【摘要】：混凝土作為土木工程材料被廣泛的應(yīng)用在國民經(jīng)濟(jì)建設(shè)之中。混凝土有著來源豐富、經(jīng)濟(jì)性好、可塑性強(qiáng)等優(yōu)點(diǎn)。然而自重較大、抗拉性能差等缺點(diǎn)一直限制著混凝土的發(fā)展。為了改善這些缺點(diǎn),人們長久以來不斷尋找將新的材料加入到混凝土中。大量研究表明,在以天然浮石作為混凝土粗骨料的輕骨料混凝土中摻入纖維不但可以增強(qiáng)混凝土的韌性,而且可以改善其耐久性能并且減輕混凝土的自重。本論文將結(jié)合內(nèi)蒙古自治區(qū)豐富的天然浮石儲(chǔ)備這一地區(qū)資源優(yōu)勢(shì),使用內(nèi)蒙古自治區(qū)烏蘭察布市集寧地區(qū)的天然浮石作為輕骨料的混雜纖維輕骨料混凝土,著重研究混雜纖維(聚丙烯纖維和玄武巖纖維)的摻入對(duì)于輕骨料浮石混凝土的宏觀性能和微觀性能間的關(guān)系。在宏觀方面,本文通過混凝土抗壓強(qiáng)度試驗(yàn)來研究混雜纖維輕骨料混凝土。而凍融循環(huán)破壞試驗(yàn),對(duì)于質(zhì)量損失率和相對(duì)動(dòng)彈性模量這兩個(gè)參數(shù)作了具體的分析。并且探討纖維對(duì)于混凝土宏觀性能方面增強(qiáng)的機(jī)理在微觀方面,本論文在不同尺度利用不同方式,觀測(cè)并且計(jì)算了混凝土的孔結(jié)構(gòu)參數(shù)。并且討論了不同的分形維數(shù)的計(jì)算對(duì)于模型的影響,最終選擇了兩種方法對(duì)于兩個(gè)尺度分別計(jì)算出分形維數(shù)。并利用該分形維數(shù)與之前的試驗(yàn)參數(shù)和結(jié)果做了進(jìn)一步的討論和研究。最終利用將分形維數(shù)與凍融損傷模型相結(jié)合,得到了基于分形維數(shù)的混雜纖維輕骨料混凝土的凍融損傷模型。研究結(jié)果表明:在混雜纖維輕骨料混凝土中,當(dāng)玄武巖纖維和聚丙烯纖維的摻量在一個(gè)合理的范圍之內(nèi)時(shí),混雜纖維輕骨料混凝土的力學(xué)性能和抗凍耐久性能將會(huì)有一定的提升。且聚丙烯-玄武巖纖維的最佳摻量為:聚丙烯纖維0.6κg/m3,玄武巖纖維0.7kg/m3。
[Abstract]:Concrete, as a civil engineering material, is widely used in national economic construction. Concrete has many advantages, such as rich source, good economy, strong plasticity and so on. However, the development of concrete has been limited by the shortcomings of large self-weight and poor tensile performance. In order to improve these shortcomings, people have been looking for new materials to add to concrete for a long time. A large number of studies have shown that the addition of fiber into lightweight aggregate concrete with natural pumice as coarse aggregate can not only enhance the toughness of concrete, but also improve its durability and reduce the weight of concrete. In this paper, combined with the rich natural pumice reserve in Inner Mongolia Autonomous region, the mixed fiber lightweight aggregate concrete is used as lightweight aggregate, which is based on the natural pumice in Jining area of Wulanchabu City, Inner Mongolia Autonomous region. The relationship between the macroscopic and microscopic properties of lightweight aggregate pumice concrete with the addition of hybrid fiber (polypropylene fiber and basalt fiber) is studied in detail. In macroscopical aspect, this paper studies hybrid fiber lightweight aggregate concrete through concrete compressive strength test. In the freeze-thaw cycle failure test, the two parameters of mass loss rate and relative dynamic elastic modulus are analyzed in detail. The mechanism of strengthening the macro performance of concrete by fiber is discussed in the microscopic aspect. In this paper, the pore structure parameters of concrete are observed and calculated by using different methods at different scales. The influence of different fractal dimensions on the model is discussed. Finally, two methods are selected to calculate the fractal dimensions for the two scales. The fractal dimension is further discussed and studied with the previous experimental parameters and results. Finally, the freeze-thaw damage model of hybrid fiber lightweight aggregate concrete based on fractal dimension is obtained by combining fractal dimension with freeze-thaw damage model. The results show that in hybrid fiber lightweight aggregate concrete, when the content of basalt fiber and polypropylene fiber is within a reasonable range, The mechanical properties and frost durability of hybrid fiber lightweight aggregate concrete will be improved to a certain extent. The optimum content of polypropylene-basalt fiber is as follows: polypropylene fiber 0.6 kg 鈮，

本文編號(hào)：2476487