Experiments were divided into two parts; one part is to understand the basic properties of high flowable VA/VeoVa-modified cement mortar with different polymer cement ratio (P/C) and the weight ratio of fine aggregate to cement (C:F) and the other part is to investigate the effect of surface water spread on the concrete substrate on adhesion in tension. To understand the basic performance, the specimens were prepared with proportionally mixing VA/VeoVa redispersible powder, ordinary portland cement, silica sand, superplasticizer and viscosity enhancing agent. Here, P/C were 10, 20, 30, 50 and 75% and C:F were 1:1 and 1:3. As the change of P/C and C:F unit weight, flow test, crack resistance and adhesion in tension were measured. Three specimens with good adhesion properties were selected among specimens with different P/C and C:F. The effect of surface water evenly sprayed on concrete substrate on adhesive strength is investigated. The results show that surface water on concrete substrate increases the adhesion in tension of high flowable VA/VeoVa-modified cement mortar and additionally improves the flowability compared to the non-sprayed case.

본 연구에서는 고유동성의 SBR 개질 시멘트 모르타르의 기초적 성능을 바탕으로 콘크리트의 보수용 재료에 매우 중요한 요구성능인 부착강도에 대한 피착체의 표면에 존재하는 표면수량의 영향을 검토하는 연구가 수행하였다. 고유동성 SBR 개질 시멘트 모르타르의 기초적인 성능을 토대로 부착강도, 잔갈림성, 재료분리 저항성이 좋은 시험체를 선택하였다. 시험체는 C:F=1:1인 경우 P/C=20%, 30%의 시험체 2개, C:F=1:3인 경우 P/C=50%의 시험체 1개, 총 3개가 선택되었으며 이 3개의 배합에 대하여 피착체의 표면수량에 따른 고유동성 SBR 개질 시멘트 모르타르의 특성을 파악하였다. 표면수는 콘크리트 피착면의 단위 면적 (cm2) 당 각각 0, 0.006, 0.012, 0.017, 0.024 g이 균등하게 살포되었으며, 이에 따른 연도변화, 플로우값, 부착강도, 부착파괴형상, 내균열성 및 재료분리여부를 파악하였다. 본 연구를 통해 콘크리트 피착체에 살포된 표면수는 고유동성 SBR 개질 시멘트 모르타르의 부착강도를 증진하는 효과가 있다는 결론을 얻었다.

This study investigated the effect of surface water on concrete substrate on adhesive strength in tension of very high flowable SBR-modified cement mortar. Polymer cement ratio(P/C) were 10, 20, 30, 50 and 75% and the weight ratio of fine aggregate to cement were 1:1 and 1:3. The specimens obtained with different P/C and C:F were characterized by unit weight, flow test, crack resistance and adhesion test. Three selected specimens among these tested specimens were studied about the effect of surface water evenly sprayed on concrete substrate on adhesive strength.