Wang Yupu, Li Jiazheng, Shi Yan
Institute of Materials and Structure, Changjiang River Scientific Research Institute, Wuhan 430010, China.
Research Center of Water Engineering Safety and Disaster Prevention of Ministry of Water Resources, Wuhan 430010, China.
Materials (Basel). 2023 Oct 14;16(20):6693. doi: 10.3390/ma16206693.
The layer bonding performance of hydraulic engineered cementitious composites (HECCs) plays an important role in their application in hydraulic buildings. This performance encompasses the bonding between layers of HECCs, as well as between HECCs and normal mortar (NM) layers. The influence of various factors on the layer bonding performance of HECCs was investigated. These factors included different pouring intervals (0 min, 20 min, 40 min, 60 min, 2.5 h, 7 days, 14 days, and 28 days), pouring directions (horizontal and vertical), degree of saturation (100%, 70%, 50%, 30%, and 0%), and surface roughness (varying sand-pour roughness). It was found that longer pouring interval times led to a decrease in the layer bonding performance, and the strength of the layer bonding fell below 50% compared to concrete without layers, with the lowest recorded strength being only 1.12 MPa. The layer's horizontal flexural strength surpassed the vertical flexural strength, but the horizontal compressive strength fell below the vertical compressive strength. Additionally, the bonding performance of the substrate at 0% saturation was 15-20% lower compared to other saturation levels. Notably, roughness significantly enhanced the performance of HECC layers, with improvements reaching a maximum of 180-200%. Furthermore, the layer performance of HECCs and NM experienced an improvement of 20.5-37.5%.
水工工程水泥基复合材料（HECCs）的层间粘结性能在其水工建筑物应用中起着重要作用。该性能包括HECCs各层之间以及HECCs与普通砂浆（NM）层之间的粘结。研究了各种因素对HECCs层间粘结性能的影响。这些因素包括不同的浇筑间隔时间（0分钟、20分钟、40分钟、60分钟、2.5小时、7天、14天和28天）、浇筑方向（水平和垂直）、饱和度（100%、70%、50%、30%和0%）以及表面粗糙度（不同的撒砂粗糙度）。研究发现，较长的浇筑间隔时间会导致层间粘结性能下降，与无层混凝土相比，层间粘结强度下降至50%以下，记录到的最低强度仅为1.12MPa。该层的水平抗弯强度超过垂直抗弯强度，但水平抗压强度低于垂直抗压强度。此外，饱和度为0%时基材的粘结性能比其他饱和度水平低15 - 20%。值得注意的是，粗糙度显著提高了HECC层的性能，提高幅度最大可达180 - 200%。此外，HECCs与NM的层性能提高了20.5 - 37.5%。
