粉煤灰改性固体废弃物胶固粉的制备及性能研究

以电石渣和粉煤灰这两类固体废弃物为主要原料,制备了不同粉煤灰掺量的固体废弃物胶固粉。研究了粉煤灰掺杂比例对胶固粉水化进程、微观形貌、破坏形态和力学性能等方面的影响。结果表明,掺入适量粉煤灰后加速消耗了水泥熟料,提高了胶固粉的水化反应速率,在28 d龄期下,当粉煤灰的掺量为30%(质量分数)时,胶固粉中孔隙数量最少,结构密实度最高。胶固粉在受力过程中破坏形态相似,裂纹自上而下均为条形裂纹,且上部出现了坍塌现象。随着粉煤灰掺量的增大,胶固粉的凝结时间逐渐增大,流动度和化学结合水量持续降低,抗压强度和最大应力先增大后降低变化。在28 d龄期下,当粉煤灰的掺量为30%(质量分数)时,胶固粉的抗压强度最大为14.85 MPa,在相同应变下的应力最高为15.70 MPa。分析可知,粉煤灰的最佳掺量为30%(质量分数)。

碱激发剂对粉煤灰地聚物混凝土的性能影响

以偏高岭土、一级粉煤灰和矿渣为原料,选择LiOH为碱激发剂,制备了不同LiOH掺杂量(1%,3%,5%,7%(质量分数))的粉煤灰地聚物混凝土。研究了LiOH掺杂量对粉煤灰地聚物混凝土力学性能和抗冻性能的影响。结果表明,掺入碱激发剂LiOH促进了地聚物混凝土中活性硅和活性铝发生反应,生成的凝胶数量增多,提高了混凝土的致密度;当LiOH的掺杂量为5%时,混凝土的抗压强度和抗折强度达到了最大值,分别为48.91和5.56 MPa;适量LiOH的添加提高了混凝土的热稳定性和抗冻性能,在950℃,当LiOH的掺杂量为5%时,混凝土的失重最低仅为3.9%;冻融循环100次时,LiOH的掺杂量为5%的混凝土的质量损失率最低为0.93%,相对动弹性模量最大为88.24%,抗冻性能最佳。综合分析可知,LiOH的最佳掺杂量为5%。

“一带一路”背景下提升西部民族地区高校中外合作办学质量路径研究--以呼伦贝尔学院为例

在“一带一路”背景下、西部民族地区中外合作办学项目存在教学资源引进相对不足,中外双方共同开发课程少,外部质量保障力度不足、双方合作的深度和广度不够等问题。这些问题影响中外合作办学质量的提升。通过借鉴东部地区中外合作办学成功经验,结合呼伦贝尔学院自身发展实际,在提高生源质量、引进优质教学资源、加强质量监控体系建设三个方面提出提升西部民族地区地方高校中外合作办学质量的策略,对促进中外合作办学研究的理论与实践进一步融合,提升中外合作办学质量,促进中外合作办学可持续发展意义重大。

Effects of Firing and Operating Atmospheres on Microstructure and Properties of Phosphate Bonded Cr_2O_3-Al_2O_3-ZrO_2 Bricks

The microstructure and properties of phosphate bonded Cr2O3 - -Al2O3 - ZrO2 specimens fired in air or coke bed were investigated firstly. Then property change of the Cr2 O3 - Al2 O3 - ZrO2 bricks after secondary treat- ment in simulation environment was studied. Finally, corrosion resistances of the Cr2 O3 - Al2 O3 - ZrO2 bricks in air and simulation environment were compared; and microstructure of on-site used Cr2O3 - Al2O3 - ZrO2 bricks in slagging gasifiers was analyzed. The results show that the atmosphere has significant effect on the mi- crostructure and properties of the phosphate bonded Cr2O3 -Al2O3 -ZrO2 bricks. As the specimens are fired in air, the phosphate forms a composite solid solution with Cr2 O3 and Al2 O3, therefore, strength of the speci- mens is enhanced. For specimens fired in coke bed, a certain amount of gases are generated owing to the re- duction of phosphate and part of Cr2 O3, which results in the increasing number and size of the pores, bad interfa- cial bonding between Cr2O3 aggregates and matrix as well as low strength of the specimens. During service process in reducing atmosphere, the phosphate binder and part of Cr2O3 in edge of the specimens are also re- duced, leading to significant increase of number and size of the pores in the edge of the specimens; as a result, inreducing atmosphere, the specimens show much worse corrosion resistance than in air.

呼伦贝尔地区持续高寒气候条件下HRB400级钢筋的力学性能试验研究

呼伦贝尔地处高纬度高寒地带,秋冬季节更替引起室外温度骤变。为研究持续低温后温度骤变(从-40℃骤变到20℃以上)对钢筋的影响,采用微机控制万能电子试验机对不同型号HRB400钢筋(■12、■14、■16)的冷冻后进行拉拔试验。试验结果表明:温度骤变使钢筋的屈服强度σy和抗拉强度σu均有所提高,断后伸长率δ和断面收缩率ψ均有所减小,说明温度骤变使钢筋强度一定程度的提高,使塑性一定程度的降低;温度骤变对钢筋的弹性模量E影响不明显,且应力-应变曲线的形状基本类似。

呼伦贝尔多年冻土区工程病害与冻土工程 地质特征及评价

呼伦贝尔多年冻土区不良地质现象导致的工程病害有沉陷、冻胀、冰锥、涎流冰、冰丘、热融湖等现象。沉陷是工程遭受破坏相对普遍的现象。同时,季节活动层反复冻融引起的病害亦不能忽视。多年冻土自北向南分Ⅰ、Ⅱ和Ⅲ区,冻土工程类型多样,Ⅰ和Ⅱ区高含冰量土分布更为广泛;Ⅰ区西北部有低温不稳定区,其它为高温不稳定区和极不稳定区,冻土呈逐年退化状态。冻土不良地质现象发育,工程地质条件较差、极差地段交错分布。