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Many hydraulic structures exhibit downstream cracks and surface degradation due to porous and non air-entrained concrete cast only a few decades ago, wetting–drying and freezing–thawing cycles. These degradations could be prevented by minimizing surface saturation and water infiltration by sealing the concrete surface. Many different types of sealers, such as silanes, siloxanes, boiled linseed oil, epoxies, urethanes and cement-based products, are presently available on the market. However, despite their ready availability, very few or no laboratory or field evaluations have ever been undertaken to evaluate their effectiveness, specifically for hydraulic structures exposed to extremely low temperatures. Consequently, 60 different surface sealers were selected for laboratory evaluation, aimed at minimizing water or moisture infiltration, and to extend the service life of hydraulic structures, besides reducing the harmful effects associated with concrete surface deterioration. The tests carried out on these sealers comprised reduction of absorption and evaporation capacity, durability under freezing–thawing and wetting–drying cycles, acid rain, UV radiation, effect of various parameters, such as concrete water:cement ratio (W/C), sealers application temperature, pH variation, presence of hydrostatic pressure, etc. Preliminary data showed that silanes and siloxanes exhibited satisfactory results, however, products from the same family yielded variable results. This paper summarizes a part of a large study on concrete sealers for hydraulic structures in cold climates.

Envelope air tightness is one factor that has impact on the energy performance of buildings. The goals of the directive 2010/31/EU, on energy performance of buildings, raise the importance of building energy performance analysis in the process. Measurements of air tightness can be useful both when evaluating building energy performance and developing new building techniques. The aim of this paper is to review and evaluate methods to measure air tightness in both new and existing residential buildings in Sweden, Norway and Finland, based on an international literature study and a survey. The methods are categorized based on a number of criteria to determine their suitability in different situations. Advantages and disadvantages of the methods are discussed, as well as commonly used methods in the three countries. The review shows that the standard ISO 9972 is used for verification in all three countries, but alternatives exist that might be more suitable in certain situations. Simpler methods are used in the building process to increase air tightness. To achieve a comparable measurement, both common methods and commonly defined units are needed.

The paper discusses the work carried out over the past 7 years within RILEM Technical Committee 190-SBJ Service Life Prediction of Sealed Building and Construction Joints towards the development of RILEM Technical Recommendations (RTR) on durability test methods for wet-applied (gun-grade) curtain-wall sealants. This paper is published along with the two draft RTR methods to provide some insight into the discussions within the committee during the development and early evaluation of both methods. The two draft RTR methods define test and evaluation protocols for accelerated artificial weathering and natural outdoor weathering. Both draft RTR methods are based on a novel test specimen configuration that allows simultaneous exposure of the sealant to compression and extension during movement cycles. Because of the special test joint configuration, the sealant is exposed to variable extension and compression amplitudes along the joint axis, allowing an evaluation of the effect of different movement amplitudes on the sealant when taking weatherability considerations into account. The results of the initial evaluations indicate that the test methods are capable of differentiating between products with regard to their resistance to accelerated or outdoor weathering and mechanical cycling. The type of failure and the changes in surface appearance observed during the test regimes are similar to those observed in actual service conditions. It is hoped that exposure studies based on these two new RTR methods will provide the underpinnings for the development of future ISO and ASTM durability test standards for building sealants.

Firstly, a background of past studies on Roman amphorae sealing systems is presented. However, apart from the consensus regarding the use of vegetable resins, some questions remain unanswered. On this study the use of resins as sealing material is detected, as well as other components which are added to resins and remarkably improve the features of the mixture, whose essential requirement was to provide effective sealing for the ceramic container. The identification of calcic soaps on the inner part of amphorae reveals the addition of oil and lime on the sealing mix.