inches of low slump or latex modified concrete. The removal of unsound concrete below the top layer of steel was sometimes necessary. The objective of this project was to determine if the bridge overlays would provide a cost effective method of rehabilitation. To do this, unsound and delaminated concrete was removed and replaced by an overlay of low slump or latex modified concrete.

Determination of Asphalt Content and Characteristics of Bituminous Paving Mixtures, MLR-88-11, 1988

Due to the hazardous nature of chemical asphalt extraction agents, nuclear gauges have become an increasingly popular method of determining the asphalt content of a bituminous mix. This report details the results of comparisons made between intended, tank stick, extracted, and nuclear asphalt content determinations. A total of 315 sets of comparisons were made on samples that represented 110 individual mix designs and 99 paving projects. All samples were taken from 1987 construction projects. In addition to the comparisons made, seventeen asphalt cement samples were recovered for determination of penetration and viscosity. Results were compared to similar tests performed on the asphalt assurance samples in an attempt to determine the amount of asphalt hardening that can be expected due to the hot mix process. Conclusions of the report are: 1. Compared to the reflux extraction procedure, nuclear asphalt content gauges determine asphalt content of bituminous mixes with much greater accuracy and comparable precision. 2. As a means for determining asphalt content, the nuclear procedure should be used as an alternate to chemical extractions whenever possible. 3. Based on penetration and viscosity results, softer grade asphalts undergo a greater degree 'of hardening due to hot mix processing than do harder grades, and asphalt viscosity changes caused by the mixing process are subject to much more variability than are changes in penetration. 4. Based on changes in penetration and viscosity, the Thin Film Oven Test provides a reasonable means of estimating how much asphalt hardening can be anticipated due to exposure to the hot mix processing environment.

How important are interview methods and questionnaire designs in research on self-reported juvenile delinquency? An experimental comparison of internet vs. paper-and-pencil questionnaires and different definitions of the reference period

There has been relatively little change over recent decades in the methods used in research on self-reported delinquency. Face-to-face interviews and selfadministered interviews in the classroom are still the predominant alternatives envisaged. New methods have been brought into the picture by recent computer technology, the Internet, and an increasing availability of computer equipment and Internet access in schools. In the autumn of 2004, a controlled experiment was conducted with 1,203 students in Lausanne (Switzerland), where "paper-and-pencil" questionnaires were compared with computer-assisted interviews through the Internet. The experiment included a test of two different definitions of the (same) reference period. After the introductory question ("Did you ever..."), students were asked how many times they had done it (or experienced it), if ever, "over the last 12 months" or "since the October 2003 vacation". Few significant differences were found between the results obtained by the two methods and for the two definitions of the reference period, in the answers concerning victimisation, self-reported delinquency, drug use, failure to respond (missing data). Students were found to be more motivated to respond through the Internet, take less time for filling out the questionnaire, and were apparently more confident of privacy, while the school principals were less reluctant to allow classes to be interviewed through the Internet. The Internet method also involves considerable cost reductions, which is a critical advantage if self-reported delinquency surveys are to become a routinely applied method of evaluation, particularly so in countries with limited resources. On balance, the Internet may be instrumental in making research on self-reported delinquency far more feasible in situations where limited resources so far have prevented its implementation.

Protéinurie orthostatique et phénomène de compression de la veine rénale gauche (nutcracker syndrome) [Orthostatic proteinuria and compression of the left renal vein (nutcracker syndrome)]

INTRODUCTION: The pathogenic mechanism of orthostatic proteinuria has not yet been clearly established. OBSERVATION: In a tall, thin, 21 year-old man, isolated proteinuria was discovered during an urological control conducted one year after a bilateral orchidopexy following left testicular torsion. Proteinuria was orthostatic. Doppler examination of the kidney revealed an entrapment of the left renal vein (nutcracker phenomenon-NCP). COMMENTS: An NCP was diagnosed in a young patient presenting with orthostatic proteinuria. By provoking modifications in intraglomerular haemodynamics, the NCP may, in nearly half of the cases, be at the origin of orthostatic proteinuria. Doppler examination is the diagnostic method of choice in the screening for NCP.

Sensitivity to Change of the Ultrasound synovitis SONAR Score in RA Patients: Results of the Scqm Cohort

Background/Purpose: Since the end of 2009, an ultrasound scoring call SONAR has been implemented for RA patients as a routine tool in the SCQM registry (Swiss Clinical Quality Management registry for rheumatic diseases). A cross-sectional evaluation of patients with active disease and clinical remission according to the DAS28ESR and the novel ACR/EULAR remission criteria from 2010 clearly indicated a good correlational external validity of synovial pathologies with clinical disease activity in RA (2012 EULAR meeting. Objective: of this study was to evaluate the sensitivity to change of B-mode and Power-Doppler scores in a longitudinal perspective along with the changes in DAS28ESR in two consecutive visits among the patients included in the SCQM registry Methods: All patients who had at least two SONAR scores and simultaneous DAS28ESR evaluations between December 2009 and June 2012 were included in this study. The data came from 20 different operators working mostly in hospitals but also in private practices, who had received a previous teaching over 3 days in a reference center. The SONAR score includes a semi-quantitative B mode and Power-Doppler evaluation of 22 joints from 0 to 3, maximum 66 points for each score. The selection of these 22 joints was done in analogy to a 28 joint count and further restricted to joint regions with published standard ultrasound images. Both elbows and wrist joints were dynamically scanned from the dorsal and the knee joints from a longitudinal suprapatellar view in flexion and in joint extension. The bilateral evaluation of the second to fifth metacarpophalangeal and proximal interphalangeal joints was done from a palmar view in full extension, and the Power-Doppler scoring from a dorsal view with hand and finger position in best relaxation. Results: From the 657 RA patients with at least one score performed, 128 RA patients with 2 or more consultations of DAS28ESR, and a complete SONAR data set could be included. The mean (SD) time between the two evaluations was 9.6 months (54). The mean (SD) DAS28ESR was: 3.5 (1.3) at the first visit and was significantly lower (mean 3.0, SD.2.0, p:_0.0001) at the second visit. The mean (SD) of the total B mode was 12 (9.5) at baseline and 9.6 (7.6) at follow-up (p_0.0004). The Power-Doppler score at entry was 2.9 (5.7) and 1.9 (3.6), at the second visit, p _0.0001. The Pearson r correlation between change in DAS28ESR and the B mode was 0.44 (95% CI: 0.29, 0.57, p_ 0.0001),and 0.35 (95% CI: 0.16, 0.50, p _ 0.0002) for the Power-Doppler score,. Clinical relevant change in DAS (_1.1) was associated with a change of total B mode score _3 in 23/32 patients and a change a Doppler score _0.5 in 19/26. Conclusion: This study confirms that the SONAR score is sensitive to change and provides a complementary method of assessing RA disease activity to the DAS that could be very useful in daily practice.