Development of Cementitious Materials Utilizing Alkali-activated Yellow River Silt

The possibility of preparing cementitious materials by the alkali-activated method using Yellow River sediment(The second largest river in China)as raw material and the modification effect on different slag addition were investigated.Sodium silicate and calcium hydroxide were used as the activator,and the specimens were prepared by the press molding method.The hydration process,hydration products,pore characteristics,and mechanical properties were investigated using SEM/EDS,FTIR,TG/DTG,XRD,MIP,and uniaxial compressive strength experiments,respectively.The results showed that the compressive strength of the modified yellow river silt-based cementitious material was significantly increased when the water glass dosage was 12 wt%(Ms=1.8)and the slag dosage was 40%,and its 90-day maximum compressive strength could reach 53 MPa.

黄河动床实体模型数控加工技术试验研究

黄河动床实体模型是用于研究黄河流域演变规律及治理开发中关键技术问题和各种治理方案的模型体系,模型的准确性与上述问题的研究精度密切相关。使用分块离散成型的原理,提出了使用数控设备进行模型的分块加工,然后拼装的加工方案,并进行了相关的实验。研究表明,模型误差主要包括单块切削误差和拼接误差两部分。本试验条件下单块切削误差为:0.028 mm;6块拼接误差≤4 mm,使用重复定位校核的方法可将累积误差控制在规定范围内。

高精度钢筋混凝土管片制造技术

中铁隧道集团和葛洲坝集团联合体在南水北调中线一期穿黄工程盾构隧道的施工中通过采用综合振捣和蒸汽养护工艺，顺利完成管片生产任务；在施工过程中解决了干硬性混凝土在精密模具中的局部离析、管片侧面凹凸槽内容易出现气泡、高强度混凝土崩角、掉块；混凝土成品精度高、高强度混凝土修补等一系列难题。