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Serviceability behavior of Normal Strength Concrete (NSC) and High Strength Concrete (HSC) T-beams was experimentally evaluated. The crack pattern was observed, the effect of flange dimensions (breadth and thickness) on the crack pattern and load-deflection response was evaluated experimentally for 10 beams comprising the two studied groups, NSC and HSC T-beams. The short-term deflections were measured experimentally and predicted empirically under mid-span concentrated loading. It was found that increasing the flange width and thickness resulted in higher loads and lower deflections under service loads to a different extent. Prior to failure, the increment in the maximum loads was up to 22% while the deflection reduced by 31% for NSC and 23% for HSC beams. The available equations for determining the effective moment of inertia (Ie) were reviewed and used in predicting the Ie of the cracked beam. The results were compared with the experimental values (Iexp). The Ie showed a noticeable difference, especially for the HSC T-beams. New equations were proposed in which the tensile reinforcement ratio was considered. Compared with the other available equations, the proposed equations demonstrated a better agreement and repeatability of predicting experimental results studied herein. In addition, the proposed equations were used to predict the Ie for experimentally tested T-beams available in the literature. The proposed models showed a high degree of accuracy.

There is a global outcry over the speedy deterioration of structures in oil and gas facilities. While marine environment is considered the leading factor in the deterioration of offshore structures, there is no single factor considered as the main cause of the problem in onshore structures. Therefore, the aim of this paper is to present the result of global survey on the major factors causing the deterioration of concrete structures in onshore oil and gas facilities. To realize the objectives of the paper, an e-questionnaire was administered through two International LinkedIn groups with a membership mainly dominated by experts in onshore oil and gas facilities. 159 respondents completed the questionnaires, and the reliability of the responses was calculated to be 0.950 which is considered excellent. Relative importance index was used in ranking the factors, and it was observed that environmental factors ranked as the dominant factors causing the deterioration of concrete structures in onshore process plants. Another important finding in the study is the role that experience plays on the perception of experts on the causes of defects on concrete structures.

This paper reports the results of the laboratory tests conducted to investigate the effect of sodium hydroxide concentration on the fresh properties and compressive strength of self-compacting geopolymer concrete (SCGC). The experiments were conducted by varying the concentration of sodium hydroxide from 8 M to 14 M. Test methods such as Slump flow, V-Funnel, L-box and J-Ring were used to assess the workability characteristics of SCGC. The test specimens were cured at 70°C for a period of 48 hours and then kept in room temperature until the day of testing. Compressive strength test was carried out at the ages of 1, 3, 7 and 28 days. Test results indicate that concentration variation of sodium hydroxide had least effect on the fresh properties of SCGC. With the increase in sodium hydroxide concentration, the workability of fresh concrete was slightly reduced; however, the corresponding compressive strength was increased. Concrete samples with sodium hydroxide concentration of 12 M produced maximum compressive strength.