寒区低熟料HPC路面塑性收缩影响因素研究

发布时间：2018-01-10 04:10

本文关键词：寒区低熟料HPC路面塑性收缩影响因素研究　出处：《东北林业大学》2015年硕士论文　论文类型：学位论文

【摘要】：HPC(高性能混凝土)作为一种以耐久性为设计指标的新型混凝土,在实际工程应用中占比越来越大。在混凝土的发展进程中,开裂成为其不可避免的问题之一,其中混凝土早期塑性收缩阶段产生的收缩开裂更是HPC缺陷问题中的重中之重。故本文对低熟料HPC的塑性开裂影响因素分析意义重大。本文从配合比和外界条件两方面对低熟料HPC塑性收缩进行了研究。以平板法试验为主,圆环法试验为辅,进行综合分析,并提出最优配合比。研究了不同因素对低熟料HPC28d抗折强度和湿密度的影响。复掺矿物掺合料时,粉煤灰对抗折强度和湿密度有消极作用；矿粉和硅粉对抗折强度和湿密度有积极作用；水胶比不断增大,抗折强度和湿密度逐渐减小；掺入纤维后,抗折强度和湿密度提高。通过研究分析低熟料HPC塑性收缩的内部因素,得出不同种类矿物掺合料对低熟料HPC塑性收缩影响不同。随粉煤灰掺量的不断增加,混凝土的开裂面积逐渐减少；矿粉复掺情况下随其掺量的增加混凝土的塑性收缩增大；随硅粉掺量的增加混凝土塑性收缩显著增加,其抗裂性能由大到小为：粉煤灰矿粉硅粉；水胶比对低熟料HPC塑性收缩影响复杂,其影响效果取决于与减水剂的匹配性；掺入纤维、橡胶粉的低熟料HPC可以有效抑制其塑性收缩；在同等坍落度情况下种类1减水剂抗裂性能弱于种类2和种类3,但考虑到实际应用价值可以低掺量使用；随砂率、水泥用量的增加,混凝土塑性收缩增大。同时研究分析了低熟料HPC塑性收缩的外部影响因素,风速、温度越大,混凝土塑性收缩越大；湿度越大,混凝土塑性开裂面积越小；在混凝土养护中,低风速高湿度较低温度条件为佳。圆环法试验结果验证了平板法试验分析结论,更进一步证明了水胶比与矿物掺合料是影响低熟料HPC塑性收缩的重要因素。
[Abstract]:As a new type of concrete with durability as its design index, HPC (High performance concrete) accounts for more and more in practical engineering applications. Cracking has become one of the inevitable problems. The shrinkage cracking caused by early plastic shrinkage of concrete is the most important part of HPC defect problem. Therefore, this paper is of great significance to the analysis of the factors affecting plastic cracking of low clinker HPC. The plastic shrinkage of low clinker HPC was studied in two aspects of boundary conditions. The ring test was used to analyze comprehensively and put forward the optimum mix ratio. The influence of different factors on the HPC28d flexural strength and wet density of low clinker was studied. When the mineral admixture was mixed with mineral admixture the effect of different factors on the flexural strength and wet density of low clinker was studied. Fly ash has negative effects on flexural strength and wet density. The resistance of mineral powder and silicon powder to flexural strength and wet density is positive. With the increase of water-binder ratio, the flexural strength and wet density decrease gradually. The flexural strength and wet density of low clinker HPC were increased with the addition of fiber. The internal factors of plastic shrinkage of low clinker HPC were analyzed. It is concluded that different mineral admixtures have different effects on the plastic shrinkage of low clinker HPC. With the increasing of fly ash content, the cracking area of concrete decreases gradually. The plastic shrinkage of concrete increases with the increase of mineral powder content. With the increase of the content of silica fume, the plastic shrinkage of concrete increases significantly, and the crack resistance of concrete increases from big to small: fly ash, mineral powder, silicon powder; The effect of water / binder ratio on plastic shrinkage of low clinker HPC is complex, and its effect depends on the compatibility with water reducer. The low clinker HPC with fiber and rubber powder can effectively inhibit its plastic shrinkage. Under the same slump condition, the crack resistance of type 1 water reducer is weaker than that of category 2 and category 3, but considering the practical application value, it can be used in low dosage. With the increase of sand ratio and cement content, the plastic shrinkage of concrete increases. At the same time, the external factors of plastic shrinkage of low clinker HPC are analyzed. The higher the wind speed and temperature, the greater the plastic shrinkage of concrete. The larger the humidity, the smaller the plastic cracking area of concrete; In the concrete maintenance, low wind speed and high humidity is better than the low temperature condition. The circle method test results verify the conclusion of plate test analysis. It is further proved that the ratio of water to binder and mineral admixture is an important factor affecting the plastic shrinkage of low clinker HPC.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.2

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