Fire Resistance Tests on Thin CFRP Prestressed Concrete Slabs

Optimised, high-performance concrete elements, prestressed with carbon fibre reinforced polymer (CFRP) tendons offer great potential within the sustainable modern built environment. However, the performance of these elements in fire is not well known and must be better understood for applications where fire resistance is required. Findings from large-scale fire resistance tests on thin CFRP prestressed concrete slabs are presented and discussed. Results show that explosive spalling in fire results in sudden collapse, and when spalling is avoided failure occurs by loss of anchorage, which is in turn governed by the temperature of the tendons

Experimental fire behaviour of precast CFRP pretensioned HPSCC slabs

Optimized concrete elements have been developed using high-performance, self-consolidating, fibre-reinforced concrete (HPSCC) reinforced with high-strength, lightweight, non-corroding pre-stressed carbon fibre reinforced plastic tendons. This new type of thin-walled precast carbon FRP (CFRP) pretensioned HPSCC slab has been used in building façades and is under consideration for a range of other applications in buildings. However, it is well known that the bond strength between both steel and FRP reinforcements and concrete deteriorates at elevated temperature, and that HPSCC has a comparatively high risk of heat-induced concrete spalling. Reductions in bond strength, the occurrence of heat-induced concrete spalling, and their impacts on the load-bearing capacity of precast CFRP pretensioned HPSCC slabs during fire are not well understood. This paper gives insights into the fire behaviour of precast CFRP pretensioned HPSCC slabs by evaluating the influence of concrete mixture, slab thickness and the presence of local reinforcement (CFRP grids) in the prestress transfer zones. Selected results and analysis of a large scale fire resistance test on five HPSCC slabs are presented in this paper. It is shown that the occurrence of heat-induced concrete spalling resulted in sudden failure of the specimens, and that in cases where no spalling occurred failure was due to loss of bond strength

Longitudinal Assessment of Physical Activity, Fitness, Body Composition, Immunological Biomarkers, and Psychological Parameters During the First Year After Diagnosis in Women With Non-Metastatic Breast Cancer: The BEGYN Study Protocol

Background: Moderate physical activity is associated with an improved prognosis and psychosocial outcome in breast cancer patients. Although exercise and physical activity are associated with multiple physiological and psychological effects, many of the underlying mechanisms remain obscure. The BEGYN study (Influence of physical activity in breast cancer patients on physiological and psychological parameters and on biomarkers) aims at identifying potential associations between the extent of physical activity, fitness, body composition, immunological biomarkers, psycho-emotional parameters, and the course of treatment during the first year after diagnosis of breast cancer. Methods: The prospective observational BEGYN study will include 110 non-metastatic breast cancer patients. The patients will be assessed during a base line visit prior to the initiation of the antineoplastic therapy and after 3, 6, 9 and 12 months. The physical activity will be measured using a fitness tracker and a self-assessment diary during the entire study. Each visit will include the assessment of (i) cardiorespiratory fitness measured by spiroergometry, (ii) body composition, (iii) psycho-emotional parameters (quality of life, mental health, fatigue, depression, distress, anxiety, well-being), and (iv) extensive blood tests including routine laboratory, vitamin D, selenium and immunologically relevant biomarkers (e.g., leukocyte subpopulations and cytokine profiles). Discussion: Whereas most studies investigating the influence of physical activity in breast cancer patients focus on specific activities for three months or less, the BEGYN study will quantify the daily physical activity and cardiorespiratory fitness of breast cancer patients based on objective measurements in the context of the oncological therapy for 12 months after diagnosis. The study will reveal potential associations between exercise, immune status and physical as well as psycho-emotional outcome and the clinical course of the disease. Moreover, complementary therapies such as Vit D and Selenium supplementation and parameters investigating the motivation of the patients are part of the study. Due to this holistic approach, the BEGYN study will guide towards confirmatory studies on the role of physical activity in breast cancer patients to develop individualized counselling regarding the recommended type and extent of exercise