共查询到19条相似文献,搜索用时 500 毫秒
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为确立深门特大桥C40混凝土抗压强度值与回弹值之间的换算关系,让回弹值与试件抗压强度值更加接近,对抗压强度值与回弹值之间进行不同函数模拟,对多种回归方程的平均相对误差和相对标准差进行对比,建立深门特大桥专用测强曲线。 相似文献
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回弹法是常用混凝土强度的无损检测方法。但随着混凝土向高强度、高性能和特殊性能绿色混凝土(CHIC)方向发展,大量掺和料、化学外加剂使用,使得混凝土表面质量和内部质量存在差异,因此其测试结果误差较大。文中结合涡河四桥空心板梁强度检测,分析回弹法检测泵送商品混凝土强度的方法、存在的问题及原因,并建议对回弹法检测混凝土抗压强度技术规程的相关内容修正、完善。 相似文献
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基于模糊系统方法的混凝土强度预测模型 总被引:1,自引:0,他引:1
采用单值模糊器、乘积推理机、中心平均解模糊器,建立了基于模糊系统方法的混凝土无损检测强度评定模型.为了提高模型精度,以回弹值、超声值、碳化深度值和含水率作为模型输入变量,抗压强度值作为模型输出变量,通过一定的数据训练,提取模糊规则,形成完备的模糊规则库.实验结果表明:模糊系统模型预测结果的平均相对误差为7.98%,相对标准差为10.53%.该模型的预测精度明显高于目前常用的回归模型预测精度,基于多因素的混凝土强度评定精度高于基于单因素的混凝土强度评定精度.因此,该方法为混凝土强度检测评定提供了一种有效的途径. 相似文献
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通过室内试验和工程实际应用,研究了基于电化学综合法的混凝土结构中钢筋锈蚀检测与评价技术。首先通过3组试件试验研究不同腐蚀条件、不同测试条件对混凝土电阻率、半电池电位和腐蚀电流密度3种电化学检测结果的影响规律,得到电化学综合法检测混凝土中钢筋锈蚀状况的递进式评定准则。以某高桩码头检测项目为依托,采用电化学综合法对混凝土中钢筋锈蚀状况进行检测,并根据该递进式评定准则对钢筋锈蚀情况进行综合评价。结果表明,基于电化学综合法的混凝土中钢筋锈蚀检测与评价技术可有效提高钢筋锈蚀状况检测的准确性和可靠性。 相似文献
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钢纤维对自密实混凝土力学性能的影响研究 总被引:1,自引:0,他引:1
文中首先根据当地常见原材料和常规工艺对钢纤维自密实混凝土进行了配制,并对拌合物进行了工作性能测试。然后主要对钢纤维体积率对钢纤维自密实混凝土抗压强度、劈拉强度、抗折强度的影响进行了研究,得到钢纤维自密实混凝土28天抗压强度与劈拉强度的线形关系式。 相似文献
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越来越多的混凝土构件检测中以回弹法来界定混凝土的强度,而回弹法检测中的诸多不确定性因素直接影响着检测结果,各施工实践中也显示出回弹仪所测强度与实际强度的误差较大,使其结论极易对构件混凝土强度造成误判。因此,应该正确认识回弹法测强的参考作用,规范化操作,使其在施工中具有积极的指导意义。 相似文献
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对黄骅港某港区钢筋混凝土梁、板构件强度和电通量进行测试,比较梁、板构件混凝土强度和电通量的差异性。结果表明,混凝土强度差别不大时,电通量和强度没有对应关系;强度和电通量差别较大(超过5MPa)时,高强度对应低电通量。 相似文献
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The interfacial bonding performance between seawater sand concrete and basalt fiber reinforced polymer (BFRP) bars were tested under different textile reinforced concrete (TRC) confinement layers, confinement sequences and chloride salt dry-wet cycles. The results show that TRC confinement can change the failure mode of the specimen and improve the ductility of specimens. With the increase of corrosion age, compared with the specimens with the same restrained layers in the conventional environment, the ultimate bond strength of restrained specimens before corrosion gradually decreases, and the slip value when reaching the ultimate bond strength also slightly decreases. The bond strength of the pre-restrained corroded specimens has the same development trend. Based on the bond-slip model of deformed steel bars and concrete proposed by Eligehansen for the first time in 1983—BPE model, under the control of TRC confinement and corrosion age, the relationship between the TRC confinement layer and the ultimate bond strength and slip of seawater sand concrete and BFRP steel bar is established. By fitting and predicting the ultimate bond strength, corresponding slip value, and corrosion age control of different TRC confinement layers, it is found that the confinement effect will not be significantly improved when the confinement layers exceed 4 layers. Under long-term chloride corrosion, the failure mode of the specimen may still change into splitting failure when the number of restrained layers is small. 相似文献
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基于未确知有理数的多层次评估方法研究 总被引:1,自引:0,他引:1
针对评估过程中主观数据与客观数据的统一及融合问题,提出基于未确知理论的综合评估方法。采用未确知有理数表示数据,并在建立的评估模型的基础上,采用未确知测度函数求取评估指标置信度,通过Dempster规则合成评估结果。 相似文献
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The steel tube confined concrete (STCC) column piers of marine structures have been proposed in recent years. The main advantages of STCC piers include the convenient construction process and improved core concrete strength. This research presents an experimental investigation on stainless steel tube confined concrete (SSTCC) column piers subjected to axial loading. Thirty two specimens were prepared and tested. Test variables included section shape, steel tube thickness, and concrete strength. Failure modes, axial ultimate compressive strength, strain characteristics, rigidity, confinement effect, and ductility were comprehensively investigated. Test results demonstrated that the main failure modes for circular and square specimens were concrete shear failure and steel tube fracture caused by concrete deformation, respectively. The axial compressive ultimate strength was affected by the tube thickness and concrete strength. The ultimate strength increased with the increase in the confinement factor, and the increasing ratio of the circular specimens was five times to that of square specimens. The differences in axial ultimate compressive strength of SSTCC column piers, carbon steel tube confined concrete column piers, and concrete filled steel tube column piers were also analyzed. Increasing tube thickness could increase the ductility and rigidity of the specimens. Moreover, axial ultimate compressive strengths were calculated and discussed based on different calculation models. 相似文献
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橡胶粉水泥混凝土在港航工程中应用的试验研究 总被引:5,自引:0,他引:5
就水流冲刷水工构造物带来的问题,提出了为提高水工构筑物中混凝土的力学、抗渗、抗冲磨等性能,在混凝土中掺人替代同质量砂的橡胶粉形成橡胶粉水泥混凝土。首先对不同掺量的橡胶粉水泥混凝土进行了力学性能试验,得出了抗压强度、抗折强度随掺量的变化情况;其次对不同掺量的橡胶粉水泥混凝土进行了干缩性能、抗渗性能、抗冲磨性能的试验研究。结果表明,掺入橡胶粉后的混凝土能有效减少干缩作用,同时橡胶粉的替代量为3.5%时,其抗渗性能、抗冲磨性能效果最佳。该试验研究为橡胶粉水泥混凝土在港航工程水工建筑物上的应用提供了依据。 相似文献