高稳定发泡剂与泡沫混凝土的优化设计及性能研究
发布时间：2018-08-27 07:31
【摘要】：随着我国道路交通量和交通荷载的日益增加，部分早期高速公路和城市道路的改扩建工程不断增，建设中所存在的占地拆迁、软土地基处理、冻土破坏以及管涵外保温施工等问题对道路基层和面层的质量和耐久性有着重要的影响，不少关键技术没有得到有效解决。泡沫混凝土作为一种自立性好、保温抗冻、来源广泛且价格低廉的新型道路基层材料，近些年在道路建设中取得了一定的应用和发展，但也出现了诸如泡沫不稳定、强度较低、吸水率过大等问题。本文参照《公路路面基层施工技术规范》（JTJ034-2000）中对基层材料强度的要求，进行高稳定发泡剂和泡沫混凝土的制备与配比优化设计，系统地探讨了影响发泡剂、泡沫混凝土及其内部孔结构的因素、改善措施和机理。主要内容包括： （1）通过对比研究不同阴离子表面活性剂的泡沫性能，以及不同稳泡剂掺量对发泡倍数和泡沫稳定性的影响，制备出两种性能优越的泡沫混凝土发泡剂，即GL-1和GL-2型。研究表明：GL-1型发泡剂制备的泡沫在空气中表现出较高的稳定性，但性能受外界温度变化的影响较大。GL-2型发泡剂在温度5~45℃的条件下，仍然保持其较高的稳定性，对道路施工条件的适应性较强，且泡沫细腻均匀，有光泽，发泡倍数为42.2倍，，1h泌水量和沉降距分别为16.3ml和1.3mm； （2）以抗压强度、吸水率、导热系数和干缩值为性能指标，系统研究不同水灰比、粉煤灰、砂和纤维掺量对不同干密度等级下的泡沫混凝土性能的影响。研究表明：在水胶比为0.44，粉煤灰替代水泥用量30%时，制备的600级泡沫混凝土性能最优，28d抗压强度为4.14MPa。水料比为0.42，胶砂比为1:1.8，减水剂掺量为1.2%时，制备的1000级泡沫混凝土28d抗压强度达到最高为4.54MPa，其中砂掺量对强度的影响最大。水料比0.58，纤维掺量0.10%时制备的400级泡沫混凝土，7d和28d抗压强度分别为0.76MPa和1.32MPa，吸水率为17.5%，导热系数为0.072W/(m·K)，干缩为0.98mm/m，制备的不同干密度下的泡沫混凝土强度指标可满足不同等级公路对基层和底基层的要求。 （3）利用显微镜对不同干密度、水灰比以及胶砂比下的泡沫混凝土内部气孔结构进行观察，推导并计算出不同干密度和水灰比下的泡沫混凝土孔隙率，并利用Image J图像分析软件对其平均孔径进行测量，研究表明：随着干密度等级的增大，气孔直径和孔隙率逐渐减小，砂掺量越大，对孔结构的破坏越明显。 （4）结合泡沫混凝土28d抗压强度、孔隙率和孔径的数据，以Griffith断裂力学和复合材料理论为基础，对泡沫混凝土强度和孔结构之间的关系进行定量分析与修正，并建立相应的数学模型，揭示泡沫混凝土强度与其孔隙率和孔径大小之间的关系。
[Abstract]:With the increasing traffic volume and traffic load in our country, the reconstruction and extension projects of some early freeways and urban roads have been increasing, the construction of the existing land removal, soft soil foundation treatment, The damage of frozen soil and the construction of pipe and culvert external insulation have important influence on the quality and durability of road base and surface layer, and many key technologies have not been solved effectively. As a new type of road base material with good independence, good insulation and cold resistance, wide sources and low price, foam concrete has been applied and developed in road construction in recent years, but it has also appeared such as foam instability and low strength. Excessive water absorption and other problems. In this paper, according to the requirement of material strength in JTJ034-2000, the preparation and proportion optimization design of high stability foaming agent and foamed concrete are carried out, and the influence of foaming agent on foaming agent is discussed systematically. Foam concrete and its internal pore structure factors, improvement measures and mechanisms. The main contents are as follows: (1) the foam properties of different anionic surfactants and the effects of different amount of foam stabilizers on foaming ratio and foam stability are studied. Two foaming agents of foamed concrete, GL-1 and GL-2, were prepared. The results showed that the foams prepared with the foaming agent of 1: GL-1 exhibited high stability in air, but the properties of the foaming agent were greatly influenced by the outside temperature. GL-2 type foaming agent maintained its high stability at the temperature of 545 鈩
本文编号：2206558
[Abstract]:With the increasing traffic volume and traffic load in our country, the reconstruction and extension projects of some early freeways and urban roads have been increasing, the construction of the existing land removal, soft soil foundation treatment, The damage of frozen soil and the construction of pipe and culvert external insulation have important influence on the quality and durability of road base and surface layer, and many key technologies have not been solved effectively. As a new type of road base material with good independence, good insulation and cold resistance, wide sources and low price, foam concrete has been applied and developed in road construction in recent years, but it has also appeared such as foam instability and low strength. Excessive water absorption and other problems. In this paper, according to the requirement of material strength in JTJ034-2000, the preparation and proportion optimization design of high stability foaming agent and foamed concrete are carried out, and the influence of foaming agent on foaming agent is discussed systematically. Foam concrete and its internal pore structure factors, improvement measures and mechanisms. The main contents are as follows: (1) the foam properties of different anionic surfactants and the effects of different amount of foam stabilizers on foaming ratio and foam stability are studied. Two foaming agents of foamed concrete, GL-1 and GL-2, were prepared. The results showed that the foams prepared with the foaming agent of 1: GL-1 exhibited high stability in air, but the properties of the foaming agent were greatly influenced by the outside temperature. GL-2 type foaming agent maintained its high stability at the temperature of 545 鈩
本文编号：2206558
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