Durability Assessment of ETICS: Comparative Evaluation of Different Insulating Materials

The External Thermal Insulation Composite System (ETICS) is a common cladding technology that is widely used thanks to its well-known advantages. Despite previous studies dealing with ETICS durability in real-building case studies or involving accelerated ageing tests in climatic chambers, little progress has been made in the knowledge of the long-term durability of the system. In order to realize optimized maintenance plans for this component, the durability of the whole system, and of the most-used insulating materials for the ETICS (i.e., cork, polyurethane, rock wool, glass wool, grey EPS, and fiberfill wood), has been investigated. Based on previous experiments on ageing cycles, different climatic chambers were used to accelerate performance decay by simulating natural outdoor exposure in order to assess different physical and thermal characteristics (thermal transmittance, decrement factor, time shift, water absorption, thermal resistance, and conductivity). Recorded trends show that materials with lower thermal conductivity exhibit lower performance decay, and vice versa. The durability of the ETICS with different insulating materials (as the only variable in the different samples) was evaluated in order to quantify service life and then correctly plan maintenance interventions. Life-cycle assessment must take into account service life and durability for each material of the system. A higher durability of insulating materials allows for the execution of less maintenance interventions, with the loss of less performance over time. This study shows the physical and thermal behavior of the ETICS during its service life, comparing the differences induced by the most-used insulating materials. As a result of accelerated ageing cycles, the analyzed ETICS reveals a low grade of decay and measured performances show little degradation; for thermal conductivity, differences between the measured and the declared conductivities by technical datasheet were observed.

Effects of Actual Marine Atmospheric Pre-Corrosion and Pre-Fatigue on the Fatigue Property of 7085 Aluminum Alloy

Effects of actual marine atmospheric precorrosion and prefatigue on the fatigue property of 7085-T7452 aluminum alloy were investigated by using the methods of marine atmospheric outdoor exposure tests and constant amplitude axial fatigue tests. Marine atmospheric corrosion morphologies, fatigue life, and fatigue fractography were analyzed. After three months of outdoor exposure, both pitting corrosion and intergranular corrosion (IGC) occurred, while the latter was the dominant marine atmospheric corrosion mode. Marine atmospheric precorrosion could result in a dramatical decrease in the fatigue life of the as-received 7085-T7452 aluminum alloy, while selective prefatigue can improve the total fatigue life of the precorroded specimen. The mechanism of the actual marine atmospheric corrosion and its effects on the fatigue life of the 7085-T7452 aluminum alloy were also discussed.

Long-term alkali-silica mitigation of high-alkali concrete with cement replacements

The impact of high-alkali Portland cements on the prescribed level of supplementary cementitious materials required in the Canadian standard for akali-silica reaction mitigation was evaluated. Based on the results, for concretes containing aggregates exhibiting moderate reactivity, the maximum allowable cement alkali limit was raised from 1.00% to 1.15%. For all levels of aggregate reactivity, cement alkali contents could be allowed up to 1.25% provided the recommended level of mitigation by supplementary cementitious materials was increased. In the initial laboratory study, mortar bars and concrete prisms were cast and monitored using two different reactive aggregates and recommended levels of fly ash and slag. For the concrete prism tests, the alkali contents of the cements were increased to 1.25%, as per the standard, or were increased by 0.25%. Instrumented outdoor exposure concrete blocks, along with additional concrete prisms stored at different temperatures, were cast from numerous mixtures made with cement alkali equivalents ranging up to 1.22%. This paper report on the long-term performance of the prisms and concrete blocks after 12 and 27 years. The performance of the outdoor blocks is also compared to predicted performance based on the accelerated mortar bar and concrete prism test results.

1394. Autochthonous Leprosy in Missouri

Background Introduction: Leprosy (Hansen’s disease) is a chronic granulomatous infection of the skin/peripheral nerves caused by Mycobacterium leprae. Of 216 new cases reported in the US in 2019, 70% were in FL, LA, TX, HI, CA, GA and NY. Leprosy is considered a zoonosis in the southern US with the nine-banded armadillo as a reservoir. There have been no reported autochthonous leprosy cases in Missouri. Methods Case: 55 y/o previously healthy male noted a new rash on his arm 2 years ago. Over time it spread to his extremities/torso. Skin biopsy showed a granulomatous infiltrate, suspected granuloma annulare, but it progressed despite appropriate therapy. He noted progressive numbness of the affected areas of skin and several regional nerve distributions. In the weeks prior to his initial visit he noted facial swelling, eyelid and ear induration, worsening fatigue, diffuse arthralgia, and some vision changes. His travel history is limited to Canada, Colorado and a brief vacation to the Texas/Mexico border (no notable outdoor exposure during the latter trip; no travel outside the country). He lives in rural Missouri where he is exposed to armadillos. His dogs frequently kill them and often bring them into the yard, rolling around on/in the dead carcasses which he disposes of. He typically wears gloves when handling them and has never consumed them. On exam he had diffuse purplish-red nummular infiltrated anesthetic papules and plaques diffusely distributed over the trunk and extremities. Distinct left ulnar neuropathy was noted. He exhibited leonine facies and infiltration of the bilateral helices. Repeat biopsy showed a granulomatous infiltrate with abundant acid-fast bacilli. DNA sequencing confirmed M. leprae. He was preventatively treated with prednisone and methotrexate to minimize immune reaction, and two weeks later began a regimen of monthly rifampin, minocycline, and moxifloxacin with an anticipated duration of 24 months. Results Diagnosis lepromatous leprosy with pre-treatment immune reaction. This is potentially the first case of autochthonous leprosy in Missouri. Providers should include Hansen’s disease in the differential diagnosis of patients with dermal eruption and cutaneous neurological symptoms to avoid delays in diagnosis/care. Disclosures All Authors: No reported disclosures

Considerations for Stable Isotope Analysis of Human Hair

Stable isotope analysis of postmortem hair is performed in order to make inferences about an individual’s diet and geographic travel history prior to death. During analysis and interpretation, investigators assume that the hair collected from a postmortem environment has not been altered by exposure conditions and that the isotopic “signatures” of hair prior to exposure are preserved in postmortem samples. In order to confidently make inferences from postmortem hair samples, it is necessary to know whether their isotope ratios undergo postmortem changes. To address this question, post-exposure hair samples (n = 44) were collected from known body donors at the Anthropology Research Facility in Knoxville, Tennessee, USA, at various time points ranging from 22 to 1,140 days of exposure. These samples were analyzed for carbon (δ13C), nitrogen (δ15N), hydrogen (δ2H), and oxygen (δ18O) isotope ratios, and the results were compared with pre-exposure hair samples collected from the same donors. This study highlights considerations for the interpretation of isotope ratios obtained from postmortem hair samples in forensic contexts. The results indicate that δ13C, δ15N, and δ18O values from human hair remain relatively consistent over periods up to three years of outdoor exposure, while δ2H values changed significantly between pre-and post-exposure hair samples.