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Background: In the last decades, day surgery has steadily and significantly grown in many countries, yet the increase has been uneven. There are large variations in day-surgery activity between countries, but also within countries between hospitals and surgeons. This paper explores the variability in day-care activity for elective surgical procedures between Belgian hospitals.Materials and Methods: The administrative hospital data of all patients formally admitted in a Belgian hospital for inpatient or day-care surgery between 2011 and 2013 were analysed and summarized in graphs. During 11 expert meetings with ad-hoc surgical expert groups the variability in day-surgery share between hospitals was discussed in depth.Results: The variability in day-care share between Belgian hospitals is considerable. For 37 out of 486 elective surgical procedures, the variability ranged between 0 and 100%. High national day-care rates do not preclude room for improvement for certain hospitals as for the majority of these procedures there are "low performers". According to the consulted clinical experts, the high variability in day-care share may for the greater part be explained by medical team related factors, customs and traditions, the lack of clinical guidelines, financial factors, organisational factors and patient related factors.Conclusion: If a further expansion of day surgery is envisaged in Belgium the factors that contribute to the current variability in day-surgery rates between hospitals should be addressed. In addition, a feedback system in which hospitals and health care providers have the figures on their percentage of procedures carried out in day surgery compared to other hospitals and care providers (benchmarking) and the monitoring of a number of quality indicators (e.g. unplanned readmission, unplanned inpatient stay, emergency department visit) should be installed. [ABSTRACT FROM AUTHOR]

Background: Postoperative hypocalcaemia, recurrent laryngeal nerve palsy and postoperative bleeding are the most frequent postoperative complications after thyroid surgery, and therefore often used as quality indicators of thyroid surgery. We aimed to assess postoperative morbidity in a high-volume endocrine surgery unit, and to detect which factors are associated with higher risks.Methods: Prospective surgical cohort in a high-volume tertiary referral centre for endocrine surgery in xxx. The first 1500 patients operated with hemi or total thyroidectomy during 2010-2019 were included. Postoperative hypocalcaemia, recurrent laryngeal nerve palsy and postoperative bleeding were assessed in relation to pre- and peri-operative characteristics using multivariable logistic regression analyses, expressed as odds ratios and 95% confidence intervals.Results: Overall, 1043 patients (69.5%) received a total thyroidectomy and 457 (30.5%) a hemithyroidectomy. Permanent hypocalcaemia occurred in 3.1%, permanent recurrent laryngeal nerve palsy in 1.8% and surgical reintervention for bleeding in 2.6%. Younger age, female sex and cancer were risk factors for permanent hypocalcaemia. No clear risk factors could be identified for permanent nerve palsy. Female sex, high body mass index and heavier thyroids were protective against postoperative bleeding after total thyroidectomy.Conclusions: Surgical experience in endocrine surgery seems beneficial for clinical outcomes and contributes to organizational efficiency. A low complication risk can be obtained by trained high-volume endocrine surgeons, yet the risk is not negligible. [ABSTRACT FROM AUTHOR]

Cracks in reinforced concrete structures exposed to a marine environment or de-icing salts can cause major durability issues due do accelerated ingress of chloride ions. In this study, the influence of autonomous crack healing by means of encapsulated polyurethane on the chloride ingress perpendicular to cracks was evaluated. This was done quantitatively by determining perpendicular-to-crack chloride profiles by means of profile grinding followed by potentiometric titration and qualitatively through visualization of the chloride penetration front by means of the AgNO3 spray method. The resulting chloride profiles showed that the healing mechanism was able to reduce the chloride concentrations in the direct vicinity of the crack to a large extent and to reduce the perpendicular-to-crack chloride penetration, especially further away from the exposed surface. Visualization of the chloride penetration front showed some variation in crack healing. For some healed samples almost no additional chloride ingress was found compared to uncracked samples, others showed a slightly enhanced ingress at the crack location but less perpendicular-to-crack chloride penetration compared to untreated cracked samples. Generally, the reduced amount of chlorides present in the concrete matrix due to crack healing will enhance the durability and service life of concrete structures.

As one of the major causes of concrete deterioration, the carbonation of concrete has been widely investigated over recent decades. In recent years, the effect of mechanical load on carbonation has started to attract more attention. The load-induced variations in crack pattern and pore structure have a significant influence on CO 2 transport which determines the carbonation rate. With different types of load, the number, orientation, and position of the induced cracks can be different, which will lead to different carbonation patterns. In this review paper, the carbonation in cracked and stress-damaged concrete is discussed first. Then, literature about the effect of sustained load during carbonation is compared in terms of load type and load level. Finally, the advantages and disadvantages of possible test methods for investigating the effect of sustained load on carbonation are discussed with respect to loading devices, load compensation, and specimen size.

Beneficiating fly ash as valuable construction material such as artificial lightweight aggregate (LWA) could be an alternative solution to increase the utilization of the industrial by-product. However, generally, LWA is characterized by high porosity and a related high water absorption, which on the one hand allows production of lightweight mortar, but on the other hand can affect its performance. Thus, in this research, the durability performance of mortar composed with alkali-activated fly ash-based LWA, and commercial expanded clay (EC) LWA was investigated. The fly ash LWA was prepared in a pan granulator, with a 6-molar solution of NaOH mixed with Na 2 SiO 3 in a Na 2 SiO 3 /NaOH weight ratio of 1.5 being used as activator (FA 6M LWA). The results revealed that mortar containing FA 6M LWA had equivalent mechanical strength with mortar containing EC LWA. The mortar containing FA 6M LWA had comparable capillary water uptake and chloride migration resistance with the reference and EC LWA mortar. Furthermore, the addition of FA 6M LWA was proven to enhance the carbonation resistance in the resulting mortar, due to the denser interfacial transition zone (ITZ) of mortar with LWA.

Today, a rather poor carbonation resistance is being reported for high-volume fly ash (HVFA) binder systems. This conclusion is usually drawn from accelerated carbonation experiments conducted at CO 2 levels that highly exceed the natural atmospheric CO 2 concentration of 0.03-0.04%. However, such accelerated test conditions may change the chemistry of the carbonation reaction (and the resulting amount of CH and C-S-H carbonation), the nature of the mineralogical phases formed (stable calcite versus metastable vaterite, aragonite) and the resulting porosity and pore size distribution of the microstructure after carbonation. In this paper, these phenomena were studied on HVFA and fly ash + silica fume (FA + SF) pastes after exposure to 0.03-0.04%, 1% and 10% CO 2 using thermogravimetric analysis, quantitative X-ray diffraction and mercury intrusion porosimetry. It was found that none of these techniques unambiguously revealed the reason for significantly underestimating carbonation rates at 1% CO 2 from colorimetric carbonation test results obtained after exposure to 10% CO 2 that were implemented in a conversion formula that solely accounts for the differences in CO 2 concentration. Possibly, excess water production due to carbonation at too high CO 2 levels with a pore blocking effect and a diminished solubility for CO 2 plays an important role in this., Competing Interests: We have no competing interests.

Huge amounts of waste are being generated, and even though the incineration process reduces the mass and volume of waste to a large extent, massive amounts of residues still remain. On average, out of 1.3 billion tons of municipal solid wastes generated per year, around 130 and 2.1 million tons are incinerated in the world and in Belgium, respectively. Around 400 kT of bottom ash residues are generated in Flanders, out of which only 102 kT are utilized here, and the rest is exported or landfilled due to non-conformity to environmental regulations. Landfilling makes the valuable resources in the residues unavailable and results in more primary raw materials being used, increasing mining and related hazards. Identifying and employing the right pre-treatment technique for the highest value application is the key to attaining a circular economy. We reviewed the present pre-treatment and utilization scenarios in Belgium, and the advancements in research around the world for realization of maximum utilization are reported in this paper. Uses of the material in the cement industry as a binder and cement raw meal replacement are identified as possible effective utilization options for large quantities of bottom ash. Pre-treatment techniques that could facilitate this use are also discussed. With all the research evidence available, there is now a need for combined efforts from incineration and the cement industry for technical and economic optimization of the process flow., Competing Interests: The authors declare no conflict of interest.

Formation of cracks impairs the durability of concrete elements. Corrosion inducing substances, such as chlorides, can enter the matrix through these cracks and cause steel reinforcement corrosion and concrete degradation. Self-repair of concrete cracks is an innovative technique which has been studied extensively during the past decade and which may help to increase the sustainability of concrete. However, the experiments conducted until now did not allow for an assessment of the service life extension possible with self-healing concrete in comparison with traditional (cracked) concrete. In this research, a service life prediction of self-healing concrete was done based on input from chloride diffusion tests. Self-healing of cracks with encapsulated polyurethane precursor formed a partial barrier against immediate ingress of chlorides through the cracks. Application of self-healing concrete was able to reduce the chloride concentration in a cracked zone by 75% or more. As a result, service life of steel reinforced self-healing concrete slabs in marine environments could amount to 60-94 years as opposed to only seven years for ordinary (cracked) concrete. Subsequent life cycle assessment calculations indicated important environmental benefits (56%-75%) for the ten CML-IA (Center of Environmental Science of Leiden University-Impact Assessment) baseline impact indicators which are mainly induced by the achievable service life extension.

Given their low tensile strength, cement-based materials are very susceptible to cracking. These cracks serve as preferential pathways for corrosion inducing substances. For large concrete infrastructure works, currently available time-consuming manual repair techniques are not always an option. Often, one simply cannot reach the damaged areas and when making those areas accessible anyway (e.g., by redirecting traffic), the economic impacts involved would be enormous. Under those circumstances, it might be useful to have concrete with an embedded autonomous healing mechanism. In this paper, the effectiveness of incorporating encapsulated high and low viscosity polyurethane-based healing agents to ensure (multiple) crack healing has been investigated by means of capillary absorption tests on mortar while monitoring the time-dependent water ingress with neutron radiography. Overall visual interpretation and water front/sample cross-section area ratios as well as water profiles representing the area around the crack and their integrals do not show a preference for the high or low viscosity healing agent. Another observation is that in presence of two cracks, only one is properly healed, especially when using the latter healing agent. Exposure to water immediately after release of the healing agent stimulates the foaming reaction of the polyurethane and ensures a better crack closure.

Nowadays, more efforts towards sustainability are required from the concrete industry. Replacing traditional aggregates by recycled bottom ash (BA) from municipal solid waste incineration can contribute to this goal. Until now, only partial replacement has been considered to keep the concrete workability, strength and durability under control. In this research, the feasibility of a full aggregate replacement was investigated for producing prefabricated Lego bricks. It was found that the required compressive strength class for this purpose (C20/25) could be achieved. Nevertheless, a thorough understanding of the BA properties is needed to overcome other issues. As BA is highly absorptive, the concrete's water demand is high. This workability issue can be dealt with by subjecting the fine BA fraction to a crushing operation to eliminate the porous elements and by pre-wetting the fine and coarse BA fractions in a controlled manner. In addition, a reactive NaOH washing is needed to avoid formation of longitudinal voids and the resulting expansion due to the metallic aluminum present in the BA. Regarding the long-term behavior, heavy metal leaching and freeze-thaw exposure are not problematic, though there is susceptibility to acetic and lactic acid attack and maybe increased sensitivity to alkali-silica reaction.

Since the construction sector uses 50% of the Earth's raw materials and produces 50% of its waste, the development of more durable and sustainable building materials is crucial. Today, Construction and Demolition Waste (CDW) is mainly used in low level applications, namely as unbound material for foundations, e.g., in road construction. Mineral demolition waste can be recycled as crushed aggregates for concrete, but these reduce the compressive strength and affect the workability due to higher values of water absorption. To advance the use of concrete rubble, Completely Recyclable Concrete (CRC) is designed for reincarnation within the cement production, following the Cradle-to-Cradle (C2C) principle. By the design, CRC becomes a resource for cement production because the chemical composition of CRC will be similar to that of cement raw materials. If CRC is used on a regular basis, a closed concrete-cement-concrete material cycle will arise, which is completely different from the current life cycle of traditional concrete. Within the research towards this CRC it is important to quantify the benefit for the environment and Life Cycle Assessment (LCA) needs to be performed, of which the results are presented in a this paper. It was observed that CRC could significantly reduce the global warming potential of concrete.