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Publication informationCement and Concrete Composites, 32 (7) AbstractThe costs associated with the provision and maintenance of drinking water and wastewater infrastructure represents a significant financial demand worldwide. Maintenance costs are disproportionately high, indicating a lack of adequate durability. There remains a lack of consensus on degradation mechanisms, the performance of various cement types, the role of bacteria in the corrosion process associated with wastewater applications and testing methodologies. This paper presents a review of the literature, outlining the various research approaches undertaken in an effort to address this problem. The findings of these varying approaches are compared, and the different strategies employed are compiled and discussed. It is proposed that a key step in advancing the understanding of the associated deterioration mechanism is a combined approach that considers the interaction between biological and chemical processes. If this can be achieved then steps can be taken to establishing a performance-based approach for specifying concrete in these harsh service conditions.

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Metals in agricultural structures are often subjected to adverse environmental conditions resulting in high corrosion rates (up to 200 m/yr). The di!erent factors enhancing metal corrosion in farm buildings include high humidity and temperature, high concentrations of aggressive gases, acids, and salts (from silage and feed residues, cleaning agents, manure, fertilizers, preservatives), mechanical destruction and bacteria causing microbially induced corrosion. The importance of microbially induced corrosion is not yet clari"ed and a reduction in corrosion by bio"lms on metals has also been reported. Corrosion products found in animal houses are similar to those resulting from classic corrosion mechanisms, which may lead to the conclusion that the fundamental mechanisms of metal corrosion in animal buildings are similar to the classic ones. Di!erent methods to detect, measure and predict corrosion are described. The economic losses by corrosion in agriculture are evaluated. By corrosion prevention, a reasonable amount of expense can be saved. Prevention includes: (1) the choice of corrosion resistant materials such as stainless steel or non-metallic materials; (2) designing against corrosion; (3) control of the aggressive environment; and (4) application of coatings. When protective coatings are used, such as zinc layers and painting systems, surface preparation of the metal is of the utmost importance. Zinc layers should be thick enough ( '50 m), and zinc-coated steel should be protected in areas of extreme aggressiveness, such as "ttings at #oor level. Reports about the durability of di!erent painting systems in agricultural structures are reviewed. The development of new environmentally friendly products is discussed. Guidelines for maintenance of previously painted steelwork are formulated. Silsoe Research Institute

<p><strong>Abstract.</strong> Quantifying forcings from anthropogenic perturbations to the Earth System (ES) is important for understanding changes in climate since the pre-industrial period. In this paper, we quantify and analyse a wide range of present-day (PD) anthropogenic climate forcings with the UK's Earth System Model (ESM), UKESM1, following the protocols defined by the Radiative Forcing Model Intercomparison Project (RFMIP) and the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP). In particular, by quantifying effective radiative forcings (ERFs) that include rapid adjustments within a full ESM, it enables the role of various climate-chemistry-aerosol-cloud feedbacks to be quantified.</p> <p>Global mean ERFs are 1.83, 0.13, −0.33, and 0.93 W m<sup>−2</sup> at the PD (Year 2014) relative to the pre-industrial (PI; Year 1850) for carbon dioxide, nitrous oxide, ozone-depleting substances, and methane, respectively. The PD total greenhouse gas ERF is 2.89 W m<sup>−2</sup>, larger than the sum of the individual GHG ERFs.</p> <p>UKESM1 has an aerosol forcing of −1.13 W m<sup>−2</sup>. A relatively strong negative forcing from aerosol-cloud interactions and a small negative instantaneous forcing from aerosol-radiation interactions are partially offset by a substantial forcing from black carbon absorption. Internal mixing and chemical interactions mean that neither the forcing from aerosol-radiation interactions nor aerosol-cloud interactions are linear, making the total aerosol ERF less than the sum of the individual speciated aerosol ERFs.</p> <p>Tropospheric ozone precursors, in addition to exerting a positive forcing due to ozone, lead to oxidant changes which in turn cause an indirect aerosol ERF, altering the sign of the net ERF from nitrogen oxide emissions. Together, aerosol and tropospheric ozone precursors (near-term climate forcers, NTCFs) exert a global mean ERF of −1.12 W m<sup>−2</sup>, mainly due to changes in the cloud radiative effect. There is also a negative PD ERF from land use (−0.32 W m<sup>−2</sup>). It is outside the range of previous estimates, and is most likely due to too strong an albedo response. In combination, the net anthropogenic ERF is potentially biased low (1.61 W m<sup>−2</sup>) relative to other estimates, due to the inclusion of non-linear feedbacks and ES interactions.</p> <p>By including feedbacks between greenhouse gases, stratospheric and tropospheric ozone, aerosols, and clouds, some of which act non-linearly, this work demonstrates the importance of ES interactions when quantifying climate forcing. It also suggests that rapid adjustments need to include chemical as well as physical adjustments to fully account for complex ES interactions.</p>

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