不同成孔机理造孔剂对粉煤灰页岩烧结制品性能影响

矿物内燃造孔剂可以在高温下释放能量,促进试件的烧成,试件的烧成收缩率高,抗压强度损失率低（44．7％）,试件的气孔率低、体积密度高。热分解型造孔剂高温下吸热分解,试件的烧成收缩尺寸控制效果最好,制品的强度较低,气孔率高于其它两组试样,体积密度值最低。生物质造孔剂在烧成过程中可以为试件提供能量,但由于形成的缺陷尺寸大,掺量体积比为10％的试件的强度损失率最大,达到69．5％。     

粉煤灰页岩烧结制品的微孔造孔技术研究

以粉煤灰和页岩为主要原材料,通过对试件烧成收缩、抗压强度、体积密度、显气孔率、导热系数等的分析,研究了内燃型、热分解型、热致收缩型、复合型4类9种造孔剂对烧结制品性能的影响。结果表明:内燃型造孔剂M的掺加降低了试件的烧成收缩,随着M掺量增加,试件显气孔率升高、体积密度降低;热分解型造孔剂D和热致收缩型造孔剂Z可以有效的控制试件的烧成收缩,降低体积密度,并增加显气孔率和吸水率;复合掺加M、Z两种造孔剂后试件尺寸收缩和质量损失稍有增加,显气孔率和吸水率略有降低;微孔造孔技术可增加显气孔率,降低体积密度和导热系数,改善烧结制品的热工性能。     

锯末造孔剂对粉煤灰页岩烧结制品性能的影响

锯末具有高发热量及烧失量的特点,可以作为造孔剂制备轻质高强多孔保温烧结制品。在相同的烧成制度下,粉煤灰页岩烧结制品空白试件的显气孔率和吸水率分别为35.75%、1.41g/cm3;锯末的掺入能有效地抑制试件的烧成收缩,掺入试件体积比10%、粒径0.15mm~0.3mm锯末的试件显气孔率和体积密度分别为42.43%、1.32g/cm3;锯末粒径增大至0.3mm~0.6mm时,试件显气孔率减小至42.04%,体积密度增大至1.37g/cm3;SEM分析表明锯末造孔剂的掺入使得试件微观结构疏松、多孔。     

秸秆造孔剂对页岩烧结微孔砖工艺性能的影响研究

以页岩和秸秆造孔剂作为原材料,探究不同掺量、不同粒径范围的秸秆造孔剂对页岩烧结微孔砖在抗压强度、体积密度、吸水率、显气孔率等方面的影响规律。试验结果表明:随着秸秆粉末掺量的增多和粒径的增大,试件标准稠度用水量增多,抗压强度降低和体积密度降低,显气孔率升高。通过控制秸秆粉末的掺量和粒径,能有效地改善页岩烧结砖的各项性能。     

掺陈化粮对烧结多孔材料性能的影响

利用陈化粮作为成孔剂制备轻质高强高孔洞率的烧结墙体材料,系统研究了成孔剂掺量和粒径对烧结制品性能的影响。结果表明：在相同烧成制度下,掺加试样质量比15%的0.15 mm~0.3 mm陈化米粒径的试件体积密度降低为1.35 g/cm3,气孔率达到45.89%,制品气孔率提高了83%,抗压强度为18.56 MPa;随着气孔率的增大,抗压强度降低,当气孔率大于35%时,成孔剂的粒径对抗压强度影响明显,当气孔率小于35%时,烧结制品性能相对稳定。     

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。     

几种不同造孔剂制备烧结保温材料性能研究

利用造孔剂厌氧污泥、锯末和兰炭末分别制备烧结保温材料,对比三种制品的性能。首先对原料的物理化学性能进行分析研究,结果表明,重庆地区的页岩适宜作为制备墙体材料的掺配料,最佳烧成温度为950℃;厌氧污泥、锯末和兰炭末均具有高发热量和高烧失量等特点;其次,将三种不同的造孔剂按一定的比例与页岩混合、成型、烧结,检测制品的显气孔率、体积密度和抗压强度。结果表明,适当的造孔剂的掺入量,以兰炭末为造孔剂的制品综合性能为最优。     

篦冷机矮墙用耐火浇注料的试验研究

这里针对干法水泥烧成系统中篦冷机矮墙部位的工况条件及其对耐火材料的性能要求,以棕刚玉、高铝矾土为骨料,通过改变结合剂的种类和加入量,研究了它们对浇注料性能(气孔率、体积密度、烧成线变化、力学强度)的影响。     

利用煤矸石及废陶瓷制备泡沫陶瓷的研究

以山西省阳泉市的煤矸石和废弃陶瓷为主要原材料,添加长石为助熔剂,碳酸钙当作造孔剂,在不同温度下烧结制备煤矸石泡沫陶瓷。实验结果表明:随着烧成温度的提高,煤矸石泡沫陶瓷的气孔率呈现先增加后减小的趋势,在1000℃时气孔最多,显气孔率达57.1%。随着烧成温度的增加,多孔陶瓷的抗压强度逐渐降低,最大可达34MPa。     

低硅铁尾矿制备建筑陶粒及其性能研究

以低硅铁尾矿为主要原料,黏土为粘结剂,煤粉和KD粉为造孔剂,对铁尾矿建筑陶粒配方进行了研究,并以筒压强度、吸水率、堆积密度和显气孔率为主要指标考察了造孔剂选择、物料配比和焙烧工艺对烧成陶粒性能的影响。结果表明:铁尾矿建筑陶粒原料铁尾矿、黏土、煤粉和KD粉的适宜质量配比为83:8:3:6,铁尾矿利用率高达80%以上;在焙烧温度1160℃和保温时间60min的条件下,烧成陶粒符合GB/T 17431.1—2010《轻集料及其试验方法》中900级轻粗集料的技术要求;微观SEM图像显示陶粒内部疏松多孔,XRD图像表明焙烧过程中生成了硅酸盐类新物质碱玄岩。     

成孔剂对烧结页岩砖性能的影响

选用锯末、煤矸石和造纸污泥作为烧结页岩砖的成孔剂,系统研究不同成孔剂的热解特性及其对页岩烧结砖的可塑性、体积密度、抗压强度、显孔隙率、吸水率等性能的影响。结果表明：随着锯末掺量的增加,烧结砖中孔隙数量增加,同时其体积密度和强度迅速下降,吸水率增加,因而掺量应控制在6%以内;煤矸石可塑性较差,烧失量较小,烧结页岩砖的孔隙率低,从而导致其吸水率低,体积密度和强度降低幅度都较小,实际生产中可根据内燃砖发热量和可塑性要求,适量掺加煤矸石;造纸污泥的可塑性较好,随着掺量增加混合料的可塑性变大,但掺量过大成型搅拌困难     

Effect of high temperature on strength and microstructural properties of cemented paste backfill

The main purpose of this research is to investigate the influence of high temperatures on the strength and microstructure (e.g. pore structure, porosity) of cemented paste backfill (CPB) through a series of experimental tests. A laboratory experimental setup allowing the simulation of various high-temperature conditions is developed. Different types of CPB specimens are exposed to different high temperatures (100, 200, 400 and 600 °C). The strength, porosity, pore size distribution and water absorption of these CPB specimens are then evaluated by laboratory tests. Thermogravimetric and differential thermal analyses are also performed to study the thermal behaviour of the CPBs exposed to high temperatures. The results show that high temperatures have a significant effect on the properties of CPBs. Generally, increasing temperatures up to 200 °C leads to higher strength in most types of CPB studied. The porosity and pore size distribution of the CPBs change only slightly. Above 200 °C, the temperature reduces the strength of the CPBs. The most notable strength decrease takes place at exposure temperatures exceeding 400 °C. The significant decrease of the strength of the CPB is accompanied by a significant change in the microstructure (porosity, pore size distribution, mineral phases). Moreover, the effect of high temperatures on the strength and microstructure of CPBs depends on the water/cement ratio (w/c ratio) and the tailings type.     

低成本大流动度轻质高强页岩陶粒混凝土研究

基于页岩轻质陶粒与普通混凝土材料,采用体积法设计配合比,以低成本为目标配制大流动度、轻质高强混凝土.利用水胶比,陶粒、砂及浆体{者比例调控试体坍落度、表观密度与强度.町筛选出满足人流动度的轻质高强混凝t,通过对比实验,得到28 d抗压强度超过60 Mpa,表观密度为2025 kg/m3的陶粒混凝土.     

Impact of melting and burnout of polypropylene fibre on air permeability and mechanical properties of high-strength concrete

This study intends to investigate the impact of high temperature, melting and burnout of Polypropylene Fibre (PP fibre) on mechanical properties, pore size distribution and air permeability of high strength concrete. The specimens were high-strength concrete with 120 MPa strength produced with a water-binder ratio of 20%. To examine the effects of melting and burnout of the PP fibre, the experiment was conducted using two mixtures. One mixture contained 1.5 kg/m³ of PP fibre, while the other did not contain any PP fibre. Heating temperatures were set to room temperature (RT), 120, 200, 300 and 400 °C, considering the temperatures for the melting and burnout of the PP fibre. After heating and cooling, compression tests were carried out on the concrete specimens to measure the modulus of elasticity and Poisson's ratio. Pore size distribution was measured using the fragments created by the compression tests. Air permeability was estimated by measuring the pore size distribution. It was found that melting and burnout of the fibre did not affect the compressive strength and modulus of elasticity but the Poisson's ratio of the specimens containing fibres increased at 400 °C. The effect of melting and burnout of fibre on pore volume and air permeability is quite small. If it is assumed that micro-cracks affected the air permeability, it is expected that high strength concrete with a large fibre content should create many micro-cracks at high temperature, leading to an increase of air permeability.     

纤维增强超高强混凝土防高温爆裂研究

对15组立方体抗压强度为116~143MPa纤维增强超高强混凝土(FRUHSC)试件,开展了ISO834火灾标准升温曲线下的高温爆裂试验,考察了水胶比、孔隙率、纤维类型及体积分数、试件尺寸对其高温爆裂的影响.结果表明:水胶比为0.15的超高强混凝土与水胶比为0.18时相比,具有更低孔隙率和更高强度,表现为爆裂程度更高;为改善常温下混凝土延性而掺入体积分数1.00%的熔抽超细型钢纤维并不能防止其高温爆裂;掺入体积分数0.15%的聚丙烯纤维可防止Φ100×200mm试件高温爆裂,并适用于Φ300×300mm试件.对水胶比为0.15、混掺体积分数为0.15%聚丙烯纤维及0.50%熔抽超细型钢纤维的超高强混凝土型钢组合柱进行高温加载试验后发现,型钢外包混凝土未发生高温爆裂,表明所建议的混掺纤维体积分数在构件受荷时可防止高温爆裂.     

赤泥高强陶粒的研制

利用拜耳法赤泥、页岩和粉煤灰等原料制备的高强陶粒,赤泥掺入量最高50%,陶粒堆积密度840kg/m3,筒压强度达到7.5MPa,强度标号45MPa,吸水率6.9%,表观密度1000kg/m3,孔隙率16.0%,放射性能够满足作为轻集料的活度要求;还利用了XRD、SEM等分析方法,对赤泥陶粒烧结机理进行了探讨。     

固硫灰对水泥基自流平砂浆水化产物和性能的影响

研究了固硫灰细度和掺量对水泥基自流平砂浆性能的影响.研究发现固硫灰细度越细,砂浆1d、3d、28d抗折和抗压强度越高,收缩则先减小后增大.掺加粉磨后固硫灰砂浆的收缩均较掺原灰砂浆的收缩小.随着固硫灰掺量增大,水泥基自流平砂浆的1d和3d强度先增大后减小,28d强度呈减小趋势,收缩随着固硫灰掺量增大而减小.固硫灰取代硅酸盐水泥的40%～60%时,砂浆的强度和收缩性较好,取代率为50%时性能最佳.     

桥面用丁苯乳液改性水泥砂浆物理性能的研究

通过测定新拌砂浆保水性、含气率,硬化砂浆孔隙率、孔径分布、断面形貌以研究丁苯乳液D623对砂浆物理性能的改性效果,丁苯乳液D623对砂浆有良好的保水和引气作用,可使砂浆体积密度降低,孔径分布改变;聚合物成膜后形成网状结构,与水泥水化产物相互穿透;硬化砂浆的孔隙率与新拌砂浆的含气率没有对应关系,与新拌砂浆的体积密度反倒有一定的关系;砂浆抗压强度、抗折强度和弹性模量均与孔隙率、体积密度有对应关系,而粘结抗拉强度与它们的关系则不明确。     

Application of spent grains to increase porosity in bricks

The dumping of spent grains is going to be more difficult because of the increasing number of cattle. That means new ways of dumping must be developed.The goal of the work was to test the technical properties of bricks produced with spent grains added to increase porosity.The flexural strength of the fired samples remained at 8.5 MPa; the air-dried samples exhibited a small increase in flexural strength. The shrinkage and true density were almost identical, while the raw density, capacity for water absorption and open porosity showed minor differences.In the large-scale experiment no problems were observed during the production. The bricks produced with spent grains possessed a comparable or higher strength, a higher porosity and a reduced density after firing than those from a standard production clay. Because of the lower sintering temperatures the fired clay product was more strongly sintered, exhibiting both greater strength and higher porosity.