陶粒体积分数对陶粒混凝土破坏行为的影响

发布时间：2018-03-08 23:12

本文选题：陶粒混凝土　切入点：体积分数　出处：《宁波大学》2013年硕士论文　论文类型：学位论文

【摘要】：本文利用WAW-2000型微机控制电液伺服万能机和分离式霍普金森压杆（SHPB）分别对砂浆混凝土、C40混凝土和不同体积分数的陶粒混凝土进行静态压缩实验和冲击压缩实验，来研究陶粒骨料体积分数对陶粒混凝土破坏行为的影响。静态实验结果表明陶粒混凝土的静态抗压强度随着陶粒体积百分比的增加而减小，但当陶粒体积分数大于30%时，抗压强度的减小程度明显变小。与普通混凝土和砂浆混凝土不同，陶粒混凝土试样的尺寸效应并不明显。当陶粒混凝土试样的尺寸从150mm×150mm×150mm变为Φ70mm×35mm，陶粒混凝土的抗压强度几乎不变。动态SHPB实验的结果表明，陶粒混凝土力学性能的应变率敏感性与陶粒的体积分数有关，体积分数越小的陶粒混凝土对应变率越敏感；陶粒混凝土的动态抗压强度小于砂浆混凝土和C40混凝土，，且随着陶粒体积分数的增大而减小；但最大应变则明显要大于普通混凝土与砂浆混凝土。打击气压分别为0.2MPa、0.4MPa、0.6MPa和0.8MPa的冲击动态压缩实验表明，普通混凝土试样和砂浆混凝土试样吸收的能量与入射能呈明显的线性关系，而陶粒混凝土随着陶粒体积百分比的增加，即从15%增加到48%，陶粒混凝土所吸收的能量随入射能的增加而增加，但趋势逐渐变小。使用改进的RHT模型对实验结果进行了数值拟合。引进当前面所对应的归一化静水压参量和应变增量，改进了损伤量D的描述，从而改进了在混凝土数值计算中广泛应用的RHT模型。改进RHT模型得到的理论应力应变曲线与普通混凝土的实验曲线吻合良好，但使用该模型对陶粒混凝土进行数值拟合得到的参数波动较大，表明该模型在未考虑陶粒体积分数的前提下并不适用于陶粒混凝土。
[Abstract]:In this paper, WAW-2000 microcomputer controlled electro-hydraulic servo universal machine and split Hopkinson compression bar SHPBwere used to carry out static compression tests and impact compression tests on mortar concrete concrete C40 concrete and ceramsite concrete with different volume fraction, respectively. To study the effect of the volume fraction of ceramsite aggregate on the failure behavior of ceramsite concrete. The static experimental results show that the static compressive strength of ceramsite concrete decreases with the increase of the volume percentage of ceramsite, but when the volume fraction of ceramsite is greater than 30%, Different from ordinary concrete and mortar concrete, the size effect of ceramsite concrete specimen is not obvious. When the size of ceramsite concrete sample changes from 150 mm 脳 150 mm 脳 150 mm to 桅 70 mm 脳 35 mm, the compressive strength of ceramsite concrete is almost unchanged. The results of dynamic SHPB experiment show that the strain rate sensitivity of the mechanical properties of ceramsite concrete is related to the volume fraction of ceramsite, and the smaller the volume fraction is, the more sensitive the strain rate is to the strain rate of ceramsite concrete. The dynamic compressive strength of ceramsite concrete is smaller than that of mortar concrete and C40 concrete, and decreases with the increase of volume fraction of ceramsite, but the maximum strain is obviously greater than that of ordinary concrete and mortar concrete. The impact dynamic compression experiments with the impact pressure of 0.2 MPA and 0.8 MPA show that the energy absorbed by ordinary concrete samples and mortar concrete samples is linearly related to the incident energy, while the percentage of ceramsite concrete increases with the increase of the volume percentage of ceramsite, and the impact compression test shows that the energy absorbed by ordinary concrete samples and mortar concrete samples is linearly related to the incident energy. That is, from 15% to 48, the energy absorbed by ceramsite concrete increases with the increase of incident energy, but the trend becomes smaller. The modified RHT model is used to simulate the experimental results. The normalized hydrostatic pressure parameters and strain increments corresponding to the above model are introduced to improve the description of the damage quantity D. Thus, the RHT model, which is widely used in concrete numerical calculation, is improved. The theoretical stress-strain curve obtained by the improved RHT model is in good agreement with the experimental curve of ordinary concrete. However, the parameters obtained by numerical fitting of ceramsite concrete with this model fluctuate greatly, which indicates that the model is not suitable for ceramsite concrete without considering the volume fraction of ceramsite.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528

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