低胶凝材料用量自密实混凝土设计及性能研究

发布时间：2018-04-24 22:08

本文选题：低胶凝材料用量 + 自密实混凝土　；参考：《深圳大学》2017年硕士论文

【摘要】：自密实混凝土(SCC)是依靠其自重作用而无需额外人工或机械振捣,在浇筑施工中具有大流动性、匀质性和抗离析性等优异工作性能,且硬化后具备良好力学和耐久性能的高性能混凝土。然而SCC设计中通常胶凝材料含量较大,导致水化热较高、硬化后收缩、徐变较大,且生产混凝土过程产生的CO2排放量较大将加重环境污染。为了实现SCC绿色生态化,本研究基于可压缩堆积模型的颗粒堆积理论,设计出平衡工作及力学性能且符合环境效益的低胶凝材料用量绿色SCC。基于上述问题及目的,本研究具体内容包括以下几个方面:(1)基于可压缩堆积模型的颗粒堆积理论,首先对净浆、砂浆两个体系进行研究:分析了净浆、砂浆两个层级体系不同材料组成参数对堆积密实度的变化规律,同时从颗粒堆积的角度通过正交设计方法研究了不同材料组成参数对净浆、砂浆流变性能的变化趋势,并通过固体颗粒浓度理论建立了砂浆堆积密实度与流变性能的关系模型,并为设计低胶凝材料用量的绿色SCC提供理论基础。(2)在净浆、砂浆堆积密实度对其流变性能影响的研究基础上,通过正交设计方法研究了胶凝材料用量、砂率、超细砂粉与粉煤灰体积掺量等不同材料参数对混凝土堆积密实度的影响趋势,并以骨料与粉体体积比参数为桥梁,揭示了混合料堆积密实度对SCC工作性能的变化趋势。在此基础上,通过3种颗粒分布曲线模型配置的混凝土性能进行对比分析,验证了经CPM模型优化后的SCC能够取得工作性能与力学性能上的平衡,并进一步研究了粉煤灰与纳米TiO2复配的低胶凝材料用量绿色SCC性能。(3)通过堆积密实度与SCC性能的影响关系,得出了混合料堆积密实度t合理范围为0.8150~0.8350,对应的SCC满足流动性能要求,同时具备良好的间隙通过性及抗离析性能,且硬化后混凝土28天抗压强度在35MPa以上,此时胶凝材料用量最低达到340 kg/m3,在此基础上复掺5%纳米TiO2,能够配置出C40以上的低胶凝材料用量纳米SCC。(4)基于可压缩堆积模型及SCC性能研究,推荐了一种平衡工作及力学性能的低胶凝材料用量绿色SCC配合比设计方法,并对该方法的实用性和可行性进行了验证。
[Abstract]:Self compacting concrete (SCC) is a high performance concrete with excellent working properties, such as large fluidity, uniformity and resistance to segregation in pouring construction, which is dependent on its self weight effect without additional manual or mechanical vibration, and has good mechanical and durable properties after hardening. However, in the design of SCC, the content of the cementitious material is large, resulting in the hydration heat. In order to realize the green ecology of SCC, this study is based on the theory of particle accumulation in the compressible accumulation model, and designs a green SCC. based on the low cementitious material for the balance work and mechanical properties and the environmental benefits in order to realize the green ecology of the CO2. The main contents of this study include the following aspects: (1) based on the theory of granular accumulation based on compressible accumulation model, first of all, two systems of pulp and mortar are studied. The changes in the accumulation density of different material parameters of the two layers of the mortar and mortar are analyzed, and the effect of the particle accumulation is also analyzed. The orthogonal design method studied the change trend of the rheological properties of the mortar and mortar by different material composition parameters. Through the solid particle concentration theory, the relationship model of the accumulation density and the rheological properties of the mortar was established, and the theoretical basis was provided for the design of green SCC with low cementitious material content. (2) the accumulation of mortar and the rheological properties of mortar on the rheological properties of the mortar. On the basis of the study of the performance influence, the influence trend of different material parameters, such as the amount of cementitious material, the sand rate, the volume of the superfine sand powder and the volume of the fly ash, is studied on the basis of the orthogonal design method, and the variation of the bulk density of the aggregate to the performance of the SCC is revealed. On this basis, the concrete performance of 3 kinds of particle distribution curve model is compared and analyzed. It is verified that the SCC can achieve the balance between the performance and mechanical properties after the CPM model optimization, and further studies the green SCC performance of the low cementitious material used for the combination of fly ash and nano TiO2. (3) through accumulation density In relation to the influence of SCC performance, it is concluded that the reasonable range of packing density of mixture t is 0.8150~0.8350, the corresponding SCC meets the flow performance requirements, and has good clearance and anti segregation performance, and the 28 day compressive strength of concrete is above 35MPa after hardening, and the minimum amount of cementitious material reaches 340 kg/m3 at this time, on this basis. With the addition of 5% nano TiO2, the amount of low cementitious material above C40 can be configured with nano SCC. (4) based on the compressible accumulation model and the study of SCC properties. A design method of green SCC mix ratio for low cementitious materials used in equilibrium and mechanical properties is recommended, and the feasibility and feasibility of the method are verified.

【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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