以板岩陶粒为骨料的轻混凝土制备关键问题研究

发布时间：2018-02-28 19:04

本文关键词： 板岩陶粒容重等级碱集料反应快速砂浆棒法养护　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：板岩陶粒具有多孔、轻质、高强以及可有效抑制混凝土的碱集料反应等优点,以页岩陶粒为轻骨料的混凝土因具有良好的抗震、耐久、抗裂等性能,在高层建筑、大跨度桥梁、城市立交桥、地铁和隧道等工程中应用日益广泛。开展对页岩陶粒为轻骨料的混凝土研究对于建筑节能和新型绿色建筑材料的综合应用具有重要意义。本课题的研究内容是基于湖南益阳某公司开发板岩陶粒在混凝土中的应用所做的前期研究工作,研究主要集中在如下三个方面:(1)设计并制备出符合国标要求的轻质板岩陶粒混凝土通过配合比设计和实验研究,制备出了的板岩陶粒混凝土容重等级为1300-1800kg/m3,抗压强度不低于15 MPa,坍落度大于120 mm,达到了国标JGJ 51-1990的要求。各组试验中,混凝土拌和物0 min、20 min、40 min的坍落度和扩展度依次减小;砂率为43%时,混凝土7 d和28 d强度均达到最大值,分别为26.8 MPa和28.0 MPa。对于容重1800级板岩陶粒混凝土匀质性的改善而言,HPMC比CMC效果要好,当HPMC掺量为0.8%时,板岩陶粒混凝土的抗压强度为26.6 MPa,坍落度和扩展度分别为264 mm和595 mm,同时混凝土0 min、20 min和40 min的经时坍落度和扩展度降低最缓慢,有利于匀质性的改善;通过归纳分析实验数据,得到了板岩陶粒混凝土的干表观密度与抗压强度之间的关系曲线和公式y=0.0118x+1.3642,R2=0.8659。(2)测定了板岩混凝土和板岩陶粒混凝土的碱集料反应结果表明,板岩陶粒可有效抑制板岩混凝土的碱集料反应,随着板岩陶粒掺量的逐渐增加,试件14d的膨胀率逐渐减小,当掺量达到6.0%时,板岩陶粒混凝土14 d的膨胀率为0.088,膨胀抑制率51.38%;在板岩陶粒混凝土中复合加入碎石型板岩陶粒、Li OH和粉煤灰可显著地抑制碱集料反应,当掺加占总集料质量3.0%的碎石型陶粒,4.78 g Li OH,110.00 g粉煤灰,对板岩混凝土的碱集料反应有较好的抑制效果,14 d膨胀率仅为0.068%,均匀设计数据处理得到14d膨胀量和各因素关系为y=0.078+2.904×10-5X1X3-1.799×10-4X2X3。(3)通过试验比较了四种后期养护方式对对容重等级为1300kg/m3、1500kg/m3和1700kg/m3的板岩陶粒拌和物混凝土强度的影响,结果表明,得出了混凝土各龄期抗压强度增长效果较好的养护方式。脱模之后自然养护和浸水养护交替进行的方式,对于容重等级较大的板岩陶粒混凝土在3 d、7 d和28 d的抗压强度增幅最大。
[Abstract]:Slate ceramsite has the advantages of porous, light weight, high strength and can effectively suppress the alkali aggregate reaction of concrete. The concrete with shale ceramsite as light aggregate has good anti-seismic, durable, crack resistance and so on, in high-rise buildings, long span bridges, etc. Urban flyovers, The application of concrete with shale ceramsite as lightweight aggregate is becoming more and more widely used in subway and tunnel projects. It is important for building energy saving and new green building materials to study the concrete. The research content of this subject is based on. The preliminary research work done in developing the application of slate ceramsite in concrete in a company in Yiyang, Hunan Province, The research is mainly focused on the following three aspects: 1) designing and preparing lightweight slate ceramsite concrete in accordance with national standards through mix design and experimental study. The bulk density of slate ceramsite concrete is 1300-1800 kg / m ~ 3, compressive strength is no less than 15 MPA and slump is more than 120mm, which meets the national standard JGJ 51-1990. In each test, the slump and expansion of concrete mixture decrease in order of 20 minutes or 40 min. When the sand ratio is 43, the strength of concrete at 7 days and 28 days reaches the maximum values of 26.8 MPa and 28.0 MPa, respectively. For the improvement of homogeneity of bulk weight 1800 slate ceramsite concrete, the effect of HPMC is better than that of CMC, when the content of HPMC is 0.8%, The compressive strength of slate ceramsite concrete is 26.6 MPA, slump and extension are 266mm and 595mm, respectively. At the same time, the slump and expansion of slate concrete at 0 min ~ 20 min and 40 min are the slowest, which is beneficial to the improvement of homogeneity. The relationship curve and formula between dry apparent density and compressive strength of slate ceramsite concrete are obtained by induction and analysis of experimental data. The results of alkali aggregate reaction of slate concrete and slate ceramsite concrete are obtained. Slate ceramsite can effectively inhibit the alkali aggregate reaction of slate concrete. With the increasing of slate ceramsite content, the expansion rate of slate samples decreases gradually in 14 days, and when the content reaches 6.0, The expansion rate of slate ceramsite concrete is 0.088 and the inhibition rate of expansion is 51.38.The addition of Li-OH and fly ash into slate ceramsite concrete can significantly inhibit the alkali aggregate reaction. When the aggregate weight is 3.0% g, the aggregate type ceramsite is 4.78g Li OH 110.00g fly ash, The alkali aggregate reaction of slate concrete has a better inhibition effect. The expansion rate of 14 days is only 0.068, and the relation between the expansion amount of 14 days and the relationship between the factors is y 0.078 2.904 脳 10 ~ (-5) X _ 1X _ 3-1.799 脳 10 ~ (-4) X _ (2) X _ 3 ~ (3). The influence of concrete strength of slate ceramsite mixing material of 1300 kg / m 3 / m 3 and 1 700 kg / m 3 and 1 700 kg / m 3 respectively. The results show that the curing method of increasing compressive strength of each age of concrete is better, and the natural curing and soaking maintenance after demoulding are carried out alternately. For slate ceramsite concrete with larger bulk density, the compressive strength of slate concrete increased the most in 3 days, 7 days and 28 days.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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