共查询到16条相似文献,搜索用时 125 毫秒
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在系统测试不同粒级黏土砖再生骨料表观密度、堆积密度、1h吸水率、孔隙率、空隙率等物理性质变化规律的基础上,测试黏土砖再生骨料混凝土抗压强度和砂浆抗折强度、折压比随龄期的变化,通过对3组不同水泥用量黏土砖再生骨料混凝土和陶粒混凝土不同龄期抗压强度的比较,得出因黏土砖再生骨料物理和低强度特性,与可比较的陶粒混凝土相比,其混凝土表观密度大,抗压强度低,黏土砖再生骨料低强度特性在高水泥用量或后龄期时对混凝土强度的不利影响更明显。 相似文献
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再生骨料基本性质及对混凝土性能影响的研究 总被引:11,自引:0,他引:11
系统研究了废弃混凝土经破碎、分级、清洗后得到的再生骨料的基本性质,揭示了再生骨料较天然花岗岩骨料密度小、空隙率大、吸水率和吸水速率大及压碎指标大等特点。同时还讨论了再生骨料对新拌混凝土和易性和抗压强度的影响规律,再生骨料将使新拌混凝土的流动性降低,但粘聚性和保水性较好,使硬化混凝土的抗压强度略有降低。 相似文献
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采用正交设计方法设计试验,从而配置再生骨料透水性混凝土。以再生骨料透水性混凝土的抗压强度、透水系数、孔隙率为主要考核指标,分别研究了水灰比、骨灰比、砂率、再生骨料粒径等因素及其不同的水平对再生骨料透水性混凝土各性能指标的影响。并对各考核指标的主要影响因素进一步细分,结果表明,再生骨料透水性混凝土的透水系数和孔隙率的主要影响因素是水灰比;抗压强度的主要影响因素是骨灰比。水灰比的变化与透水系数和孔隙率之间呈现相同的规律,都出现先上升后下降的趋势;骨灰比的变化与抗压强度之间呈现线性下降的趋势。当水灰比介于0.37~0.43之间,骨灰比介于4.0~4.5之间时,混凝土拌和物和易性较好,混凝土的强度较高,透水性较好。 相似文献
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道路拆除的建筑垃圾中包含大量的钢筋以及混凝土、砖瓦物料,采用"分拣-破碎-筛分-制砖-烘干"模式进行建筑垃圾再生利用,制作空心砖、泡沫混凝土材料,道路拆除的建筑垃圾再生骨料可以取代砂子,用于砌筑砂浆、抹灰砂浆。通过对道路拆除中建筑垃圾的再生利用,有效减少了垃圾对环境的污染,避免了建筑垃圾对土壤和环境的破坏,同时还具有客观的经济效益,研究建筑垃圾再生利用实施模式,从处理技术和利用模式上进行革新,提高建筑垃圾的使用范围,促进环境了环境与经济效益的协同增长。 相似文献
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An increasing trend towards the use of sustainable processes has led to recycled materials being incorporated into concrete. It is generally recognised that crushed recycled construction aggregate material produces concrete of a lower compressive strength, when used as an aggregate replacement due to deleterious materials within the aggregate.It is generally accepted that in the UK, freeze/thaw attack is, after chloride-induced corrosion, the most common cause of concrete deterioration. This paper addresses the freeze/thaw durability of recycled aggregate concrete using a paired comparison test based upon weight loss and final compressive strength.Recycled aggregate concrete was found to be of at least equal durability to concrete manufactured with virgin aggregates. This was due to careful selection of the replacement aggregate and treatment prior to batching.Durability is an important material property and recycled aggregates need to be widely tested to gain confidence for use within the industry and this work shows future possibilities. 相似文献
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Fernando Pelisser Nilomar Zavarise Tiago Arent Longo Adriano Michael Bernardin 《Journal of Cleaner Production》2011,19(6-7):757-763
The present work deals with the investigation of the potential use of recycled tire rubbers in cement matrices. This facilitates the development of concrete with a lesser environmental impact. Thus, it contributes to developing construction in a sustainable way. Concrete formulations were produced with the replacement of 10% sand aggregate by recycled tire rubber using conventional rubber and rubber modified with alkaline activation and silica fume addition to improve the mechanical properties. The water/cement ratio (or composition) and the testing age were used as additional variables. The concrete characterization was performed by testing the compressive strength, elastic modulus, density and microstructure (SEM). The recycled tire rubber proved to be an excellent aggregate to use in the concrete. It was observed that its compressive strength was reduced by only 14% (28 days), in comparison to the conventional concrete, reaching 48 MPa for the mixture with higher resistance. The concrete compositions were found to be lighter and a reduced interface was observed between the rubber and cement matrix after the chemical treatment. The rubberized concrete can support construction sustainability, minimize the consumption of natural resources by using an industrial residue and produce a material with special features. 相似文献
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Recycling and reuse of waste such as building rubble, concrete lumps, etc. generated at construction and demolition sites form part of a wider, complex issue, primarily relating to improving supplies of construction material and solving problems of disposal of waste construction material. Within the framework of the sustainable development of the environment, the use of waste materials with minimum environmental impact has received much attention. The conversion of a large amount of demolished waste into an alternative resource will conserve the depleting natural resources of building materials. Demolished waste is mainly used as a non-stabilized base or sub-base in highway construction. The present paper discusses the recycling process and makes an effort to assess a safe and economic use of recycled concrete as a structural grade material for the construction industry. Extensive tests of structural properties such as compressive strength, flexural strength and split tensile strength of recycled concrete were carried out, in which cement and similarly fine aggregate were partially replaced by demolished waste to obtain recycled concrete and recycled aggregate concrete whose properties were compared with results for the conventional concrete. 相似文献
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基于生命周期评价方法,考虑混凝土重复再生利用的环境影响分配,对重复再生混凝土的性能和环境影响进行研究,并基于功效系数法优化出混凝土最佳重复再生次数.研究结果表明,再生混凝土的坍落度,强度和电通量随着重复再生循环次数的增加而下降,经3次重复再生后,混凝土28d立方体抗压强度为33.3MPa,满足设计要求,而坍落度和电通量与普通混凝土相比,分别减小和增大了38.9%和85.7%;混凝土材料的生态效率随着混凝土重复再生次数的增加而提高,混凝土材料的GWP、CED和CMR的值均随着混凝土重复再生次数的增加而降低,降低幅度从高到低依次为:CMR > GWP > CED;综合考虑混凝土的坍落度,混凝土抗压强度、电通量、GWP、CED和CMR等6个指标,4种混凝土配合比情景中,混凝土总功效系数从高到低依次为:一次再生混凝土 > 二次再生混凝土 > 三次再生混凝土 > 普通混凝土. 相似文献
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研究了废混凝土粉以不同取代率取代建筑砂浆中的天然砂对砂浆的和易性及强度的影响 ,结果表明 ,废混凝土粉可以取代建筑砂浆中的部分天然砂配制再生骨料砂浆。 相似文献