1,721,375 research outputs found
Mechanical performance of different stabilised soils for application in stratified ground
No full textTo achieve homogeneity in soil mixing along the depth of a column in a non-homogeneous layered soils, it is necessary to understand the effect of soil type on the treatment and to adapt the treatment for the different soil strata. For this purpose, an extensive laboratory testing programme was carried out to examine the effect of different soils and cement content on the mechanical and physical properties of the resulting treated soils. Four different soils, namely gravely sand; silty clayey gravely sand, silty clay and a pure clay were tested. Different grout constituents, constituent ratios, dosages and water content were used in order to improve the performances of the mixes using Portland cement as the main binder. The tests performed included unconfined compressive strength, from which the elastic stiffness was also calculated, and permeability at 28 days. The results show that relatively homogenous results in terms of compressive strength and permeability may be reached by modifying the cement-bentonite ratio in granular soils and the binder dosage in fine-grained soils. The results constitute a preliminary useful guide to adapt in the construction techniques in field applications
Influence of curing temperature on the strength of cement stabilised artificial clays
No full textThe paper present results of a laboratory investigation on the influence of curing temperature and time on the mechanical characterisation of cement-stabilised clays as used in deep soil mix applications. Numerical modelling, based on the Arrhenius equation, is also presented. Experimentally, this model was applied to a series of tests performed at different temperatures. For each temperature, unconfined compressive strength tests were performed at specific time intervals in order to follow the curing and the increase of strength with time. The clay used was artificial clay made up of 40% kaolin clay and 60% of silt (using silica flour). Three different water contents were used to compare the performance of different soft clays. The results showed that the strength increases with the temperature. It was also found that the activation energy is the same for all three water content clays. Using the numerical modelling long-term behaviour of up to 2.4 years was predicted
Influence of moulding procedure, curing temperature and mixing time on the strength of cement stabilised artificial clays
No full textStrain Monitoring of Concrete Using Carbon Black-Based Smart Coatings
Full text linkGiven the challenges we face of an ageing infrastructure and insufficient maintenance, there is a critical shift towards preventive and predictive maintenance in construction. Self-sensing cement-based materials have drawn interest in this sector due to their high monitoring performance and durability compared to electronic sensors. While bulk applications have been well-discussed within this field, several challenges exist in their implementation for practical applications, such as poor workability and high manufacturing costs at larger volumes. This paper discusses the development of smart carbon-based cementitious coatings for strain monitoring of concrete substrates under flexural loading. This work presents a physical, electrical, and electromechanical investigation of sensing coatings with varying carbon black (CB) concentrations along with the geometric optimisation of the sensor design. The optimal strain-sensing performance, 55.5 ± 2.7, was obtained for coatings with 2 wt% of conductive filler, 3 mm thickness, and a gauge length of 60 mm. The results demonstrate the potential of applying smart coatings with carbon black addition for concrete strain monitoring
Impermeabilization of carbon black-based smart coatings for strain-sensing purposes
Full text linkThis study explores self-sensing properties in carbon black (CB)-based cementitious coatings, focusing on the influence of internal moisture on electrical measurements. Various saturation levels were examined by gradually drying the coatings and encapsulating them with epoxy resin to shield them from external humidity. Results show that inner water impacts the strain-sensing response of the coating, reaching an optimal moisture saturation of 25 % where an equilibrium between carbon black particles, water, and free ions was attained. For coatings on tension surfaces of concrete beams under flexural loads, 230.7 +/- 25.8 was the obtained gauge factor for 3 wt% added carbon black. Epoxy-sealing reduced the bonding strength between the coating and the substrate by 27 %. Nonetheless, epoxy-encapsulated coatings with 3 wt% carbon black achieved a gauge factor of 110.9 +/- 35.5, indicating a promising path for the production and application of self-sensing coatings that remain unaffected by external humidity conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
