This present study benchmarked the chloride resistance of concretes mixes at the limit state of BS 8500-1:2006 using the newly published CEN TS12390-11. Of the three allowed methodologies, the immersion test was carried out. At least two water-cement ratios were produced for each mix design to enable normalisation of the results. The performance of concrete was compared on the basis of equal compressive strength, i.e. 40 and 50 N/mm2 and an equal water-cement ratio of 0.45. In addition to the CEN TS 12390-11:2010, rapid test methods NT Build 492 and a steady-state migration test UNE 83987:2009 were also conducted. Selected concretes were also tested for cyclic wetting in artificial sea water and evolution of chloride diffusion over the test period. The ageing factor of concrete mixes, which describes the development of diffusion coefficient (D) from the unsteady to steady-state determined from this research was compared with those reported in The Concrete Society Technical Report 61. Test specimens for highway exposure were also produced for future research work. CEN has just agreed and published (at the time of the writing of this thesis) a test methodology for chloride resistance as a technical standard (CEN, 2010). The test method underpins the equivalent durability performance approach. Therefore, the use of this test was investigated in terms of evolution of the chloride diffusion, and effect of cyclic wetting and drying in artificial seawater exposure. As the test method is slow, (3 months to complete), other rapid test methods were also studied on the same specimens. The results from these tests were compared to look for the possibility of having a faster test methodology for chloride durability. Overall, the results showed that concrete mixes at the limiting value of BS 8500-1:2006 have a wide range of performance between 0.3 × 10-12 m2/s and 20 × 10-12 m2/s regardless of the test methods. Ranking of concrete according to performance shows that this changes with age. This is the same for all test methods although the rate of change is different between different test methods. However, the ranking of concrete at equal compressive strength and equal water-cement ratio follows the general order of (from best to worst) ggbs> fly ash> silica fume> limestone> CEM I. It was also postulated that there is a limit to the benefit of reducing water-cement ratio to improve durability. This is because of at very low water cement ratio, concrete may develop autogenous cracking that is detrimental to the porosity. Using the CEN TS 12390-11:2010 it was found that CEM I, fly ash and silica fume mixes follows the same ageing factor proposed by Concrete Society Technical Report 61 although ggbs shows a different ageing factor. The improvement of ggbs quality was attributed to this change. It was also found that 90 days test duration was optimum as a shorter period risks giving a non stable diffusion rate whilst longer than 90 days shows insignificant change in Dnss values. Exposure of selected concrete specimens to cyclic wetting and drying in artificial seawater elevated to 1 M NaCl equivalent shows reduced chloride diffusion. However, the mechanism controlling this is not clear. The thesis showed that some of the limiting value requirement for BS 8500-1:2006 does not meet the durability requirements for chloride resistance. There are some concrete mixes recommended that performs poorly in testing. The research reported also provides further understanding of the new CEN TS 12390-11:2010 in terms comparative ranking of cements up to the point of comparative performance between other tests methods. Validation of the ageing factor for chloride durability is also provided as well as the need for updates in the age factor values due to changes in the nature of cements.

Modern software applications need to run on a variety of web and mobile platforms with diverse software and hardware-level features. Thus, developers of such software need to duplicate the testing and maintenance effort on a wide range of platforms. Often developers are not able to cope with this increasing demand and release software that is broken on certain platforms, thereby affecting a class of customers using such platforms. Hence, there is a need for automating such duplicate activities to assist the developer in coping with the ever increasing demand. The goal of my work is to improve the testing and maintenance of cross-platform web and mobile applications by developing automated techniques for comparing and matching the behavior of such applications across different platforms. To achieve this goal, I have identified three problems that are relevant in the context of cross-platform testing and maintenance: 1) automated identification of inconsistencies in the same application's behavior across multiple platforms, 2) detecting features that are present in the application on one platform, but missing on another platform version of the same application, and, 3) automated migration of test suites and possibly other software artifacts across platforms. I present three different scenarios for the development of {cross-platform} web and mobile applications, and formulate each of the three problems in the scenario where it is most relevant. To address and mitigate these problems in their corresponding scenarios, I present the principled design, development and evaluation of the two techniques, and a third preliminary technique to highlight the research challenges of test migration. The first technique, X-pert identifies inconsistencies in a web application running on multiple web browsers. The second technique, FMAP matches features between the desktop and mobile versions of a web application and reports any features found missing on either of the platform versions. The final technique, MigraTest attempts to automatically migrate test cases from a mobile application on one platform to its counterpart on another platform. To evaluate these techniques, I implemented them as prototype tools and ran these tools on real-world subject applications. The empirical evaluation of X-pert shows that it is accurate and effective in detecting real-world inconsistencies in web applications. In the case of FMAP, the results of my evaluation show that it was able to correctly identify missing features between desktop and mobile versions of the web applications considered, as confirmed by my analysis of user reports and software fixes for these applications. The third technique, MigraTest was able to efficiently migrate test cases between two mobile platform versions of the subject applications.