Fracture behavior is one of the most important,yet still little understood properties of ultra-high performance cementitious composites(UHPCC),a new marine structural engineering material. Research on the fracture and...Fracture behavior is one of the most important,yet still little understood properties of ultra-high performance cementitious composites(UHPCC),a new marine structural engineering material. Research on the fracture and direct tension behavior of UHPCC was carried out.The constitution law of UHPCC was divided into three phases:pre-partial debonding,partial debonding,and pullout phases.A direct tension constitution law was constructed based on the proposed fiber reinforcing parameter as a function of fiber volume fraction,fiber diameter and length,and fiber bonding strength.With the definition of linear crack shape,the energy release rate of UHPCC was derived and the R-curve equation was calculated from this.Loading tests of UHPCC using a three-point bending beam with an initial notch were carried out.The predictions from the proposed R-curve were in good agreement with the test results, indicating that the proposed R-curve accurately describes the fracture resistance of UHPCC.Introduction of a fiber reinforcement parameter bridges the fracture property R-curve and micro-composites’ mechanics parameters together.This has laid the foundation for further research into fracture properties based on micro-mechanics.The proposed tension constitution law and R-curve can be references for future UHPCC fracture evaluation.展开更多
Abstract： The purpose of this paper is to evaluate the suitability of using trass as a supplementary cementing material in pervious concrete. OPC （Ordinary Portland Cement） was replaced in the concrete mix by 15%, ...Abstract： The purpose of this paper is to evaluate the suitability of using trass as a supplementary cementing material in pervious concrete. OPC （Ordinary Portland Cement） was replaced in the concrete mix by 15%, 25% and 35% weight percentages and the results were compared with reference mixtures with 100% Portland cement. The variables in this study were trass content, aggregate size and water to cement ratio. Sixteen eases of concrete mixtures were tested to study physical and mechanical properties of hardened concrete, including porosity, permeability, compressive strength, splitting-tensile strength and flexural strength at various ages. Results indicated that mechanical properties of the pervious concrete marginally decreased with the increased content of trass when compared to the reference mixtures. However, at later ages the differences were insignificant.展开更多
基金the Center of Concrete Corea,Korea Development and Application of High Performance and Multi-Function Concrete(05-CCT-D11)
文摘Fracture behavior is one of the most important,yet still little understood properties of ultra-high performance cementitious composites(UHPCC),a new marine structural engineering material. Research on the fracture and direct tension behavior of UHPCC was carried out.The constitution law of UHPCC was divided into three phases:pre-partial debonding,partial debonding,and pullout phases.A direct tension constitution law was constructed based on the proposed fiber reinforcing parameter as a function of fiber volume fraction,fiber diameter and length,and fiber bonding strength.With the definition of linear crack shape,the energy release rate of UHPCC was derived and the R-curve equation was calculated from this.Loading tests of UHPCC using a three-point bending beam with an initial notch were carried out.The predictions from the proposed R-curve were in good agreement with the test results, indicating that the proposed R-curve accurately describes the fracture resistance of UHPCC.Introduction of a fiber reinforcement parameter bridges the fracture property R-curve and micro-composites’ mechanics parameters together.This has laid the foundation for further research into fracture properties based on micro-mechanics.The proposed tension constitution law and R-curve can be references for future UHPCC fracture evaluation.
文摘Abstract： The purpose of this paper is to evaluate the suitability of using trass as a supplementary cementing material in pervious concrete. OPC （Ordinary Portland Cement） was replaced in the concrete mix by 15%, 25% and 35% weight percentages and the results were compared with reference mixtures with 100% Portland cement. The variables in this study were trass content, aggregate size and water to cement ratio. Sixteen eases of concrete mixtures were tested to study physical and mechanical properties of hardened concrete, including porosity, permeability, compressive strength, splitting-tensile strength and flexural strength at various ages. Results indicated that mechanical properties of the pervious concrete marginally decreased with the increased content of trass when compared to the reference mixtures. However, at later ages the differences were insignificant.
