This paper elaborates the relation of roughness parameters and tension softening diagram of concrete-to-concrete interface. Specimens with eight types of placing joints and three types of monolithic ones were employed for the evaluation of tension softening diagram (TSD) followed by…
This paper elaborates the relation of roughness parameters and tension softening diagram of concrete-to-concrete interface. Specimens with eight types of placing joints and three types of monolithic ones were employed for the evaluation of tension softening diagram (TSD) followed by surface observations of the ligament after fracture test. Roughness parameters were measured, which include the maximum height on the fractured surfaces (Pt), with 3-dimensional roughness analyzer. The authors calculated the key factor Φ which is the ratio of fractured part excluding detached part on the surface divided by the total ligament area. The authors assumed one of the roughness parameters as a representative height of dowel, and proposed a pull-out dowel model. The dowel model can describe some important aspects which appeared in TSDs of specimens with placing joint. 1 INTORODUCTION of the summit and the extension area of the foot of the mountain. As is known there are some types of 1.1 Concrete-to-concrete interfacial surfaces surface roughness parameters measurable with auto- Every concrete structure has inevitably concrete-to- mated equipment other than the maximum height JIS B 0601 2001). Relationship between these rough- concrete interfacial surfaces such as placing joint ( and casting of additional concrete for repair and re- ness parameters and mechanical performance of the inforcement. In these days of heading towards ra- interface is not known, so far. tional structural design and economical construction, there are lasting needs for making the enhancement 1.3 Purpose of the research of the adhesion performance possible through com- This paper focuses on integrating the knowledge of plete understanding of the adhesion mechanisms, surface roughness of concrete-to-concrete interfacial which is the main topic of this paper.