Brucellosis in ruminants in two counties of Yunnan, China and the use of an integrated approach for effective control

Brucellosis is an increasing production and public health concern in many countries of Asia including China. Challenges for an effective control include lack of collaboration between sectors or uncontrolled animal movement (among others). Yunnan might be at particular risk as ruminants are increasingly introduced from other parts of China e.g. Inner Mongolia, a known high prevalence area in a response to a higher demand for milk. To face this challenges, new integrated approaches are needed such as Ecohealth to support transdisciplinary collaboration versus silo thinking, the latter rather common in the top down animal health control system of China. In the presented research, which was part of an IDRC funded ILRI-Ecozd project, veterinary, public health, animal science experts from five provincial institutions, practitioners from the project sites, and policy authorities worked together to achieve a more effective control of brucellosis. The research was carried out between 2011 and 2013 in two counties of Yunnan, Mangshi and Yiliang and consisted of a historical data review, biological sampling (milk) in herds/households with dairy ruminants and people at risk (serum). Questionnaires were used to collect management data (N=192) from farmers; focus group discussions (villagers) and in depth interviews (village vets and human doctors) gained information on perception and awareness on zoonoses in general and more specifically on the targeted disease. Results from the biological sampling indicate brucellosis as an existing and potentially emerging public health concern depending on the production system. Risk factors for the spread of brucellosis were reported and included risky handling of aborted fetus among others. Awareness and perception on zoonoses (including brucellosis) of all interviewed groups was in general low. The use of a “learning by doing” EcoHealth approach led to improve team member's capacity on Ecohealth and its practical realisation in a field study, e.g. by building up collaboration between those institutions but also stakeholders. Crucial was the support by the Agriculture Department and Health Department of Yunnan. Outcome mapping indicated a change of behaviour in the targeted groups in particular on zoonoses knowledge and willingness to share of information between sectors (vet and public health)

Advanced progress in recycling municipal and construction solid wastes for manufacturing sustainable construction materials

The sharply increasing solid waste generation has raised the environmental concerns worldwide which currently have been escalated to a worrying level. Intending to eliminate the negative environmental impacts of solid waste and meanwhile promote sustainability on the energy- and resource-intensive construction and building sector, considerable efforts have been devoted to recycling solid waste for the possible use in sustainable construction material products. This paper reviews the existing studies on recycling municipal and construction solid waste for the manufacture of geopolymer composites. Special attention is paid to the predominate performance of these geopolymer composite products. The principal findings of this work reveal that municipal and construction solid waste could be successfully incorporated into geopolymer composites in the forms of precursor, aggregate, additive, reinforcement fiber, or filling material. Additionally, the results indicate that although the inclusion of such waste might depress some of the attributes of geopolymer composites, proper proportion design and suitable treatment technique could alleviate these detrimental effects and further smooth the recycling progress. Finally, a brief discussion is provided to identify the important needs in the future research and development for promoting the utilization of solid waste materials in the forthcoming sustainable geopolymer industry. In summary, this work offers guidance for the better ecological choice to municipal and construction solid waste through developing waste materials into highly environmental-friendly construction materials

Effect of raw materials on the performance of 3D printing geopolymer: A review

Traditional construction materials such as cement products release a significant amount of carbon dioxide during their preparation and usage, negatively impacting on the environment. In contrast, 3D printing (3DP) with geopolymer materials utilises renewable and low-carbon emission raw materials. It also exhibits characteristics such as energy efficiency and resource-efficient utilisation, contributing to reduction in carbon emissions and an improvement in sustainability. Therefore, the development of 3DP geopolymer holds great significance. This paper provides a comprehensive review of 3DP geopolymer systems, examining the effect of raw materials on processability, including flowability and thixotropy, and microstructure. The study also delves into sustainability and environmental impact. The evaluation highlights the crucial role of silicon, aluminium, and calcium content in the silicate raw material, influencing the gel structure and microstructural development of the geopolymer. Aluminium promotes reaction rate, increases reaction degree, and aids in product formation. Silicon enhances the mechanical properties of geopolymer, while calcium facilitates the formation and stability of the three-dimensional network structure, further improving material strength and stability. Moreover, the reactivity of raw materials is a key factor affecting interlayer bonding and interface mechanical properties. Finally, considering sustainability, the selection of raw materials is crucial in reducing carbon emissions, energy consumption, and costs. Compared to Portland cement, 3DP geopolymer material demonstrate lower carbon emissions, energy consumption, and costs, thus making it a sustainable material

Integral waterproof concrete : a comprehensive review

The ingress of water and aggressive substances is the primary reason for the chemical and physical degradation of concrete infrastructure, leading to a reduction in durability and a shortening of life span. In practice, different integral waterproofing admixtures and surface coatings have been widely used to prevent or mitigate this problem. Compared with surface protection, the incorporation of integral waterproofing admixtures (such as densifiers, water repellents, and crystalline admixtures) in concrete has several benefits, such as ease of application, elimination of regular maintenance, and little or no deterioration over time. So far, there is no comprehensive review on integral waterproofing admixtures and their effects on various properties of concrete. This review examines existing literature on integral waterproof concrete containing various commercial and laboratory-made waterproofing admixtures. This comprehensive review highlights that the use of integral waterproofing admixtures has the potential to increase the service life and improve the durability of concrete structures and infrastructure. However, the admixtures may have a negative impact on some concrete properties, such as workability and strength. Whilst many hydrophobic and crystalline admixtures can reduce the water absorption rate of concrete by up to 80%, they often have a negative impact on the concrete compressive strength, causing a strength reduction of about 10% or more. Their influence on some durability properties (e.g., reinforcement corrosion, microbial-induced concrete corrosion) is inconclusive, indicating the need for further research. There is also a need to develop proper guidelines to determine the efficacy of integral waterproofing admixtures. More research is also required to assess the long-term performance of integral waterproof concrete and its benefits based on life cycle assessment

CO2 concrete and its practical value utilising living lab methodologies

The sequestration of carbon dioxide into recycled aggregates for the enhancement of recycled aggregate concrete has provided an abundance of potential over recent years. The injection of carbon dioxide creates a strong concrete, known as CO2 Concrete, which can rival virgin aggregate concrete in overall performance. However, previous research only delves into small-scale testing. This paper demonstrates the potential for CO2 Concrete to be used in large-scale practical applications through living lab methodology. The compressive strength of CO2 Concrete offers great potential. After the carbon-conditioning of aggregate, the recycled aggregate concrete achieved the 95.1% strength when compared to the virgin aggregate concrete. Furthermore, it greatly surpassed the untreated recycled aggregate concrete which only exhibited a compressive strength of 64.76% when compared to the virgin aggregate concrete. This trend is also demonstrated by the two living lab projects. The living labs project consisted of two biosecurity platforms with a size of 780 mm long, 560 mm wide and 120 mm deep as well as four cattle drinking station slabs with a size of 3 m in length, 2.6 m in width and 0.2 m in thickness for agricultural use for Hawkesbury Campus, Western Sydney University. The biosecurity platforms are used for the cleaning of boots between paddocks in order to prevent the spread of disease whilst the slabs are utilised for the support of cattle drinking basins and to retain a desirable ground level, which would normally be eroded by cattle. The living labs achieved an outstanding 28-day compressive strength even surpassing virgin aggregate concrete on some occasions. The labs also demonstrated great durability. The employment of non-destructive testing shows the CO2 Concrete can preserve compressive strength under harsh agriculture conditions, which can include chemical attack, cattle movement and heavy machinery loading. After over a year and a half of practical application, the biosecurity platforms have not experienced depreciation according to the non-destructive testing. Visual inspections also reveal minimal degradation with only the sharp edges of the bio-security platforms rounding over after a year and a half. The overall performance of CO2 Concrete is outstanding and has the potential to replace the typical virgin aggregate concrete

Synergistic effects of polypropylene and glass fiber on mechanical properties and durability of recycled aggregate concrete

To better understand the synergistic effects of combined fibers on mechanical properties and durability of recycled aggregate concrete (RAC), different types of fibers with various lengths and mass ratios were adopted in this study. Experimental investigations were conducted to study the 28-day compressive strength and strength loss after exposed to salt-solution freeze–thaw cycles and the coupled action of mechanical loading and salt-solution freeze–thaw cycles. The microstructure was also characterized to evaluate the mechanism of this synergistic effect. To determine the effectiveness of the combined fibers on improving the mechanical properties and durability of RAC, the synergistic coefficient was proposed and applied for various combinations of fibers. The results indicate that the incorporation of fibers slightly decreased the 28-day compressive strength of RAC, but combining different sizes and types of fibers can mitigate this negative effect. Moreover, the incorporation of fibers greatly improves the freeze–thaw resistance of RAC. The combining different fibers exhibited a synergistic effect on the enhancement in properties of RAC, which could not be predicted with only one simplistic rule of fibre mixtures. In addition, microstructural characterization shows that the bonding strength of the interfacial transition zone (ITZ) between the fiber and cement matrix is mainly determined by the chemical bonding force which is due to the hydration reaction between fiber surface and cement matrix

Comparative investigation on nanomechanical properties of hardened cement paste

Three types of nanomechanical methods including static nanoindentation, modulus mapping and peak-force quantitative nanomechanical mapping (QNM) were applied to investigate the quantitative nanomechanical properties of the same indent location in hardened cement paste. Compared to the nanoindentation, modulus mapping and peak-force QNM allow for evaluating local mechanical properties of a smaller area with higher resolution. Beside, the ranges of elastic modulus distribution measured by modulus mapping and peak-force QNM are relatively greater than that obtained from nanoindentation, which may be due to a result of the shaper probe and local confinement effect between multiple phases. Moreover, the average value of elastic modulus obtained using peak-force QNM were consistent with those obtained by modulus mapping, while the different in modulus probability distribution could be related to the different nanomechancial theories and contact forces. The probability distributions of elastic modulus measured using nanomechanical methods to provide a basis for the different types of phases existing in cement paste. Based on the observation with high spatial resolution, cement paste can be likely found as nanocalse granular material, in which different submicron scale or basic nanoscale grain units pack together. It indicates that the peak-force QNM can effectively provide an effective insight into the nanostructure characteristic and corresponding nanomechanical properties of cement paste

Vertical Bearing Capacity of Precast Pier Foundation Filled with Demolished Concrete Lumps

The application of recycled compound concrete made of demolished concrete lumps (DCLs) and fresh normal concrete in pier foundation can effectively improve the utilization efficiency of construction waste resources. In this study, two prefabricated pier foundations based on recycled compound concrete (dimension of Ø800 × 2500 mm and Ø1000 × 2500 mm) and two cast-in-place pier foundations based on ordinary concrete (dimension of Ø800 × 2500 mm and Ø1000 × 2500 mm) were tested. Special attention was devoted to the load-settlement curve characteristics of the precast pier foundation of compound concrete, the load transfer law of the pier-soil system, the soil pressure distribution at the bottom of the pier, and the failure mode. The results showed that the Q-S curve of precast concrete pier foundation made of recycled compound concrete is slow deformation at loading, which is consistent with that of cast-in-place concrete pier foundation. The load transfer theory of pier-soil system is established, and its accuracy is verified by experimental analysis. The precast foundation of recycled compound concrete is the same as the cast-in-place foundation of ordinary concrete. The failure form of prefabricated pier foundation made of recycled compound concrete was a local shear failure, while the failure form of ordinary concrete cast-in-place pier foundation was piercing-type shear failure. The feasibility of relevant theoretical methods for calculating the vertical ultimate bearing capacity is examined