Based on the investigation of fiber influence on workability of self-compacting concrete (SCC), tests were carried out on two series of SCC rectangular simply supported beams, which were made of hooked steel fibers re...Based on the investigation of fiber influence on workability of self-compacting concrete (SCC), tests were carried out on two series of SCC rectangular simply supported beams, which were made of hooked steel fibers reinforced concrete with or without stirrups, subjected to four-point symmetrically placed vertical loads. The major test variables are steel fiber contents and stirrup ratios. The results indicate that the ultimate load significantly increases with the increase of fiber content; the addition of steel fibers in adequate percentage can change the failure mode from a brittle shear collapse into a ductile flexural mechanism. The stirrups can be partially replaced by steel fibers. The combination of stirrups and steel fibers demonstrated a positive hybrid effect on the mechanical behavior.展开更多
In the structures where long-term behavior should be monitored and controlled, creep and shrinkage effects have to be included precisely in the analysis and design procedures. Shrinkage varies with the constituent and...In the structures where long-term behavior should be monitored and controlled, creep and shrinkage effects have to be included precisely in the analysis and design procedures. Shrinkage varies with the constituent and mixture proportions, and depends on the curing conditions and the work environment as well. Self-compacting concrete (SCC) contains combinations of various components, such as aggregate, cement, superplasticizer, water-reducing agent and other ingredients which affect the properties of the SCC including shrinkage. Hence, the realistic prediction shrinkage strains of SCC are an important requirement of the design process for this type of concrete structures. This study reviews the accuracy of the conventional concrete (CC) shrinkage prediction models proposed by the international codes of practice, including CEB-FIP (1990), ACI 209R (1997), Eurocode 2 (2001), JSCE (2002), AASHTO (2004; 2007) and AS 3600 (2009). Also, SCC shrinkage prediction models proposed by Poppe and De Schutter (2005), Larson (2007), Cordoba (2007) and Khayat and Long (2010) are reviewed. Further, a new shrinkage prediction model based on the comprehensive analysis on both of the available models, i.e., the CC and the SCC is proposed. The predicted shrinkage strains are compared with the actual measured shrinkage strains in 165 mixtures of SCC and 21 mixtures of CC.展开更多
基金Supported by National Natural Science Foundation of China (No. 50578026)
文摘Based on the investigation of fiber influence on workability of self-compacting concrete (SCC), tests were carried out on two series of SCC rectangular simply supported beams, which were made of hooked steel fibers reinforced concrete with or without stirrups, subjected to four-point symmetrically placed vertical loads. The major test variables are steel fiber contents and stirrup ratios. The results indicate that the ultimate load significantly increases with the increase of fiber content; the addition of steel fibers in adequate percentage can change the failure mode from a brittle shear collapse into a ductile flexural mechanism. The stirrups can be partially replaced by steel fibers. The combination of stirrups and steel fibers demonstrated a positive hybrid effect on the mechanical behavior.
文摘In the structures where long-term behavior should be monitored and controlled, creep and shrinkage effects have to be included precisely in the analysis and design procedures. Shrinkage varies with the constituent and mixture proportions, and depends on the curing conditions and the work environment as well. Self-compacting concrete (SCC) contains combinations of various components, such as aggregate, cement, superplasticizer, water-reducing agent and other ingredients which affect the properties of the SCC including shrinkage. Hence, the realistic prediction shrinkage strains of SCC are an important requirement of the design process for this type of concrete structures. This study reviews the accuracy of the conventional concrete (CC) shrinkage prediction models proposed by the international codes of practice, including CEB-FIP (1990), ACI 209R (1997), Eurocode 2 (2001), JSCE (2002), AASHTO (2004; 2007) and AS 3600 (2009). Also, SCC shrinkage prediction models proposed by Poppe and De Schutter (2005), Larson (2007), Cordoba (2007) and Khayat and Long (2010) are reviewed. Further, a new shrinkage prediction model based on the comprehensive analysis on both of the available models, i.e., the CC and the SCC is proposed. The predicted shrinkage strains are compared with the actual measured shrinkage strains in 165 mixtures of SCC and 21 mixtures of CC.
