•Multiple recycling properties of recycled aggregate has been analysed.•Computerized micro-tomography identifies phases of the recycled aggregate.•After 3 recycling the volume of adhered mortar is ...80% of the aggregate.•Density decreases with recycling cycles and the size of the aggregate.
This paper presents a novel technique used to analyse the volume of adhered mortar to the recycled aggregate. A computerized microtomograph (μCT) device was used to evaluate the volume of the aggregate, the volume of natural aggregate and the volume of adhered mortar. To this end, a natural aggregate has been characterized, using the μCT, with which a source concrete has been produced. Subsequently, the source concrete has been crushed to obtain a first cycle recycled aggregate. After the characterization of the first-generation of recycled aggregate, a new source concrete has been made with it to be subsequently crushed again obtaining a second-generation recycled aggregates. In the same way a third-generation recycled aggregate has been obtained and has been equally characterized. The results show that the compaction capacity of the aggregate is reduced after successive recycling. It has been possible to quantify how much the closed porosity of the recycled aggregate decreases with the number of times it is recycled. The loss of natural aggregate and increase of the volume of adhered mortar have also been evaluated using this technique.
•Incorporation of fine sanitary ware aggregates in coating mortars.•Extensive experimental program on the mechanical, durability and water-related properties of these mortars.•Almost all properties ...improved with the incorporation of fine sanitary ware aggregates.•Prospective applications include brick laying, masonry pointing or masonry repair mortars.
This paper analyses the behaviour of cement mortars with addition of grinded fine sanitary ware (GSWF) aggregates, in percentages of 0%, 10%, 15% and 20% of the natural aggregates’ volume, to be used as renderings.
The effect of these recycled materials was studied in an experimental programme through several tests. The performance of these modified mortars was evaluated in terms of strength, water absorption, water retention, dimensional instability and water permeability. Some extra tests were also formulated to understand the microstructure of these mortars such as open porosity and magnifying glass observation.
The research results were very positive since the modified mortars had, in the most tests, better performance than the reference mortar (0% of GSWF addition). The modified mortar with 20% addition of GSWF was the one with the best performance of all the modified mortars, in particular in terms of higher strength and lower water absorption.
•Review on the use of municipal incinerated bottom ashes in several applications.•Applications include geopolymers, adsorbents, ceramics, agriculture, and landfills.•MIBA presents compatibility with ...raw materials of ceramics and geopolymers.•Adequately treated, MIBA can be a low-cost adsorbent for wastewaters and gases.
This paper presents a literature review on the incorporation of municipal solid waste incinerated bottom ash as raw material in several markets, other than those where it is conventionally used, such as geotechnical applications and road pavement construction. The main findings of an ample selection of experimental investigations on the use of the bottom ash as precursor of alkali-activated materials, as an adsorbent material for the removal of hazardous elements from wastewater and landfill gases, as soil replacement in agricultural activities, as partial or complete substitute of raw materials for the manufacture of ceramic-based products, as landfill cover and as biogas production enhancer, were gathered, collated and analysed.
•Marble quarrying produces huge volumes of waste that is simply dumped.•Concrete mixes with 0%, 20%, 50% and 100% fine marble aggregates were tested for durability.•Results were compared with those ...of concrete with granite, basalt and river sand.•Fine marble aggregates proved to be suitable for structural concrete.
The aim of this research is to assess the durability performance of concrete containing various percentages of fine aggregates produced from the waste generated by the marble quarrying industry (0%, 20%, 50% and 100% of the total volume of fine aggregates). The workability and bulk density of fresh concrete were measured and the water absorption by capillary action and immersion, together with the carbonation, chloride penetration and drying shrinkage of hardened concrete, were determined.
It was concluded that the durability properties of concrete containing fine aggregates of granite, basalt and river sand tend to improve, remain constant and decrease, respectively, with the incorporation of fine aggregates from marble quarrying waste. However, these changes do not compromise the use of these secondary aggregates in structural concrete.
•This article optimizes the mechanical stabilization capacity of EAFD using currently available mortars.•The EAFD hinders the hydration process of tricalcium silicate in cement mortars.•Mortars with ...EAFD have a double hydrated hydroxide of Ca and Zn instead of portlandite.•A maximum mass ratio of 6.67kg EAFD per kg of cement was mechanically stabilized.•This is the highest EAFD/cement ratio ever used to mechanically stabilize this type of hazardous waste.
This article shows the results of an experimental study carried out in order to determine the maximum amount of electric arc furnace dust (EAFD) that can be incorporated into fluid cement-based mortars to produce mechanically stable monolithic blocks. The leaching performance of all mixes was studied in order to classify them according to the EU Council Decision 2003/33/EC. Two mortars were used as reference and three levels of EAFD incorporation were tested in each of the reference mortars. As the incorporation ratio of EAFD/cement increases, the mechanical strength decreases. This is due to the greater EAFD/cement and water/cement ratios, besides the presence of a double-hydrated hydroxide of Ca and Zn (CaZn2(OH)6·2H2O) instead of the portlandite phase (Ca(OH)2) in the mixes made with EAFD, as well as non-hydrated tricalcium silicate. A mass ratio of 2:1 (EAFD: cement-based mortar) can be added maintaining a stable mechanical strength. The mechanical stabilization process also reduced the leaching of metals, although it was not able to reduce the Pb concentration below the limit for hazardous waste. The high amount of EAFD mechanically stabilized in this experimental study can be useful to reduce the storage volume required in hazardous waste landfills.
► The performance of mortar manufactured using ceramic aggregates was evaluated. ► Five mortars were tested with different replacement ratios of 0%, 5%, 10%, 20% and 40%. ► The aggregates were ...replaced by volume. ► Replacement ratios of up to 40% do not affect the properties of mortar. ► The use of ceramic aggregates in masonry mortar manufacturing is a viable alternative to current practice.
This paper evaluates the performance of fresh and hardened masonry mortar manufactured using fine recycled aggregate from ceramic partition wall rubble. Five mortars were prepared replacing 0%, 5%, 10%, 20%, and 40% of the natural sand by fine recycled aggregate. A 1:7 volumetric cement-to-aggregate ratio was used. The data were analysed using a one-way analysis of variance and the results showed that replacement ratios of up to 40% by volume did not significantly affect the properties of fresh and hardened mortar, with the exception of density and workability. Therefore, the use of fine recycled aggregates in masonry mortar manufacturing could be a viable alternative that would help increase the recycling rate of construction and demolition waste and support sustainable development in the building sector.
Introduction
Transcranial Magnetic Stimulation (TMS) is a non-invasive neuromodulation tool with a growing body of clinical evidence demonstrating positive outcomes in patients with ...treatment-resistant depression (TRD) as sole or adjuvant therapy. Theta-burst stimulation (TBS), specifically intermittent TBS (iTBS), uses short intermittent pulse trains to cut each session’s duration to 10% of the original repetitive TMS protocol sessions, making it a more appealing option given that it shows similar efficacy. Nevertheless, the number of sessions required remains the same, with a single protocol lasting around 4 to 6 weeks, or longer. However, a new protocol has very recently been approved by the FDA for application in TRD, called the SAINT (Stanford Intelligent Accelerated Neuromodulation Therapy), which reduces treatment duration to 5 days.
Objectives
To ascertain what evidence supports the SAINT protocol and its efficacy by reviewing available published literature.
Methods
A PubMed database search was performed and the main findings of selected studies were summarized.
Results
Three articles were found, which consisted of clinical trials with small study samples of TRD patients. One study found a 90% remission rate after the aforementioned 5-day treatment regimen, with another reporting a 79% response rate after a double-blinded trial. All studies reported no difference in tolerability compared with regular iTBS protocols.
Conclusions
The SAINT protocol shows promising preliminary results, with efficacy, tolerability and safety of use comparable with that of TMS protocols already in use. The reduction in treatment duration that this intensive option is based on is a significant improvement for applicability in clinical practice, which might increase patient compliance and offer quicker results. Further studies are required to evaluate whether the remission rates are maintained in the long term.
Disclosure of Interest
None Declared
Information on the effects of incorporating fine recycled ceramic aggregates on concrete's durability is very scarce. This paper presents an experimental study using aggregates sourced from crushed ...red clay ceramic bricks (CBAs) and sanitary ware (SWA). Different concrete mixes were produced where the fine natural aggregate fraction was partially or fully replaced (20%, 50% and 100%, by volume) by each of these materials. Shrinkage, water absorption by immersion, water absorption by capillary action, carbonation and chloride ion penetration tests were carried out. Results show that using fine CBA provides better performance in terms of water absorption by capillarity and chloride ion penetration, contrarily to shrinkage, water absorption by immersion and carbonation penetration. Using fine SWA leads to a similar performance in terms of shrinkage, but all other properties are significantly and detrimentally affected. Notwithstanding the increased water requirement due to the high absorption capacity of CBA and the formation of agglomerated particles with SWA, this paper shows that a judicious use of these materials may allow the production of adequate structural concrete; in mixes with SWA the use of superplasticizers is a very effective approach in preventing the formation of clusters, even providing a better performance than the control concrete.
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•Concrete produced with fine aggregates from crushed ceramic bricks and sanitary ware•Great cohesive forces were found in fine SWAs’ vitreous surfaces•Concrete with fine CBA exhibited better performance in terms of permeability•Specimens with increasing fine CBA content exhibited pozzolanic activity•The use of fine SWA leads to a similar performance in terms of shrinkage
Currently, the scientific community has almost reached a consensus on the negative impacts of climate change. The causes of global warming are negative for sure, but are the impacts of these new ...climatic conditions negative and relevant? The answer is again probably yes, but not necessarily so. This study intends to evaluate the impacts of climate change on the functional deterioration of heritage buildings located in South Chile. For this purpose, an advanced artificial intelligence methodology, based on fuzzy logic, is used, and 79 heritage buildings, in five locations in South Chile, are analysed. The results obtained revealed that the predictions of climate change for this region, with an expected increase in temperature, associated with a reduction of the average annual precipitation, for the period 2045–2069, could actually benefit the functional performance of the heritage buildings analysed. Some lessons could be learned from the results, and the proposed model could be used for the prioritisation of maintenance activities, in heritage buildings, for the different locations analysed, considering the expected effect of climate changes, which in many other cases can be detrimental.
•This study analyses the impacts of climate change on heritage buildings in Chile.•A total of 79 heritage buildings in South Chile are analysed.•The climate change projections in South Chile correspond to the period 2020–2069.•Climatic effects on the functional service life of these buildings are evaluated.
Window frames are an important element of buildings, with an enormous impact on the thermal performance and interior comfort conditions of buildings. Knowledge regarding the service life of window ...frames is extremely relevant, aiding the adoption of adequate solutions in the design and maintenance stages. This study proposes a methodology for the service life prediction of window frames, based on the visual inspection of 182 case studies, in-use conditions, in which the degradation phenomena and various characteristics of window frames are surveyed. This information is converted into degradation curves, which express the evolution of the degradation of window frames over time, allowing their service life to be estimated, as well as the influence of their characteristics on their durability. For aluminum and wooden frameworks, estimated service lives of 37.6 and 27.3 years are obtained. These results reveal that the window exposure conditions and the users' behaviors have a substantial impact on the degradation of window frames.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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