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This paper presents a comparative environmental assessment of several different green concrete mixes for structural use. Four green concrete mixes were compared with a conventional concrete mix: recycled aggregate concrete with a cement binder, high-volume fly ash concrete with natural and recycled aggregates, and alkali activated fly ash concrete with natural aggregates. All five concrete mixes were designed and experimentally verified to have equal compressive strength and workability. An attributional life cycle assessment, based on the scenario which included construction practice, transport distances, and materials available in Serbia, was performed. When treating fly ash impacts, three allocation procedures were compared: 'no allocation', economic, and mass allocation, with mass allocation giving unreasonably high impacts of fly ash. Normalization and aggregation of indicators was performed and the impact of each concrete mix was expressed through a global sustainability indicator. A sensitivity analysis was also performed to evaluate the

An experimental study of the shear behavior of recycled aggregate concrete (RAC) beams with and without shear reinforcement is presented. Nine full-scale simply supported beams were loaded in fourpoint bending tests until failure. Three different replacement ratios of coarse natural with coarse recycled concrete aggregate (0%, 50%, and 100 %), and three different shear reinforcement ratios (0%, 0.14%, and 0.19 %) were the main parameters. All natural aggregate concretes (NAC) and recycled aggregate concretes (RAC) were designed and experimentally verified to have similar compressive strength and workability. It was found that the shear behavior and the shear strength of the beams with 50% and 100% of recycled concrete aggregate was very similar to that of the corresponding natural aggregate concrete beams. The applicability of different code provisions for the shear strength predictions of the RAC beams with and without shear reinforcement was tested by comparison to test results obtained on 85 beams, 58 RAC and 27 corresponding NAC beams. The shear strength of RAC50 and RAC100 beams with and without shear reinforcement was conservatively predicted by the analyzed codes with similar reliability as for the corresponding NAC beams shear strength. At this state-of-knowledge, the application of the analyzed codes' provisions for NAC beams shear strength can be recommended both for the RAC50 and the RAC100 beams. Highlights Nine full-scale NAC and RAC beams were tested until shear failure.  Similar shear behavior and strength of RAC and NAC beams.  Codes' provisions for the NAC beams shear strength can be also used for RAC beams.Abstract 1 An experimental study of the shear behaviour of recycled aggregate concrete (RAC) beams with and 2 without shear reinforcement is presented. Nine full-scale simply supported beams were loaded in four-3 point bending tests until failure. Three different replacement ratios of coarse natural with coarse 4 recycled concrete aggregate (0%, 50% and 100 %), and three different shear reinforcement ratios (0%, 5 0.14% and 0.19 %) were the main parameters. All natural aggregate concretes (NAC) and recycled 6 aggregate concretes (RAC) were designed and experimentally verified to have similar compressive 7 strength and workability. It was found that the shear behaviour and the shear strength of the beams 8 with 50% and 100% of recycled concrete aggregate were very similar to that of the corresponding 9 natural aggregate concrete beams. The applicability of different code provisions for shear strength 10 predictions of the RAC beams with and without shear reinforcement was tested by comparison with 11 test results obtained on 85 beams, 58 RAC and 27 corresponding NAC beams. The shear strength of 12 RAC50 and RAC100 beams with and without shear reinforcement was conservatively predicted by the 13 analyzed codes with similar reliability as for the corresponding NAC beams shear strength. At this 14 state-of-knowledge, the application of the analyzed codes' provisions for NAC beams shear strength...

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This paper describes a meta-analysis of previously published studies on the shrinkage strain of recycled aggregate concrete (RAC). The study aims at providing an analytic expression for the shrinkage strain of RAC to be used in conjunction with the existing fib Model Code 2010 shrinkage prediction model. For this purpose, a database of experimental results on the shrinkage of RAC and companion natural aggregate concrete (NAC), produced with the same water-cement ratio, was compiled using strict selection criteria. Results from 19 studies entered into the database, consisting of 125 shrinkage curves (39 NAC and 86 RAC) with a total of 424 data points. A comparison of RAC and companion NAC revealed that, on average, RAC displays a larger shrinkage strain. This difference increases with increasing recycled concrete aggregate (RCA) content and with decreasing compressive strength. Applying the fib Model Code 2010 shrinkage prediction model revealed that, relative to its performance on NAC, the shrinkage strain of RAC is underestimated. Finally, a correction coefficient for the shrinkage strain of RAC, ξ cs,RAC , to be used in conjunction with the fib Model Code 2010 model, was proposed in the form of a bivariate power function with RAC compressive strength and RCA replacement ratio as variables.

A two-phase experimental study on the effect of simultaneous partial replacement of cement and fine aggregate with fly ash on the mechanical and time-dependent properties of high-volume fly ash concrete (HVFAC) is presented. The results of the first phase of the study show that it is possible to make structural grade HVFAC with 50% of cement and an additional 30% of fine aggregate replacement that has a similar compressive strength to that of the control cement concrete and with adequate workability. In the second phase of the study the mechanical and time-dependent properties of HVFAC with a mass of fly ash of 50–70% of the total mass of cementitious materials were tested. The results show that with the increase in fly ash content the compressive strength of HVFAC increased by 22% on average at all ages tested. With the exception of the early-age compressive strength, it was found that the European standard EN 1992-1-1:2004 provisions for ordinary cement concrete underestimate the mechanical properties and significantly overestimate the shrinkage and creep of HVFAC. Better correlation with experimental results was obtained using different coefficients developed for HVFAC.

In order to provide a constant and complete operational picture of the maritime situation in the Exclusive Economic Zone (EEZ) at over the horizon (OTH) distances, a network of high frequency surface-wave-radars (HFSWR) slowly becomes a necessity. Since each HFSWR in the network tracks all the targets it detects independently of other radars in the network, there will be situations where multiple tracks are formed for a single vessel. The algorithm proposed in this paper utilizes radar tracks obtained from individual HFSWRs which are already processed by the multi-target tracking algorithm at the single radar level, and fuses them into a unique data stream. In this way, the data obtained from multiple HFSWRs originating from the very same target are weighted and combined into a single track. Moreover, the weighting approach significantly reduces inaccuracy. The algorithm is designed, implemented, and tested in a real working environment. The testing environment is located in the Gulf of Guinea and includes a network of two HFSWRs. In order to validate the algorithm outputs, the position of the vessels was calculated by the algorithm and compared with the positions obtained from several coastal sites, with LAIS receivers and SAIS data provided by a SAIS provider.