Design and performance of cost-effective ultra high performance concrete for bridge deck overlays

The main objective of this research is to develop a cost-effective ultra-high performance concrete (UHPC) for bonded bridge deck overlays. The high durability and mechanical properties of such repair material can offer shorter traffic closures and prolong the service life of the pavement. The UHPC was optimized using supplementary cementitious materials (SCMs), proper combinations of sands, and adequate selection of fiber types and contents. Packing density studies included paste, sand, and fiber combinations. The robustness of optimized UHPC mixtures to variations of mixing and curing temperatures was examined. The efficiency of various shrinkage mitigation approaches in reducing autogenous and drying shrinkage of optimized UHPC mixtures was evaluated. This included the use of CaO-based and MgO-based expansive agents, shrinkage-reducing admixture, and pre-saturated lightweight sand. Optimized UHPC mixtures were cast as thin bonded overlays of 25, 38, and 50 mm in thickness over pavement sections measuring 1 × 2.5 m². Early-age and long-term deformation caused by concrete, humidity and temperature gradients, as well as cracking and delamination were monitored over time. Test results indicate that the designed UHPC mixtures exhibited relatively low autogenous shrinkage and drying shrinkage. The G50 mixture had the lowest autogenous and drying shrinkage of 255 µm/m at 28 days and 55 µm/m at 98 days, respectively. All tested UHPC mixtures exhibited a high mechanical properties and excellent frost durability. The use of 60% lightweight sand led to significantly reduction in autogenous shrinkage from 530 to 35 µm/m. Test results indicate that there was no surface cracking or delamination in UHPC overlays after 100 days of casting --Abstract, page iii

An Empirical Study of Value Creation Criteria: Case of Iran

Today’s investors, creditors, and managers are look for an on-time and reliable index, with the goal of evaluating value creation amount. The aim of this study is inducing of voluble measures to users and increasing their understanding yielded these measures by comprise informative contexts accounting and economic measures for this purpose, present study by testing hypotheses and selecting 92 companies listed in Tehran’s Stock Exchange, from 2004 to 2008 is performed. The results of the study reveal that there is meaningful relation between accounting measures, just ROI and EPS with value creation.value creation, performance analysis, economic measures, and accounting measures

A New, Simple and Practical Approach to Increase the Effects of Aerobic Exercise on Serum Levels of Neurotrophic Factors in Adult Males

International Journal of Exercise Science 16(2): 932-941, 2023. Environmental enrichment (EE) is defined as a combination of complex inanimate and social stimulation. Physical activity and EE may augment the beneficial effects of each other. This study aimed to assess the effects of running in an enriched environment on neurotrophic factors in adult males. Twelve volunteer adult males (age 26.75 ± 5.34 yrs, body mass 70.72 ± 8.61 kg, height 172.50 ± 5.68 cm, VO2max 56.8 ± 2.93) completed two sessions, each consisted of one hour of running at an intensity of 12-13 on the Borg Scale. One session was completed in a normal environment, while the other was performed in an enriched environment (running track with several obstacles). Participants completed this randomized cross-over study interspersed by two weeks. Ten minutes before and after each session, blood samples were collected from all participants. Serum levels of BDNF, IGF-1, and VEGF were measured by ELISA. There was a statistically significant interaction of condition and exercise on BDNF, F (1, 11) = 43.71, p \u3c 0.001, = 0.799; IGF-1, F (1, 11) = 83.58, p \u3c 0.001, = 0.884; and VEGF, F (1, 11) = 31.86, p \u3c 0.001, = 0.743. There was also a significant effect of condition on BDNF F (1, 11) = 21.08, p = 0.001, = 0.657; IGF-1, F (1, 11) = 32.35, p \u3c 0.001, = 0.746; and VEGF, F (1, 11) = 116.29, p \u3c 0.001, = 0.914. In addition, there was a significant effect of Exercise on BDNF F (1, 11) = 52.86, p \u3c 0.001, = 0.828; IGF-1, F (1, 11) = 39.14, p \u3c 0.001, = 0.781; and VEGF, F (1, 11) = 171.21, p \u3c 0.001, = 0.940. One hour of moderate-intensity running in adult males significantly increased serum levels of BDNF, IGF-1, and VEGF. But, exercising in an enriched environment may have a significantly greater effect. Therefore, if enhancing neurotrophic factors are desired outcomes of training sessions, then including obstacles may enhance the likelihood of achieving this goal

Physical activity and colorectal cancer

Colorectal cancer is one of the most common cancers in the world. In developed countries 60% of the populations are at risk of this cancer, and colorectal cancer is considered as 10% and 11% of newly diagnosed cancers among men and women, respectively (1). The Europe Society of Gastroenterology declared that colorectal cancer is the most common cancer in 2000. The incidence of colorectal cancer varies in different parts of the world, so that the highest incidence is visible in developed countries such as America, Australia, West Europe and New Zealand and lowest in countries such as South of America, Africa and Asia (2, 3). Colorectal cancer is a multifactorial disease with a set of genetic and environmental factors. In this disease a series of factors such as lifestyle, nutrition and physical activity play a key role in susceptibility to cancer. The role of physical activity in susceptibility to colorectal cancer has received special attention; so that the findings resulted out of most of these studies indicate the effect of physical activity in reducing the risk of suscptibility to colorectal cancer (4, 5). In fact, there is a reverse relationship between physical activity and colorectal cancer, in such a way that the risk of colorectal cancer in people with physical activity in their free time is 27% less than people without physical activity are (6). Severe physical activity is associated with the reduced risk of colon cancer, so that the relative risk of proximal and distal colon cancer in severe physical activity group compared with no physical activity group was 0.73(95% CI, 0.66–0.81), and 0.74 (95% CI, 0.68–0.80), respectively (7). People who have a history of continuous physical activity during the past 20 yr have more benefits from the protective effects of exercise in reducing the risk of occurrence of colon cancer (4). In men and women with high physical activity, incidence of colorectal cancer compared to those with little or no physical activity reduced by 40%–50% (8). In people that during their leisure time had at least 60 min of daily physical activity compared to those who had physically active for 10 min or less, the hazard ratio of colorectal cancer was 0.57 (95% CI, 0.41–0.79). Hazard ratio for colon cancer was 0.56 (95% CI, 0.37–0.83) and for rectal cancer was 0.59 (95% CI, 0.34–1.02) (9). In recent years, mechanisms by which physical activity reduces the risk of colorectal cancer, were not entirely clear, albeit assumptions such as changes in the material in gastrointestinal transmit time, changes in immune function as well as changes in prostaglandin levels, insulin, insulin-like growth factors, bile acid secretion, serum cholesterol as well as pancreatic and gastrointestinal hormone profiles are presented. There is currently limited empirical data in epidemiologic studies on humans and animals in order to approve each of these mechanisms in reducing the risk of colorectal cancer; therefore, it is probable that beneficial effect of physical activity in reducing colorectal cancer has been due to the combined effects of these factors and other unknown factors (10). Doctors recommend physical activity for the general population with the aim of reducing the burden related to colorectal cancer. However, doctors do not need a full understanding of this mechanism. Therefore, in health education programs and medical advice for reducing the risk of colorectal cancer, physicians must pay particular attention to the protective effect of exercise and physical activity, and at the same time conduct scientific and biological surveys to achieve a clearer understanding of the beneficial mechanisms of physical activity in reducing risk of colorectal cancer

Predict the future incidence and mortality of breast cancer in Iran from 2012-2035

Global Breast Cancer (BC) is the most common non-skin malignancy, nearly a third of newly diagnosed cancers in the United States and the second leading cause of mortality in women throughout the world was BC (1, 2). Between 1975 and 2000 the burden of BC has doubled, that is attributable to the increase in life expectancy and spread of unhealthy lifestyle (3). Nevertheless, these trends are not visible in early onset of BC, as the rates have been more or less stable in most countries in the past 20 yr (4). As for mortality rates, they have been progressively decreasing, particularly in younger women, due to the improved treatment and primary detection (5). In Iran with increasing life expectancy and the aging of the residents, the incidence and mortality of BC will increase in the future years (6). In GLOBOCAN project, the expected number of new cancer cases or deaths in a country or region in 2015–2035 is computed by multiplying the age-specific incidence/mortality rates estimated for 2012, by the corresponding expected population for 2015–2035. In Iran, based on the GLOBOCAN project in 2012, the number of BC in woman was 9795 case and the number of new case have an increase in the next few years, so in 2015, 2020, 2025, 2030 and 2035 the number of new cases were 10982, 12684, 14920, 17346 and 19328, respectively. Therefore, in 2035 compare 2012 the numbers of new case were nearly 2 times. In addition, in 2012, the numbers of death from BC was 3304 and in the next few years, we have increase in the number of death from BC, so in 2015, 2020, 2025, 2030 and 2035 the numbers of deaths were 3742, 4394, 5248, 6220 and 7138. We expect that Iranian population structure, the greatest increase in the number of new cases and deaths from BC observe in age group (ages >= 65), so in 2035 compared to 2012, the number of new case and mortality will be 3 times, while in the age group below 65 yr, the increase is about 1.8 time

The prevalence of Jaw and temporomandibular disorders and its relationship with malocclusions in children

In recent years the number of patients with temporomandibular disorders (TMDs) is on the rise, given this, this paper aimed to investigate the prevalence of jaw and TMDs and its relationship with malocclusions in children. This study was conducted as a review article. The study was a descriptive – library type in which by referring to all the resources and literature of the existing studies, their results have been summed up. The TMDs is referred to clinical problems that involve masticatory muscles, temporomandibular joints or both of them. Its prevalence is 12 to 20%, and including subclinical symptoms, it reaches to 65 %. The common age is reported to be between 20 and 40 years, and its prevalence is higher in women. The most common symptoms are masticatory muscle pain, and the most common cause of it is premature contacts. Its treatment includes two phases;  the first phase includes reducing anxiety, medication, and physiotherapy. The second phase involves orthodontic treatment

Assessment the relationship between Testis Cancer incidence and mortality rate with human development index in the European countries in 2012

Testis Cancer (TC) is the most common cancer in 15-39 year-old men and with the white Caucasian race. This cancer consists of 0.7 percent of men's cancer all over the world. The aim of this study is to investigate the relationship between the Age-Standardised Incidence Rates (ASIR) and Age-Standardised Mortality Rates (ASMR) of TC with Human Development Index (HDI) and its components at the European countries in 2012. This study was an ecologic study in European countries for assessment the correlation between ASIR and ASMR with HDI and its details including: Life expectancy at birth, Mean years of schooling and Gross National Income (GNI) per capita. We use correlation bivariate method for assessment the correlation between SIR and SMR with HDI and its components. Data of study was analyzed by SPSS15statistical analysis software; the significance level of the tests was considered P<0.05. The results of the data investigation showed that the maximum ASIR of TC was observed respectively in the countries of Norway, Switzerland, and Denmark. Moreover findings showed the highest ASMR was in the countries of Hungary, Bulgaria and FYR Macedonia. The ASIR was positively correlated with HDI equal to 0.623( p <= 0.001), with Life expectancy at birth equal to 0.602( p <= 0.001), with the average years of schooling equal to 0.339( p= 0.032) and with country's Gross National Income ( GNI) per capita equal to 0.466( p= 0.002). The ASMR was negatively correlated with HDI equal to 0.537( p <= 0.001), life expectancy at birth equal t

Robustness of Ultra-High-Performance Concrete to Changes in Material Temperature

Ultra-high-performance concrete (UHPC) can be vulnerable to variations in materials properties and environmental conditions. In this paper, the sensitivity of UHPC to changes in mixing, casting, curing, and testing temperatures ranging between 10 and 30 ± 2°C (50 and 86 ± 3.5°F) was investigated. The investigated rheological properties, mechanical properties, and shrinkage of UHPC are shown to be significantly affected by temperature changes. UHPC made with either binary or ternary binder containing fly ash (FA) or slag cement exhibited greater robustness than mixtures prepared with 25% silica fume. UHPC made with 60% FA necessitated the lowest high-range water-reducing admixture demand. With temperature increase, the yield stress of UHPC mixtures increased by up to 55%, and plastic viscosity decreased by up to 45%. This resulted in accelerating initial and final setting times by up to 4.5 and 5 hours, respectively. The increase of temperature from 10 to 30 ± 2°C (50 ± to 86 ± 3.5°F) led to a 10 to 75% increase in compressive, splitting tensile, and flexural strengths and modulus of elasticity and 15 to 60% increase in autogenous shrinkage

Debonding Test Method to Evaluate Bond Strength between UHPC and Concrete Substrate

The use of the pull-off test to evaluate the interfacial bond strength between substrate concrete and bonded materials can result in failure of the concrete substrate without clear indication of the interfacial bond strength. Proper knowledge of the interfacial bond strength between a repair material and concrete substrate is critical for the selection of repair materials and for the modeling of the performance of the composite section. This includes ultra-high performance concrete (UHPC) used for thin bonded overlays of concrete bridge decks. The bond strength of UHPC to concrete substrate sections was evaluated in this study using the pull-off test, a modified version of the pull-off test, and the modified splitting tensile strength test. The results identified some challenges with respect to the characterization of interfacial bond and associated variability of test results. A new test method proposed to determine the interfacial bond strength showed that bond strength can range between 2.3 and 3.5 MPa and low coefficient of variation of 1.4% and 3.4%, respectively

Coupled Effect of Shrinkage-Mitigating Admixtures and Saturated Lightweight Sand on Shrinkage of UHPC for Overlay Applications

This paper evaluates the efficiency of various shrinkage mitigation approaches in reducing autogenous and drying shrinkage of ultra high performance concrete (UHPC). This included the use of various contents of CaO-based and MgO-based expansive agents, shrinkage-reducing admixture, and pre-saturated lightweight sand. Workability, compressive strength development, autogenous and drying shrinkage were evaluated for UHPC mixtures subjected to moist curing periods of 1, 3, and 7 d. Test results indicate that the use of lightweight sand was shown to be more effective in mitigating shrinkage than enhancing compressive strength. The replacement of natural sand by 60% of lightweight sand, by volume, was found to reduce autogenous shrinkage from 530 to 35 µm/m at 91 d. The coupled effect of using 60% lightweight sand and either CaO-based expansive agent, MgO-based expansive agent, or shrinkage-reducing admixture can reduce autogenous shrinkage at 91 d by up to 600 µm/m and drying shrinkage by up to 700 µm/m. In some combination, the use of shrinkage mitigating admixtures was found to reduce the 91-d compressive strength ranging from 8 to 20 MPa, even when 60% lightweight sand was employed. The initial moist curing period had positive effect on mitigating total shrinkage. The incorporation of 10% CaO-based expansive agent in UHPC with 60% lightweight sand subjected to 7 d of moist curing exhibited the best overall performance with 91-d autogenous shrinkage of 110 µm/m in expansion and 91-d total shrinkage (autogenous shrinkage after 1 d plus drying shrinkage) of 580 µm/m (also in expansion)