Eco-Concrete in High Temperatures.

Concrete technology is becoming more and more sustainable and ecological following more extensive and focused research. The usage of industrial waste and by-products, such as steel ground granulated blast-furnace slag (GGBFS), mine tailing, fly ash, and recycled fibers, is a very important step toward a good transition of concrete into a "green" future and significant improvement in waste management in the world. However, there are also several known durability-related problems with some types of eco-concretes, including exposure to fire. The general mechanism occurring in fire and high-temperature scenarios is broadly known. There are many variables that weightily influence the performance of this material. This literature review has gathered information and results regarding more sustainable and fire-resistant binders, fire-resistant aggregates, and testing methods. Mixes that utilize industrial waste as a total or partial cement replacement have been consistently achieving favorable and frequently superior outcomes when compared to conventional ordinary Portland cement (OPC)-based mixes, especially at a temperature exposure up to 400 °C. However, the primary emphasis is placed on examining the impact of the matrix components, with less attention given to other factors such as sample treatment during and following exposure to high temperatures. Furthermore, there is a shortage of established standards that could be utilized in small-scale testing.

Interpretable Machine Learning for Prediction of Post-Fire Self-Healing of Concrete.

Developing accurate and interpretable models to forecast concrete's self-healing behavior is of interest to material engineers, scientists, and civil engineering contractors. Machine learning (ML) and artificial intelligence are powerful tools that allow constructing high-precision predictions, yet often considered "black box" methods due to their complexity. Those approaches are commonly used for the modeling of mechanical properties of concrete with exceptional accuracy; however, there are few studies dealing with the application of ML for the self-healing of cementitious materials. This paper proposes a pioneering study on the utilization of ML for predicting post-fire self-healing of concrete. A large database is constructed based on the literature studies. Twelve input variables are analyzed: w/c, age of concrete, amount of cement, fine aggregate, coarse aggregate, peak loading temperature, duration of peak loading temperature, cooling regime, duration of cooling, curing regime, duration of curing, and specimen volume. The output of the model is the compressive strength recovery, being one of the self-healing efficiency indicators. Four ML methods are optimized and compared based on their performance error: Support Vector Machines (SVM), Regression Trees (RT), Artificial Neural Networks (ANN), and Ensemble of Regression Trees (ET). Monte Carlo analysis is conducted to verify the stability of the selected model. All ML approaches demonstrate satisfying precision, twice as good as linear regression. The ET model is found to be the most optimal with the highest prediction accuracy and sufficient robustness. Model interpretation is performed using Partial Dependence Plots and Individual Conditional Expectation Plots. Temperature, curing regime, and amounts of aggregates are identified as the most significant predictors.

Hybrid Interfacial Transition Zone between Wet-On-Wet Casted Concrete-Microstructure and Mechanical Properties.

The manufacture of elements containing two types of concrete allows for the minimization of the amount of Portland cement by matching the properties of concrete with local structural and durability requirements. The most common production method of the hybrid element is wet-on-hard and wet-on-wet. Casting wet-on-dry is the most common approach while casting wet-on-wet has been used mostly for concrete overlays and screeds. The study focuses on the wet-on-wet method but is applied in the production of vertical and horizontal elements. Bond-behavior and micro properties of the wet-on-wet casting interface of ultra-high-performance concrete (UHPC)-normal strength concretes are investigated. The obtained results indicate the formation of a hybrid interfacial transition zone between the two types of casted concrete. The binder matrix located in this zone appeared to combine properties of both used concrete. Porosity, phase composition, and presumably also strength, changed gradually. Furthermore, despite significant differences in shrinkage, no microcracking or delamination was observed in that zone. The ultimate flexural and compressive strength of the produced elements were either equal to the stronger concrete or were higher than the weaker of the used concrete.

A Review of the Mechanical Properties and Durability of Ecological Concretes in a Cold Climate in Comparison to Standard Ordinary Portland Cement-Based Concrete.

Most of the currently used concretes are based on ordinary Portland cement (OPC) which results in a high carbon dioxide footprint and thus has a negative environmental impact. Replacing OPCs, partially or fully by ecological binders, i.e., supplementary cementitious materials (SCMs) or alternative binders, aims to decrease the carbon dioxide footprint. Both solutions introduced a number of technological problems, including their performance, when exposed to low, subfreezing temperatures during casting operations and the hardening stage. This review indicates that the present knowledge enables the production of OPC-based concretes at temperatures as low as -10 °C, without the need of any additional measures such as, e.g., heating. Conversely, composite cements containing SCMs or alkali-activated binders (AACs) showed mixed performances, ranging from inferior to superior in comparison with OPC. Most concretes based on composite cements require pre/post heat curing or only a short exposure to sub-zero temperatures. At the same time, certain alkali-activated systems performed very well even at -20 °C without the need for additional curing. Chemical admixtures developed for OPC do not always perform well in other binder systems. This review showed that there is only a limited knowledge on how chemical admixtures work in ecological concretes at low temperatures and how to accelerate the hydration rate of composite cements containing high amounts of SCMs or AACs, when these are cured at subfreezing temperatures.

The Effect of Exposure on the Autogenous Self-Healing of Ordinary Portland Cement Mortars.

Exposure conditions are critical for the autogenous self-healing process of Portland cement based binder matrixes. However, there is still a significant lack of fundamental knowledge related to this factor. The aim of this paper was to investigate and understand the effects of various potentially applicable curing solutions on the efficiency of the crack closure occurring both superficially and internally. Four groups of exposures were tested, including exposure with different water immersion regimes, variable temperatures, application of chemical admixtures, and use of solutions containing micro particles. The self-healing process was evaluated externally, at the surface of the crack, and internally, at different crack depths with the use of optical and scanning electron microscopes (SEM). The phase identification was done with an energy dispersive spectrometer combined with the SEM. The results showed very limited self-healing in all pure water-based exposures, despite the application of different cycles, temperatures, and water volumes. The addition of a phosphate-based retarding admixture demonstrated the highest crack closure, both internally and externally. The highest strength recovery and a very good crack closure ratio was achieved in water exposure containing micro silica particles. The main phase observed on the surface was calcium carbonate, and internally, calcium silicate hydrate, calcium carbonate, and calcium phosphate compounds. Phosphate ions were found to contribute to the filling of the crack, most likely by preventing the formation of a dense shell composed of hydration phases on the exposed areas by crack unhydrated cement grains as well as by the additional precipitation of calcium and phosphate-based compounds. The micro sized silica particles presumably served as nucleation sites for the self-healing products growth. Changes in the chemical composition of the self-healing material were observed with a distance from the surface of the specimen.

Does a High Amount of Unhydrated Portland Cement Ensure an Effective Autogenous Self-Healing of Mortar?

It is commonly accepted that the autogenous self-healing of concrete is mainly controlled by the hydration of Portland cement and its extent depends on the availability of anhydrous particles. High-performance (HPCs) and ultra-high performance concretes (UHPCs) incorporating very high amounts of cement and having a low water-to-cement ratio reach the hydration degree of only 70-50%. Consequently, the presence of a large amount of unhydrated cement should result in excellent autogenous self-healing. The main aim of this study was to examine whether this commonly accepted hypothesis was correct. The study included tests performed on UHPC and mortars with a low water-to-cement ratio and high cement content. Additionally, aging effects were verified on 12-month-old UHPC samples. Analysis was conducted on the crack surfaces and inside of the cracks. The results strongly indicated that the formation of a dense microstructure and rapidly hydrating, freshly exposed anhydrous cement particles could significantly limit or even hinder the self-healing process. The availability of anhydrous cement appeared not to guarantee development of a highly effective healing process.

Severe postprostatectomy incontinence: Is there an association between preoperative urodynamic findings and outcome of incontinence surgery?

OBJECTIVE: This study investigated urodynamic findings in prostate cancer patients with self-reported persistent severe postprostatectomy urinary incontinence (PPI) as well as the outcome of incontinence surgery. The main aim was to evaluate the ability of preoperative urodynamic dysfunctions to predict the outcome of incontinence surgery. The hypothesis was that preoperative bladder dysfunction was predictive of an unsuccessful surgical outcome. MATERIALS AND METHODS: Based on patient-reported adverse effects after radical prostatectomy (RP) in 2005-2009, 94 men with persistent severe PPI were invited in 2011 to a clinical examination including urodynamics. When indicated, surgery for PPI was offered, and by January 2014, 46 patients had been operated on with either an artificial urinary sphincter or a sling. The outcome of PPI surgery was evaluated with a follow-up questionnaire. Successful outcome was defined in two ways: patient-reported satisfaction and using one or fewer pads/day. RESULTS: Of the 94 men with severe PPI more than 12 months after RP, 76 patients (81% response rate) met for clinical examination. Among them, 99% had intrinsic sphincter deficiency, in 67% coexisting with urodynamic bladder dysfunction. The presence of preoperative bladder dysfunction was not predictive of the outcome of PPI surgery. Preoperative use of fewer pads, less severe PPI, and a longer interval between RP and PPI surgery were associated with the successful outcome of one or fewer pads/day. Longer duration from RP to PPI surgery was the only preoperative factor associated with the successful outcome of satisfaction. CONCLUSIONS: The hypothesis was not supported as the presence of preoperative urodynamic bladder dysfunction was not predictive of the outcome of PPI surgery in this study.

How should continence and incontinence after radical prostatectomy be evaluated? A prospective study of patient ratings and changes with time.

PURPOSE: We examined prevalence rates, and changes in continence and incontinence before and after radical prostatectomy for prostate cancer by comparing different definitions. We also studied the descriptive validity of the grading system of Ellison et al for post-prostatectomy incontinence and baseline predictors of post-prostatectomy incontinence at 12 months. MATERIALS AND METHODS: This national prospective study included 844 patients treated with radical prostatectomy between 2005 and 2009. Adverse effects, including urinary dysfunction and bother, were reported by 735 patients (88%) using the EPIC-50 and UCLA-PCI validated questionnaires at baseline and 12-month followup. Linear regression analysis was done to examine baseline predictors and the degree of post-prostatectomy incontinence at followup. RESULTS: At 12 months after radical prostatectomy 74% of patients reported post-prostatectomy incontinence, of whom 40% used pads daily, 34% reported occasional dribbling without pads and 26% had total urinary control. When defined as total incontinence/no urinary control, severe post-prostatectomy incontinence was reported by 3% of the men but 25% had severe post-prostatectomy incontinence according to the stratification of Ellison et al. Of patients with preoperative incontinence 14% improved postoperatively. Predictors of post-prostatectomy incontinence were age 65 years or greater, not working, sexual dysfunction and incontinence preoperatively. The latter 2 remained the strongest predictors on multivariate analysis. Prostate cancer related variables were not associated with post-prostatectomy incontinence. CONCLUSIONS: The prevalence of post-prostatectomy incontinence varied considerably according to the definition applied. In our opinion incontinence may be reported as any leakage and not only as pad use with grading done on a symptom scale. Preoperative sexual dysfunction and urinary incontinence were the strongest predictors of post-prostatectomy incontinence at 12-month followup.

Study of generic quality of life in patients operated on for post-prostatectomy incontinence.

BACKGROUND: The relationship between urological and psychosocial variables, and generic quality of life in patients operated on for post-prostatectomy incontinence has hardly been studied, and our aim was to investigate this relationship. METHODS: Patients who had an artificial urinary sphincter AMS800 (n = 100) implanted between January 2002 and June 2010 were invited to complete a mailed questionnaire covering demographic data including work ability, urinary and sexual function, anxiety/depression, and generic quality of life. Poor quality of life was defined as a score <40 on either the physical or the mental Short Form 12 summary scales. RESULTS: Of 85 compliant patients, 30 (35%) reported poor generic quality of life and 55 (65%) reported better quality of life at a median follow-up time of 26 months (range 6-104 months). The poor quality of life group showed significantly more overall urinary and sexual problems, and more men had undergone surgical revisions compared with the better quality of life group. Levels of anxiety and depression were significantly higher, and work ability was lower in the poor quality of life group. In multivariate logistic regression models, increased level of depression and impaired work ability, inability to reach orgasm, and not recommending the operation remained significantly associated with poor quality of life. CONCLUSION: Poor generic quality of life after surgery for post-prostatectomy incontinence is more strongly associated with reduced work ability and depression rather than urinary and sexual problems.

Long-term experience with surgical treatment of selected patients with bladder pain syndrome/interstitial cystitis.

OBJECTIVE: The role of major surgery in patients with bladder pain syndrome/interstitial cystitis (BPS/IC) is not fully established. This report presents a single-institution experience with major surgery in patients with disabling BPS/IC where conservative treatment had failed. MATERIAL AND METHODS: Forty-one patients (34 women, seven men) with BPS/IC refractory to conservative treatment underwent major surgery from 1983 to 2004. Surgical approach was determined on a case-by-case basis. Postoperative pain and satisfaction were assessed by a questionnaire. RESULTS: Cystectomy was the primary procedure in five patients. The remaining 36 patients were primarily operated on with subtotal cystectomy and bladder augmentation (n = 16) or supravesical urinary diversion with intact bladder (n = 20). Thirteen of these patients were later operated on with cystectomy due to persisting pain 12 (6-146) months after the primary procedure. The questionnaire was answered by 38 of 41 patients after a median follow-up of 66 (6-238) months. In total, 28 patients (74%) were free of pain, and 26 patients (68%) were satisfied with the end result. There was no difference in reported pain between cystectomized and non-cystectomized patients. When comparing patients who reported pain at follow-up with those who did not report pain, preoperative length of symptoms was significantly increased, with 12.1 compared to 5.4 years (p = 0.02). CONCLUSIONS: Major surgery is associated with good symptom relief in strictly selected patients with disabling BPS/IC, where conservative treatment has failed. Extended preoperative duration of symptoms may be a predictor for persisting pain after major surgery for BPS/IC.

Evaluation of patients after treatment of arterial priapism with selective micro-embolization.

OBJECTIVE: Arterial (high-flow) priapism is characterized by a prolonged non-painful erection without sexual arousal as a result of unregulated inflow of blood to the corpus cavernosum. Treatment is based on decreasing this elevated inflow, primarily by means of selective arteriography and embolization. The aim of this study was to evaluate the treatment of patients with arterial priapism. MATERIAL AND METHODS: In the period between 1990 and 2004, 10 patients with arterial priapism were admitted to our department. The mean age when priapism developed was 32 years (range 11-62 years). Eight patients were treated with selective embolization, one was operated on and one refused treatment. Nine patients completed a standardized questionnaire which included the International Index of Erectile Function (IIEF-5). The mean follow-up time after treatment was 70 months. RESULTS: All patients treated with selective embolization achieved reduced tumescence. Six out of eight patients had an improved IIEF-5 score after treatment. In nine men, the etiology of the arterial priapism was perineal trauma. In one case, an anomaly with an accessory artery to the corpus cavernosum was diagnosed, which required surgery, and in one case recurrence of the priapism necessitated a second embolization. CONCLUSIONS: Selective embolization results in reduced tumescence and an improvement in erectile function in patients with arterial priapism. Trauma to the perineum was the main etiology in this study.

[Treatment of erectile dysfunction with penile implants]. / Behandling av ereksjonssvikt med penisimplantat.

BACKGROUND: Penile implants are the final step in the treatment of erectile dysfunction. The aim of this study was to evaluate patients treated with penile implants in our department. MATERIAL AND METHODS: From 1990 to 2002, 37 men with erectile dysfunction were treated with a three-component penile implant (AMS 700). In 2 patients the implant was removed; 2 patients were dead at the time of the study. The remaining group (n = 33) received a questionnaire concerning their penile implants, of whom 27 (82 %) responded. Mean observation time after surgery was 6 years. Mean age at surgery was 50 (27 - 68 years). RESULTS: Diabetes mellitus, trauma and venous insufficiency were the main reasons (68 %) for dysfunction in this patient group. Five patients had perioperative or early postoperative complications. Nineteen (51 %) were re-operated mainly because of dislocation (n = 5), perforation (n = 4) or mechanical failure (n = 4) of the implant. Twenty (74 %) patients were satisfied after surgery. There was no significant improvement in libido or in the relationship with partners. INTERPRETATION: Three out of four patients were pleased to have the penile implantation done despite the high reoperation rate.

Pharmacotherapy for erectile dysfunction.

INTRODUCTION: Advances in understanding of the biochemistry and physiology of penile erection have led to breakthroughs in pharmacotherapy of erectile dysfunction. AIM: To provide recommendations/guidelines concerning state-of-the-art knowledge for the putative molecular and cellular mechanisms of action of centrally and peripherally acting drugs currently utilized in pharmacotherapy of erectile dysfunction. METHODS: An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various male and female sexual medicine topics. The recommendations concerning state-of-the-art knowledge in the respective sexual medicine topic represent the opinion of experts from five continents developed in a process over a two-year period. Concerning the Pharmacotherapy for Erectile Dysfunction Committee there were 25 experts from 10 countries. MAIN OUTCOME MEASURE: Expert opinion was based on grading of evidence-based medical literature, widespread internal committee discussion, public presentation and debate. RESULTS: Selective and potent oral PDE5 inhibitors have significantly more affinity than cGMP and form broader molecular interactions with multiple amino acids, thereby blocking access to cGMP in the catalytic sites of the PDE5 enzyme. PDE5 inhibitors, which vary as to biochemical potency, selectivity and pharmacokinetics, lead to cGMP elevation and relaxation facilitation of penile corpus cavernosum smooth muscle cells following sexual stimulation. Various centrally acting drugs influence sexual behaviour. In particular, the dopaminergic substance apomorphine is a central enhancer that acts in the paraventricular nucleus of the hypothalamus as a dopamine (D2) receptor agonist, induces and increases penile erection responses via disinhibition, following sexual stimulation. CONCLUSIONS: There is a need for more research in the pharmacotherapeutic development of central and peripheral agents for safe and effective erectile dysfunction treatment.

[Expandable penile implants in patients with erectile dysfunction]. / Penisimplantat ved ereksjonssvikt.

Modern medical treatment can restore normal sexual function in the majority of men with erectile dysfunction, but some men will not obtain an erection sufficient for sexual intercourse. In some of these men, with a strong desire to have an active sexual life including intercourse, it is possible to restore the function by the use of a penile implant. We describe the indications, the surgical procedure and the results with an expandable penile implant.

Sacral neuromodulation in Norway: clinical experience of the first three years.

We present our first three years' experience of sacral neromodulation as first line therapy in patients with a non-neurogenic refractory urge incontinence. In 53 patients, 45 women and 8 men with a mean age of 54 years (range 17-76 years), tested by subacute percutan nerve evaluation, 19 patients were declared as responders according to our programme. Fourteen patients, twelve women and two men with a mean age of 47 years (range 33-73 years), agreed to implantation of a neuroprosthesis (Medtronic Interstim Model 3031), which was placed in a subcutaneous buttock pocket in 12 patients. In the first two patients, the device was implanted subcutaneously corresponding to the lower quadrants of the abdominal wall. In two patients, the lead was repositioned from S:4 to S:3 six to twelve months after the primary implantation. In one woman with sensory urgency, the neuroprosthesis was removed six months after it was implanted because of failure. The patients were followed every six months using voiding diary, uroflowmetry, residual urine and cystometry. Eight patients reported total continence, and five declared >50% improvement. One woman has chronic bacteriuria and intermittently symptomatic urinary tract infection, which reduce the response to the chronic sacral nerve stimulation. Because of residual urine, four women are following an individual self-catheterisation programme. In conclusion, we have documented that sacral neuromodulation is an effective and safe procedure in patients with refractory urge incontinence depending on detrusor overactivity. We confirm the clinical results reported by other centres with long experience of sacral neuromodulation.