表贴式传感器监测水泥凝结过程

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中图分类号： TU317+ .8 文献标志码：A

Abstract：To meet in-situ monitoring requirementsofconcreteseting timeinactualengineering，asurface mountedsensor basedon ultrasonic test monitoring system was prepared to continuously monitor seting processes of cement samples with different mix proportions for 24h ，and waveform analysis methods in time domain and frequency domain of monitored ultrasonic signals，as wellas parameters of maximum voltage amplitude and energy were selected.Relationship between theultrasonic wave parameters and initial seting time nodes was analyzed based on testresultsof Vicat instrumentand penetration resistance instrument.Theresults show that the sensor can monitor drastic changes in the maximum voltage amplitudeofultrasonicsignalsatinitialsettngtime nodesofcementpaste，sothat initialsettingtime nodesof thecement pastecanbedetermined immediately.According to the maximum voltage amplitude changeof the sensor at different ultrasonic signal excitation frequencies，the initial settng timeof thesensor can beaccurately determined，and monitoring effectiveness ofthe sensor on initial setting time nodes ofcementpaste isverified.Whenthe excitation frequency is 0.20MHz ， the monitoring effctivenessof the sensor on initial setting time nodes of cement paste is the best.The maximum voltage amplitude mutation timeof ultrasonic signals ofcement pastewith different water to cement massratios monitored using the sensorisdelayed with the increaseof water tocement mass ratio，which is basicallyconsistent with the initialseting timeof cement paste measured using Vicat instrument.The maximum voltage amplitude mutation time of ultrasonic signals ofconcretewiththestrength gradeof C3O monitored usingthesensorisbasicallyconsistent with the initialsetting timeof theconcretemeasured using thepenetrationresistance instrument.Itisverified thatthe sensoris feasible for determining initial seting timeofcement paste with diferentwater tocement massratios andis alsoapplicable to concrete.

Keywords： ultrasonic inspection；in-situ monitoring；surface mounted sensor;cement； initial seting time

水泥凝结异常导致混凝土结构性能劣化、施工难度增加以及工程进度延误，这种异常可能由水泥的化学成分、细度、颗粒形貌、养护条件、外加剂的使用等多种因素引起[1]。（剩余8345字）