DM1型模数多孔砖力学性能研究

通过时多孔砖与普通砖砌体的抗剪、抗压强度对比试验研究,得出了多孔砖砌体在抗剪强度、弹性模量等方面均优于普通砖砌体的结论,同时给出了多孔砖砌体的弹性模量建议公式。本文为推广应用模数多孔砖提供了科学依据。     

砂浆片局压法推定混凝土砖砌体中砂浆强度的试验研究

现行国家标准GB/T50315—2011《砌体工程现场检测技术标准》所列各技术方法仅适用于烧结普通砖及烧结多孔砖砌体中砂浆强度的推定,而混凝土普通砖与多孔砖砌体中砂浆强度的现场检测方法目前缺乏相应的标准依据。通过采用砂浆片局压法推定混凝土普通砖与多孔砖砌体中砂浆强度的试验研究,验证砂浆片局压法推定烧结普通砖砌体中砂浆强度的换算公式,并提出砂浆片局压法推定混凝土普通砖和多孔砖砌体中砂浆强度的换算方法及测强公式。     

烧结页岩煤矸石多孔砖砌体抗剪强度试验研究

介绍了两种孔型烧结页岩煤矸石多孔砖砌体的通缝抗剪强度试验概况与结果,探讨了多孔砖砌体的抗剪机理。通过试验数据的分析,得出了多孔砖砌体通缝抗剪强度的计算公式和抗剪强度指标,与现行规范规定的设计值相比平均高47%。     

再生混凝土多孔砖砌体抗剪强度试验研究

通过试验研究了再生混凝土多孔砖砌体的抗剪强度。试验结果表明:再生混凝土多孔砖采用半盲孔设计,提高了砖和砂浆的粘结性,大大增加了剪切面积;砂浆的销键作用能有效提高砌体的抗剪强度;再生混凝土多孔砖砌体的抗剪强度高于烧结普通砖、烧结多孔砖砌体、混凝土空心砌块砌体的抗剪强度。提出了再生混凝土多孔砖砌体的抗剪强度计算公式和设计值的建议取值:再生混凝土多孔砖砌体的抗剪强度平均值计算公式为:fV,m=0.142!f2,砌体的抗压强度设计值f为:f=0.35fV,m。     

烧结污泥页岩多孔砖砌体本构关系北大核心CSCD

为研究不同污泥掺量下烧结污泥页岩多孔砖砌体受压变形性能、抗压强度、峰值应变和弹性模量,建立本构关系,对用两种水泥砂浆和四种污泥掺量的烧结污泥页岩多孔砖砌筑的36个试件进行轴压试验,实测了试件的应力-应变曲线、抗压强度、峰值应变和弹性模量。结果表明,烧结污泥页岩多孔砖砌体抗压强度和弹性模量随污泥掺量的增加而逐渐降低,并低于普通页岩烧结多孔砖,峰值应变与普通页岩烧结多孔砖相同。通过分析砌体受压破坏的过程和实测应力-应变曲线,结合砌体的力学损伤,将砌体损伤演化方程考虑为一个含初始损伤值的损伤函数,以此建立了砌体受压的本构关系模型。该模型所确定的烧结污泥多孔砖砌体的本构关系曲线不仅与试验数据吻合,还克服了已有本构关系的不足。对于不同材料的砌体,结合抗压试验确定模型中的相关参数,可得到相应的本构关系表达式。     

非烧结多孔砖砌体强度估值模型及抗压强度研究

为了研究不同块型非烧结多孔砖砌体的抗压强度,通过试验研究,对Tasuji-Slate-Nilson破坏准则进行修正后,结合ANSYS有限元分析,得到了分析各种块型砌体抗压强度的理论模型。用该模型对各种块型砖砌体分析结果表明,块体原材料、几何尺寸和孔洞率对砌体抗压强度有明显的影响。在普通砖砌体抗压强度计算公式基础上,引入块型影响系数,得到了各种块型非烧结多孔砖砌体抗压强度计算公式。通过与493个蒸压灰砂多孔砖砌体、144个混凝土多孔砖砌体及30个蒸压粉煤灰多孔砖砌体抗压试验结果对比表明,计算公式的计算精度良好。     

混凝土多孔砖的砌体力学性能及应用

本文试验研究了混凝土多孔砖砌体力学性能。试验结构表明,当采用M10的混合砂浆砌筑MU15的多孔砖时,砌体轴心抗压强度、抗剪强度及通缝和齿缝弯曲抗拉强度均高于同强度等级的烧结多孔砖,且远高于《砌体结构设计规范》(GB50003—2001)中烧结多孔砖砌体的标准值和设计值要求。多项试点工程表明,除了因吸水率较小,粉刷掉灰相对较多外,其他性能均与烧结多孔砖相似。     

烧结普通砖和烧结多孔砖的石灰爆裂

对烧结普通砖和烧结多孔砖石灰爆裂的形成和消除方法作了比较全面的论述，对烧结砖厂有参考价值。     

烧结页岩煤矸石多孔砖砌体抗压强度试验研究

对圆形孔烧结页岩煤矸石多孔砖砌体的受压性能进行了试验研究。圆形孔烧结多孔砖砌体的受压破坏过程及形态与普通实心标准砖砌体类似,但呈现出更明显的脆性破坏特征,其抗压强度高于现行规范值。分析了4种强度等级的砖与5种强度等级的砂浆配砌的20组(80个)砌体抗压试件的试验结果。提出了抗压强度平均值的建议公式,并与矩形条孔多孔砖砌体的试验结果以及现行规范的抗压强度指标作了对比。     

准GERIG干燥窑

天津建工页岩制品有限公司于2003年建成了两条年产6000万块（折普通砖）页岩烧结多孔砖牛产线。2006年公司开始对其中一条生产线进行技术改造，经过公开招标，选定由法国CERIC公司进行技术总承包。该技术改造项目已于2006年末建成投产，以生产2000mm×1000mm×50mm烧结路面砖为主，设计年产量为3500万块。     

Quasi-static and high cycle fatigue strength of brick masonry

Quasi-static and high cycle fatigue tests have been conducted on brick masonry test specimens under laboratory dry, wet and submerged test conditions. The relatively low compressive strengths of the bricks and mortar used to manufacture the test specimens were intended to be representative of the type of bricks and mortar likely to be encountered in relatively old masonry arch bridges. The quasi-static test results indicate that the compressive strength of brick masonry increases with an increase in the compressive strength of the mortar, and decreases with an increase in the degree of saturation. The compressive strength of brick masonry, based on assumed linear no tension stress distributions, increases with an increase in the load eccentricity or stress gradient. Approximately 20% of the apparent increase in compressive strength due to load eccentricity can be attributed to non-linear material behaviour, resulting in non-linear no tension stress distributions in the mortar joints. The high cycle fatigue tests on laboratory dry, wet and submerged test specimens indicate that the fatigue strength of brick masonry depends upon the induced stress range, the mean or maximum induced stress and the quasi-static compressive strength of the brick masonry under similar loading conditions. A lower bound fatigue strength curve for laboratory dry, wet and submerged brick masonry is proposed.     

回弹法推定砌体中烧结多孔砖抗压强度研究

通过6组烧结多孔砖标准砌体试件中的回弹对比试验,研究了多孔砖在不同约束条件和竖向压力下的回弹值的影响因素。通过对试验数据进行对比研究和回归分析,提出了回弹法检测砌体中烧结多孔砖抗压强度的统一公式,验证性试验的结果显示该公式检测精度较高,可为相关标准、规范的修订提供依据。     

Externally bonded grids as strengthening and seismic retrofitting materials of masonry panels

Externally bonded grids are used in this study as a means of increasing the load-carrying and deformation capacity of unreinforced masonry (URM) walls subjected to cyclic loading. The experimental investigation was carried out on two groups of medium-scale, single-wythe wallettes consisting of either perforated fired clay bricks, or solid stone blocks. The specimens were subjected to cyclic loading which induced in-plane flexure combined with axial force, out-of-plane flexure and in-plane shear with axial force. The parameters considered were the number of strengthening layers (one or two layers, applied on both sides), the type of grid (open mesh structures comprising carbon, glass or basalt fibers and polypropylene or polyester), the type of bonding agent (mortars of different compositions or epoxy resin) and the compressive stress level applied to specimens undergoing in-plane loading. Based on the findings of this work the use of externally bonded grids comprises a promising solution for the structural upgrade of existing masonry structures.     

蒸压灰渣页岩砖砌体抗压及抗剪性能试验研究

通过对3种砂浆砌筑的24件蒸压灰渣页岩砖砌体试件的轴心抗压试验与通缝抗剪试验,分别对该砌体在轴心压力与剪力作用下的抗压性能与抗剪性能进行试验研究,分析了该砌体的破坏特征、抗压能力与抗剪性能。研究表明：轴压试验中,与黏土砖相比蒸压灰渣页岩砖砌体的初始裂缝出现较早,砌体的抗压强度随着砂浆强度的提高而提高。砌体通缝抗剪试验试...     

Experimental study on basic mechanical properties of DP-type fired perforated clay brick masonry

DP型烧结多孔黏土砖的孔型和孔洞率相比普通多孔砖有所变化,为研究对应砌体的力学性能与变形指标,对DP型烧结多孔黏土砖砌体进行了受压和受剪试验,根据试验结果分析了该类砌体受压、受剪的破坏机理和破坏特征。结果表明,大开孔率烧结多孔黏土砖砌体受压破坏时沿竖向形成上下通缝,开孔率较大的DP1型烧结多孔砖砌体的抗压强度比开孔率较小的DP2型烧结多孔黏土砖砌体的低,且变异系数大;砌体破坏形式包括单剪破坏、双剪破坏和砖块压坏三种,DP1型烧结多孔砖砌体抗剪强度比DP2型烧结多孔黏土砖砌体的高。采用最小二乘法对规范公式进行修正,建立了DP型烧结多孔黏土砖砌体抗压和抗剪强度平均值的计算式,计算结果与试验结果吻合较好。计算得到DP型烧结多孔黏土砖砌体抗压和抗剪强度设计值,并根据已有受压本构模型,建立了该类砖砌体受压应力-应变关系式和弹性模量计算式,计算值与试验结果吻合较好。     

回弹法检测砌体中混凝土砖抗压强度技术的研究

近年来,混凝土砖正以其生产能耗低、节土利废等特点而为建设工程所广泛应用,随之而来的将是对既有建筑物或构筑物砌体中混凝土砖的抗压强度的检测提出了要求.本文主要介绍了江苏地区采用回弹法检测砌体中混凝土砖抗压强度技术的研究情况.     

表面带凸凹槽蒸压粉煤灰砖砌体受力性能的试验研究

通过对不同强度等级砂浆砌筑的表面带凸凹槽蒸压粉煤灰砖砌体的受剪和受压性能试验,对其抗剪和抗压强度进行了分析。结果表明,表面带凸凹槽蒸压粉煤灰砖砌体的抗剪和抗压强度均不低于粘土砖砌体相应的强度,在抗震设计中可按粘土砖房的相应规定执行,扩大了蒸压粉煤灰砖在地震区的应用范围。     

页岩烧结保温砌块砌体基本力学性能试验研究

通过对页岩烧结保温砌块砌体轴心抗压、沿通缝抗剪、剪压复合抗剪性能试验研究,分析其破坏特征和破坏机理。试验结果表明:页岩烧结保温砌块砌体受压破坏时,在竖向灰缝附近形成主裂缝,接近极限荷载时砌体出现表皮剥落现象;沿通缝抗剪破坏模式主要为单剪破坏,脆性明显;剪压破坏有剪磨、剪压和斜压3种类型;实测轴心抗压强度平均值高于规范值,沿通缝抗剪强度、复合抗剪强度平均值低于计算值,并分别给出砌体轴心抗压强度平均值、抗剪、剪压复合受力抗剪强度平均值建议公式;剪压复合抗剪强度随着压应力的增大而增大;建立了页岩烧结保温砌块砌体受压应力应变关系表达式;给出该类砌块的弹性模量和泊松比的建议值。     

Use of recycled aggregates in molded concrete bricks and blocks

This study aimed to develop a technique for producing concrete bricks and paving blocks using recycled aggregates obtained from construction and demolition waste. Laboratory trials were conducted to investigate the possibility of using recycled aggregates from different sources in Hong Kong, as the replacement of both coarse and fine natural aggregates in molded bricks and blocks. A series of tests were carried out to determine the properties of the bricks and blocks prepared with and without recycled aggregates. The test results showed that the replacement of coarse and fine natural aggregates by recycled aggregates at the levels of 25 and 50% had little effect on the compressive strength of the brick and block specimens, but higher levels of replacement reduced the compressive strength. However, the transverse strength of the specimens increased as the percentage of replacement increased. Using recycled aggregates as the replacement of natural aggregates at the level of up to 100%, concrete paving blocks with a 28-day compressive strength of not less than 49 MPa can be produced without the incorporation of fly ash, while paving blocks for footway uses with a lower compressive strength of 30 MPa and masonry bricks can be produced with the incorporation of fly ash.