泡沫混凝土稳定性研究

发布时间：2018-04-08 12:35

本文选题：泡沫混凝土　切入点：稳定性　出处：《合肥工业大学》2017年硕士论文

【摘要】：近年来,泡沫混凝土得到了越来越广泛的应用。但实际运用中常出现塌陷、沉降大等浆体不稳定现象;此外,对泡沫混凝土稳定性的认识也不尽一致。本文的目的是探讨泡沫混凝土稳定的概念和表示方法,分析影响稳定性的主要因素,配制出稳定性良好的泡沫混凝土。本文首先从泡沫混凝土硬化成型的角度明确了泡沫混凝土稳定性的概念,认为稳定性即泡沫混凝土硬化后在竖向保持具有细小、均匀、封闭的孔结构且浇筑表面无沉降或沉降较小状态的性质。新拌混凝土的状态和硬化泡沫混凝土的结构可以反映稳定性的大小,提出了定量表示泡沫混凝土稳定性的指标体系,即泡沫混凝土的沉降率、动态体积吸水率比、平均孔径比、圆度值分布等。在上述工作的基础上,研究了发泡剂浓度、水灰比、聚羧酸减水剂、增稠剂HPMC等参数对泡沫混凝土稳定性的影响,测定相应的指标参数并分析各因素对泡沫混凝土稳定性的规律。结果表明,所提出的指标泡沫混凝土的沉降率、动态体积吸水率比、平均孔径比等用于表示稳定性是合适的;同时,得到了这些因素对稳定性影响的规律性,即随着发泡剂稀释浓度的增加,水灰比的增大,减水剂掺量和HPMC掺量的提高,泡沫混凝土稳定性均呈现先提高后降低的作用,这些因素对泡沫混凝土的稳定性均具有一个最佳值。按照本文确定的各因素最佳值,即发泡剂稀释30倍,水灰比0.45,聚羧酸减水剂和HPMC掺量为水泥质量的0.03%配制成干密度等级为500kg/m3的泡沫混凝土,物理力学性能优良,其流动度为180mm,干密度为514 kg/m3,28天抗压强度为2.3MPa,导热系数为0.118W/(m.K)。该混凝土的沉降率为1.5%,平均孔径比为1.02且上部平均孔径为150μm,具有良好的稳定性。
[Abstract]:In recent years, foam concrete has been more and more widely used.However, collapse and large settlement are often found in practical application, and the understanding of the stability of foamed concrete is not consistent.The purpose of this paper is to discuss the concept and expression method of foam concrete stability, to analyze the main factors affecting the stability, and to prepare the foam concrete with good stability.In this paper, the concept of stability of foamed concrete is defined from the point of view of hardening and forming of foamed concrete. It is considered that the stability of foamed concrete is fine and uniform in the vertical direction after hardening.The property of a closed hole structure with no settlement or smaller settlement on the cast surface.The state of fresh concrete and the structure of hardened foam concrete can reflect the magnitude of stability. A quantitative index system for the stability of foam concrete is put forward, that is, the settlement rate of foam concrete, the dynamic volume water absorption ratio, and the average pore size ratio.Roundness distribution, etc.Based on the above work, the effects of foaming agent concentration, water-cement ratio, polycarboxylic acid water reducer and thickener HPMC on the stability of foamed concrete are studied.The corresponding index parameters were measured and the law of the stability of foamed concrete was analyzed.The results show that the proposed index, such as settlement rate, dynamic volumetric water absorption ratio and average pore diameter ratio, are suitable to express stability, and the regularity of the influence of these factors on stability is obtained.That is, with the increase of dilute concentration of foaming agent, the increase of water-cement ratio, the increase of water reducer and HPMC content, the stability of foamed concrete increases first and then decreases.These factors have an optimum value for the stability of foamed concrete.According to the optimum value of various factors determined in this paper, foaming agent diluted 30 times, water-cement ratio 0.45, polycarboxylic acid water-reducing agent and HPMC content 0.03% of cement mass, foamed concrete with dry density grade 500kg/m3 has good physical and mechanical properties.The flowability is 180 mm, the dry density is 514 kg / m ~ (3) and the compressive strength is 2.3 MPA for 28 days, and the thermal conductivity is 0.118 W / m ~ (3) 路K ~ (-1) 路m ~ (-1) 路m ~ (-1) 路m ~ (-1).The settlement rate of the concrete is 1.5, the average pore diameter ratio is 1.02 and the upper average pore diameter is 150 渭 m. The concrete has good stability.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528.2

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