摘要
混凝土强度等级越高,脆性越大,此类问题在轻骨料混凝土中更为突出。采用钢纤维、碳纤维、聚丙烯纤维等对其进行增韧,虽能取得一定效果,但对工程造价和环境的影响较显著。基于植物纤维具有来源广泛、环境友好等特点,以粉煤灰陶粒混凝土为例,探寻了稻草纤维掺量、形状、长度和粉煤灰掺量对其力学性能的影响;基于界面过渡区理论,从轻骨料混凝土拉压比、抗冲击强度角度分析了稻草纤维的增韧效果。结果表明:拉压比随纤维掺量的增加而增加,随纤维长度、粉煤灰掺量的增加而减小;纤维改性后拉压比虽出现了降低,但仍高于无纤维组;稻草纤维提高拉压比的效果与其他纤维相近,且改性后提高抗冲击强度效果显著。基于回归分析,提出了混凝土劈裂抗拉强度预测模型,验证结果表明:该模型预测值与文献试验值相对误差在7%以内;混凝土强度等级越高,预测结果越准确,该模型可用于纤维轻骨料混凝土、高性能混凝土劈裂抗拉强度的预测。
The higher the concrete strength grade,the greater the brittleness,and such problems are more prominent in lightweight aggregate concrete.Using steel fiber,carbon fiber,polypropylene fiber,etc.to increase the toughness of concrete,although it can achieve certain effects,but has a significant impact on project cost and environment.Based on the wide range of plant fiber sources and environmental friendliness,taking fly ash ceramsite concrete as an example,the influence of straw fiber amount,shape,length and amount of fly ash on the mechanical properties of fly ash ceramsite concrete was explored.Based on the interface transition zone theory,the effect of straw fiber on enhancing toughness was analyzed from the perspective of concrete tensile and compression ratio and impact strength.The results showed that the tensile-compression ratio increases with the increase of straw fiber content,and decreases with the increase of fiber length and fly ash content,the tensile-compression ratio decreases after the fiber modification,but higher than the fiber-free group,the effect of straw fiber on increasing the tensile-compression ratio is similar to that of other fibers,and the effect of improving the impact strength of concrete after modification is remarkable.Based on regression analysis,a prediction model for splitting tensile strength of fiber lightweight aggregate concrete was proposed.The verification results showed that the relative error between the predicted value of the model and the experimental value of the literature was within 7%,the higher the concrete strength level,the more accurate the prediction result,it can be used to predict the tensile strength of fiber concrete and high performance concrete.
作者
张学元
吕春
张道明
王丽
李扬
ZHANG Xueyuan;LYU Chun;ZHANG Daoming;WANG Li;LI Yang(School of Architecture and Civil Engineering,Qiqihar University,Qiqihar 161006,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第2期2034-2038,共5页
Materials Reports
基金
黑龙江省教育厅基本业务专项面上项目(135209232)
齐齐哈尔大学科研资助项目(135309357)
黑龙江省教育厅基本业务专项青年项目(135209310)~~
关键词
稻草纤维
粉煤灰陶粒
减脆增韧
界面过渡区
拉压比
劈裂抗拉强度
straw fiber
fly ash ceramsite
embrittlement reduction and increase toughness
interface transition zone
tension and compression ratio
splitting tensile strength
