【作者】 邓寿昌；

【导师】 罗迎社；

【作者基本信息】 中南林业科技大学 ， 林业工程， 2019， 博士

【摘要】 林区道路与桥隧等配套形成四通八达的交通网络,是山区重要的运输通道。为了满足日益增长的林区、林场的生产和生活需要,需要大量的天然砂石骨料建设适用于林区的建筑工程如林区道路、桥梁和房屋等。若就地取材进行林区开采则势必破坏当地的地质、地貌等景观,而如果能充分循环利用城、镇、乡、村拆迁后遗留的建筑固废物如废混凝土、旧钢筋等制成再生钢筋混凝土来构筑建筑物、结构物等,那将是变废为宝,保护林区生态可持续发展的建设之路。本文在广泛调研国内外再生混凝土研究现状、进展和存在不足之处的基础上,紧密结合湖南省科技厅、建设厅、广东省教育厅、长沙市科技局、株洲市建设局和惠州市城乡建设规划局科技项目开展研究,对再生混凝土配合比设计及全再生钢筋混凝土构件作深入、细致的试验研究和理论分析。力图解决全再生混凝土+全再生钢筋制作成全再生钢筋混凝土梁-柱构件存在的问题,为最大限度利用城乡旧有建筑拆迁时所造成的废混凝土和废旧钢筋的循环再生利用提供有应用价值的研究成果。本文主要做了如下3项工作:(1)废混凝土经过破碎→筛分→级配→粗细骨料,测试附加用水量,提出全再生骨料混凝土配合比设计的新方法,建立了求解再生或全再生骨料的四元或六元一次方程组及计算再生或全再生混凝土摻n种混合料的广义配合比的方程组和全再生粗-细骨料附加用水量的实用计算公式,据此配制的再生或全再生骨料混凝土的品质和强度与天然骨料混凝土大体一致,甚至还高于普通混凝土。(2)制作了24根全再生钢筋混凝土及普通钢筋混凝土梁-柱构件,其中全再生钢筋混凝土梁和普通钢筋混凝土梁-柱构件各12根,按照六种不同配比的材料组合形式分为六组,每组4根,2根为全再生钢筋梁-柱构件;2根为普通钢筋混凝土梁-柱构件,进行对比试验。添加料为聚羧酸减水剂、粉煤灰、粒化高炉矿粉,分别浇筑成型。(3)对24根全再生钢筋混凝土及普通钢筋混凝土梁-柱构件在不同加载情况下的应变、变形、裂缝、破坏特征都做了全方位的观察、测试、统计,取得了一批有价值有意义的试验数据资料。通过深入、细致的研究与分析,获得的主要成果如下:(1)按照本文提出的配合比设计新方法所配制的全再生骨料混凝土的品质是相当好的,强度甚至超过天然骨料配制的普通混凝土;(2)现场拆迁的废旧钢筋经过矫正、调直、除锈处理后进行钢筋物理力学检测,符合要求的钢筋可以用于再生混凝土构件、结构或结构体系;(3)单掺粉煤灰、复掺粉煤灰+矿粉的全再生混凝土强度明显高于同样掺粉煤灰、复掺粉煤灰+粒化高炉矿渣粉的普通混凝土,而单掺粒化高炉矿渣粉的强度则小于同样摻粒化高炉矿渣粉的普通混凝土。(4)对弯曲和弯-剪的破坏形态,全再生与普通钢筋混凝土梁相似,抗剪切箍筋应变规律沿高度先增后减,但全再生钢筋混凝土梁弯曲破坏的挠度、极限弯矩均大于普通梁弯-剪复合破坏的模式。除编号为RL-2梁,全再生钢筋混凝土梁的腹剪斜向主裂缝呈长扁核桃状,但裂缝较同一设计强度等级的普通钢筋混凝土梁稍多、稍密,宽度和挠度较大,二者之间的弯-剪裂缝的发展趋势大致相同。(5)全再生钢筋混凝土柱偏心受压实验的混凝土应变、钢筋应变、侧向位移、破坏状况与普通钢筋混凝土柱的情况相似,但承载能力>普通钢筋混凝土柱。更多还原

【Abstract】 Road in forest area is an important transport channel in mountain area,which forms a transportation network in all directions with the bridge and tunnel.In order to build the houses,the forest roads,bridges and tunnels,etc.,a large number of natural sand and gravel aggregate are needed for construction in forest areas such as roads,bridges and houses.If all of them be mined from forest area,the geological and geomorphologic landscape would be destroied.If the building waste could be full used into regeneration of reinforced concrete buildings,structures,from solid waste,such as old reinforced concrete after demolition of cities,towns or villages,it will be a ecological sustainable development path of the protection forest.Based on the survey of the status quo,progress and existing deficiencies of recycled concrete research at home and abroad,studies of tests as well as theoretical analysis in depth and in details were conducted on the fully regenerated reinforced concrete members in close collaboration with projects supported by Hunan Department of Science and Technology,Hunan Construction Department,Guangdong Education Department,Changsha Technology Bureau,Zhuzhou Construction Bureau and Huizhou Urban and Rural Construction Planning Bureau.The paper endeavors to solve problems which the mix proportion design for recycled concrete and the manufacturing fully recycled reinforced concrete beam-column with recycled concrete and recycled steel bar so as to provide valuable research findings for making a maximum use of the recycling of the wasted concrete and the wasted steel bar in the demolition of old buildings in urban and rural areas.The main works and innovating achievements in this paper as follows:The first,waste concrete was past through crushing → screening → grading made of different thickness of recycled coarse and fine aggregate,tested additional water,was put a new method of the mix proportion design forward for fully recycled aggregate concrete,the system of quaternary first order equations or six dimensional system of equations were established for the recycled or fully recycled coarse and fine aggregates,and calculating system of generalized mix ratio equation for mix n mixtures in the recycled or fully recycled concrete,additional water use of practical calculation formula,hereby the quality and strength of recycled or fully recycled aggregate concrete prepared by this new method were roughly the same as that of natural aggregate concrete,even higher than that of ordinary concrete in some fields.The second,24 fully regenerated reinforced concrete(FRRC)and ordinary reinforced concrete(ORC)beam and column members were made,including 12 fully regenerated reinforced concrete beams-columns(FRRCBs)and 12 ordinary reinforced concrete beams and columns(ORCBCs)members.According to the combination forms of 6 different proportions of materials,they were divided into 6 groups.every group of including 2 FRRCBs and 2 ORCBCs were tested and compared respectively.The additives are polycarboxylic acid water reducer,fly ash and granulated blast furnace powder,which were poured and formed respectively.The third,the strain and deformation,crack and failure characteristics of 12 fully regenerated reinforced concrete beam-column members(FRRCBCMs)and 12 ordinary reinforced concrete beam-columns members(ORCBCMs)under different loading conditions were observed,tested and counted for the first time.A series of valuable and meaningful experimental data were obtained.Through in depth and detailed research and analysis,the main results as follows:(1)The quality of fully recycled aggregate concrete made by the new method of the mix proportion design was quite good and its strength was even better than that of ordinary concrete made by natural aggregate.(2)Physical and mechanical tests of reinforced bar(REBAR)were carried out after remediation,straightening and derusting treatment of the abandoned REBAR removed on site.Eligible reinforcement can be used to regenerate concrete components,structures or structural systems.(3)The strength of fully recycled concrete with fly ash plus mixed fly ash and mineral powder were obviously higher than that of ordinary concrete with the same fly ash and mixed fly ash and mineral powder,while the strength of single mixed mineral powder was lower than that of ordinary concrete with the same mineral powder.(4)The failure modes of bending and flexural-shear of fully regenerated reinforced concrete beams were similar to those of ordinary reinforced concrete beams.The rule of strain variation of shear stirrups was increased firstly and then decreases along with the height,but the flexural deflection and ultimate bending moment of the regenerated reinforced concrete beams were larger than that of ordinary beams combined with flexural and shear.Except for the RL-2 beam,flexural-shear composite failure mode of ordinary beams,the abdominal shear oblique main crack of the regenerated reinforced concrete beam was long and flat walnut like,but the crack was a little more and more dense,with larger width and deflection than the ordinary reinforced concrete beam at the same design strength grade,and the development trend of the flexural and shear crack between the two were roughly the same.(5)The conerete strain,steel strain,lateral displacement and damage conditions of fully recycled reinforced concrete column in eccentric compression experiment are similar to that of ordinary reinforced concrete column,but the bearing capacity was larger than ordinary reinforced concrete column.更多还原