陶瓷砖抛光粉在C30混凝土中的应用

陶瓷抛光砖粉是陶瓷抛光砖在生产过程中研磨、抛光产生的废料,其颗粒细小,具有一定的火山灰活性,可用于水泥、混凝土领域。利用陶瓷抛光砖粉替代部分水泥,制备了C30混凝土,重点研究了混凝土的强度和耐久性能。研究结果表明:掺加5%~10%的陶瓷抛光砖粉可改善混凝土的工作性能、提高混凝土各龄期抗压强度,同时混凝土的耐久性也得到显著提高。但当陶瓷抛光砖粉掺量超过20%时,混凝土的力学性能和耐久性均大幅度下降。因此,C30混凝土中陶瓷抛光砖粉掺量应控制在20%以内。     

造孔剂对粉煤灰基多孔陶瓷性能的影响

利用粉煤灰、赤泥为主要原料制备粉煤灰基多孔陶瓷,研究漂珠和氧化铝空心球2种造孔剂对粉煤灰基多孔陶瓷的基本物性和微观结构的影响。SEM显示漂珠制备的粉煤灰基多孔陶瓷中漂珠大部分形成的是闭气孔,而氧化铝空心球颗粒外壳之间相互发生反应,晶体向空心球内部增长,形成较多的连通气孔,影响其保温性能和强度。在造孔剂掺量为15%时,漂珠制备的多孔陶瓷收缩率比氧化铝空心球制备的低6.7%,气孔率高3.7%,性能稳定。     

仿火山渣装饰效果的轻质多孔混凝土制备与性能研究

通过控制调孔剂、粉煤灰掺量来调整相关轻质多孔混凝土的气孔孔径大小和孔径分布,使其具有仿火山渣的装饰效果。基于抗压强度和装饰效果的要求,提出了A08级仿火山渣轻质多孔装饰混凝土的适宜配合比。试验结果表明,按此配合比制备的轻质多孔装饰混凝土不但具有良好的仿火山渣装饰效果,同时具有良好的物理力学性能,多孔混凝土的密度等级为A08级,强度等级达到A5.0级。     

玻璃粉掺量对混凝土抗冻性能的影响

采用平均粒径为21.17μm的玻璃粉,等质量替代水泥10%、20%、30%制备混凝土,研究了玻璃粉掺量对混凝土抗冻性能的影响,并从混凝土孔隙结构和抗拉强度两个角度分析了玻璃粉混凝土冻融破坏的机理。结果表明,掺量为10%时,玻璃粉能有效降低混凝土中有害孔孔隙率,减小最可几孔径,降低孔隙复杂程度,改善孔隙结构。同时,掺入玻璃粉降低了混凝土的抗拉强度。在孔隙改善和强度降低共同作用下,玻璃粉掺量为10%时的混凝土抗冻性能与基准组相似;玻璃粉掺量为20%、30%时,孔隙特征与基准组类似,玻璃粉混凝土抗拉强度随掺量增加降低,造成抗冻性能下降。选用粉煤灰对比研究,发现两者在抗冻性能,孔隙结构和抗拉强度方面有很高的相似性。     

轻质泡沫混凝土的制备及研究

为了减少泡沫破裂、提高早期强度、改善塌模,本文以P·042.5普通硅酸盐水泥作为胶凝材料制备轻质泡沫混凝土,并分别按不同掺量掺入速凝剂、憎水剂,探讨了速凝剂、憎水剂对轻质泡沫混凝土的力学性能、孔隙率、气孔大小与分布及热学性能的影响。结果表明:掺入X速凝剂后轻质泡沫混凝土塌模现象得到了有效的改善,掺量0.4%时,轻质泡沫混凝土的孔隙率达80%以上;掺入4.0%憎水剂,轻质泡沫混凝土的连通孔较少,内部的气孔结构得到了改善。     

掺碎石陶粒多孔混凝土基本性能试验研究

以黏土陶粒、碎石、水泥、Zs-1外加剂等为主要原料,制备了一种高性能陶粒多孔混凝土,通过试验分析了骨料粒径、碎石掺量对陶粒多孔混凝土孔隙率、透水系数、强度等性能的影响,并对其破坏形态、破坏机理进行了分析。结果表明:纯陶粒骨料多孔混凝土的孔隙率为23%~27%,透水系数为6.3~7.1,强度为1~3 MPa在不显著降低孔隙性能的前提下,掺入碎石能有效提高其强度至15 MPa以上;多孔混凝土的强度和孔隙率随骨料粒径的增大而小幅提高,且碎石掺量越大提高效果愈明显。与纯陶粒混凝土相比,碎石掺量为40%~60%、骨料粒径为20~25 mm时,多孔混凝土的强度提高了7倍,而孔隙率仅仅降低了4.2%,此时混凝土基本性能相对最优。     

淄博企业利用陶瓷抛光砖废料制备轻质高强度节能砌块

正淄博市某企业利用陶瓷抛光砖废料,成功研发出轻质高强度节能砌块的技术,山东省住房城乡建设厅节能科技处专家近日在淄博市考察调研建筑节能与绿色建材生产应用情况时,对这项技术给予高度肯定。该技术利用陶瓷抛光砖废料制备轻质高强度节能砌块,首次实现了陶瓷砖抛光废料在蒸压加气混凝土砌块中的大掺量应用,可实现年产150万m3瓷粉蒸压加气砌块或80万m3瓷粉蒸压加气轻质板材,年消化陶瓷砖抛光废料60     

玻化微珠粉煤灰保温混凝土砌块材料性能试验研究

为了进一步降低混凝土导热系数,改善混凝土综合性能,利用轻质集料玻化微珠和粉煤灰,制备玻化微珠粉煤灰保温混凝土。试验研究了不同掺量下玻化微珠和粉煤灰对保温混凝土抗压强度和导热性能的影响,并制作两种截面形式的混凝土砌块进行承载力试验。结果表明,玻化微珠掺量40%、粉煤灰掺量10%时,玻化微珠粉煤灰混凝土较普通混凝土有较好的力学性能和导热性能,利用该掺量配制两种截面形式保温空心砌块其强度均能够达到MU5强度等级。     

半碳化改性秸秆造孔剂对页岩烧结砖的性能研究

秸秆半碳化处理后,作为烧结制品的造孔剂可以制备轻质高强、具有良好保温隔热效果的建筑功能材料。用半碳化秸秆和未经半碳化的秸秆分别作为造孔剂,对比两种造孔剂对多孔烧结砖性能的影响。在相同的烧成制度下,掺加经半碳化处理秸秆的烧结砖试块与掺未半碳化秸秆的试块相比,掺量为20%时,烧成收缩及质量损失分别降低0.6%,0.9%;掺量为15%时,压强为10.3 MPa,满足GB-5101-2003《烧结普通砖》的要求,性能优于未掺半碳化秸秆的试块;而掺入两种造孔剂的试件的气孔率相差无几,为37.2%~43.8%,在相同掺量下,掺加半碳化秸秆的吸水率比掺加未半碳化秸秆降低0.8%,其在烧结砖内所形成的封闭孔数量多。     

利用玄武岩纤维废料的墙体材料母材试配及力学性能研究

本文基于玄武岩纤维废料在轻质墙材中应用所生产的轻集料混凝土自保温砌块,根据轻集料混凝土的配合比设计试配以及试验室现场实际操作,配置出了工作性能较好的轻集料混凝土。通过对比试验,研究了掺合料在不同掺量条件下对轻集料混凝土抗压强度及容重的影响,并进行比较。综合分析了几种掺合料对轻集料混凝土力学性能和容重的影响及其作用规律,从而找到在保证轻集料混凝土强度的前提下,降低容重的配合比设计,为制备玄武岩纤维废料轻质墙材提供重要的参考依据。     

外掺高钙粉煤灰轻集料混凝土力学性能与抗渗性能研究

基于掺加高钙粉煤灰的力学性能与抗渗性能试验,对外掺氧化镁膨胀剂普通混凝土的性能进行研究。分别加入10%、20%和30%的高钙粉煤灰,混凝土早期强度较低,后期强度增长较快,增长率大于未加掺合料的试体。加入高钙粉煤灰可大幅提升混凝土的密实度和孔隙结构,改进混凝土的抗渗性能。高钙粉煤灰的加入促进了轻集料最佳表面结构的形成,使结构更细密,是提高混凝土抗渗性的有效途径。     

稻壳灰替代硅灰对超高性能混凝土性能影响的试验研究

通过对单/双掺活性稻壳灰(RHA)与硅灰(SF)以及RHA的粒径对超高性能混凝土(UHPC)的抗压强度和孔结构影响的研究,得出活性RHA粒径是取代SF的关键.研究结果表明,平均粒径为5.9 μm的R HA能够部分取代SF并应用于UHPC中；在相同总掺量的情况下,复掺RHA与SF的UHPC抗压强度要高于单掺RHA或单掺SF的,并且最佳取代水泥的复掺量为10％RHA与10％SF；在UHPC中掺入RHA能够减少孔体积以及平均孔径,优化孔结构,从而提高UHPC的抗压强度.     

硅藻土、超细稻壳灰、硅灰对双重多孔混凝土性能的影响

通过将硅藻土、超细稻壳灰、硅灰掺入到多孔浆料和多孔轻骨料的双重多孔混凝土中,研究其对双重多孔混凝土性能的影响。结果表明:当掺量为水泥质量的10%时,混凝土强度提高依次是硅藻土提高26%、超细稻壳灰11%、硅灰2.4%,同时也改善了混凝土的保温隔热性能。当含气量在10%~15%时,双重多孔混凝土的强度可在20 MPa以上,导热系数小于0.36 W/(m·K)。用于240 mm厚混凝土墙梁柱时,其平均传热系数Km小于1.5 W/(m·K),满足JGJ 134—2010《夏热冬冷地区居住建筑节能设计标准》的要求。     

轻骨料-水泥石界面区微观结构特征

采用扫描电镜、X射线能谱分析、显微硬度等多种测试方法,测定了不同预饱水程度轻骨料一水泥石界面区水化产物的钙硅比、水泥石显微硬度以及孔结构等微观性能参数,研究了轻骨科预饱水程度对混凝土界面区结构与特征参数的影响,并与普通骨料混凝土进行了对比分析.结果表明,随着轻骨料预饱水程度的提高,界面区厚度从30μm增大至60 μm左右,距界面20μm范围内其显微硬度降低,而大于20μm处则相反,孔结构呈细化趋势,界面区得到增强,明显优于普通混凝土.     

Durability of lightweight concretes with lightweight fly ash aggregates

This paper presents the effects of aggregate properties such as strength, porosity, water absorption, bulk density and specific gravity on the strength and durability of lightweight fly ash aggregate concrete (LWAC). The influence of properties of four aggregates (sintered lightweight fly ash aggregates, cold-bonded lightweight fly ash aggregate and normalweight aggregate) on mechanical and durability properties of concrete is discussed. Experimental results revealed that durable high-strength air-entrained lightweight concretes could be produced using sintered or cold-bonded lightweight fly ash aggregates, having comparable performance with the normalweight concretes. The use of lightweight aggregates (LWA) instead of normalweight aggregates in concrete production decreased the strength and stiffness due to the higher porosity and lower strength of the aggregate included in the concrete. However, permeability of sintered fly ash aggregate lightweight concretes was comparable and slightly lower than normalweight concrete whereas permeability of cold-bonded fly ash lightweight concrete was greater than the others. All concretes had a durability factor greater than 85, which met the requirements by showing quite perfect resistance to freeze–thaw.     

Lightweight concrete made from oil palm shell (OPS): Structural bond and durability properties

The first part of this experimental program was to determine the structural bond properties of lightweight concrete incorporating solid waste oil palm shell (OPS) as coarse aggregate and also to compare its behaviour with other types of lightweight aggregate concretes. Other properties of OPS concrete namely the split tensile strength, modulus of rupture and modulus of elasticity were also determined. The structural bond properties were determined through pull-out test. The results showed that the experimental bond strength of OPS concrete was much higher than the design bond strength as stipulated by BS 8110. In general, the properties of OPS concrete compared well with that of other structural lightweight concretes and the results obtained encourage the use of OPS as aggregates for the production of structural lightweight concrete. The second part of the experimental program investigates the durability performance of OPS concrete through water permeability and water absorption tests.     

再生微粉混凝土抗冻性及抗硫酸盐侵蚀性能研究

以28 d活性指数为85%的再生微粉按胶凝材料10%、20%、30%加入混凝土中,进行了再生微粉混凝土冻融循环试验及抗硫酸盐侵蚀性能研究。试验结果表明,再生微粉掺量低于20%时,掺量越高,混凝土的抗冻性能越好;通过SEM结果发现,混凝土冻融损坏是因水分子受冻膨胀导致钙矾石结晶裂缝和骨料与晶体间裂缝;再生微粉掺量越高混凝土抗硫酸盐侵蚀性能越低,且随着侵蚀时间的增加,该效果更加显著;EDS结果表明,干湿循环破坏的混凝土内部S元素急剧增加,形成的碳硫硅钙石膨胀导致混凝土内部产生结构裂缝是混凝土损伤的主要原因。     

Characteristics of mortar and concrete containing fine aggregate manufactured from recycled waste polyethylene terephthalate bottles

This paper presents the development of lightweight aggregate concrete using fine aggregate that is manufactured from recycled waste polyethylene terephthalate (PET) bottles. Investigations on waste PET lightweight aggregate concrete included three phases: examination of the properties of waste PET lightweight aggregates (WPLA), analysis of the properties of mortar when WPLA was used as fine aggregate, and analysis of the properties of concrete when WPLA was used as fine aggregate. The results of the first phase showed that the WPLA had a density of 1390 kg/m³, a water absorption of 0% and a bulk density of 844 kg/m³. WPLA fineness modulus (F.M.), however, was 4.11, which is higher than the F.M. of river sand. This is because the WPLA was single graded. The results of the second phase showed that for the mortar, in which the WPLA was used as a fine aggregate, the flow value increased, while the compressive strength decreased proportionally to the addition of WPLA with elapsed time. In addition, the amount of water absorption by unit area was higher than for the control mortar (without WPLA) when the WPLA content was either 40% or 60%. For the third phase, the results showed that the slump of the WPLA concrete increased as the WPLA content increased regardless of the water-cement ratio (W/C). In comparison to the control concrete, the 28-day WPLA concrete compressive strength decreased by 5%, 15% and 30%, with an increase of WPLA content of 25%, 50% and 75%, respectively. In addition, for a W/C of 0.49, the structural efficiency (compressive strength/density ratio) of the concrete containing 25% of WPLA was higher than that for the control concrete.     

Valorization of coarse rigid polyurethane foam waste in lightweight aggregate concrete

This study examines the mechanical properties and the durability parameters of lightweight aggregate concretes (LWAC) incorporating rigid polyurethane (PUR) foam waste as coarse aggregates (8/20 mm). The influence of both the increasing incorporation of PUR foam waste and the presence of superplasticizer on the workability, bulk density, mass loss, drying shrinkage, compressive strength, dynamic modulus of elasticity, total porosity, gas permeability and chloride diffusion coefficient of the different concretes, has been investigated and analyzed. The results showed that the use of PUR foam waste enabled to reduce by 29–36% the dry density of concrete compared to that of the normal weight concrete (made without foam waste). The reduction of density was due to the increase of total porosity in the lightweight concretes, which also induced higher gas permeability and chloride diffusion coefficient. These negative effects on durability of concrete were lowered by improving the characteristics of the cementitious matrix. The mechanical properties of the LWAC ranged between 8 and 16 MPa for the compressive strength and between 10 and 15 GPa for the dynamic modulus of elasticity; the concrete mixture with the higher performances almost satisfied the mechanical and density criteria of structural lightweight concrete. These results consolidate the idea of the use of PUR foam waste for the manufacture of lightweight aggregate concretes.