Device name：Upgraded Horizontal Shrinkage Expansion Instrument
Model：YC-HSP540D
Origin：Beijing
Purpose：A special instrument for measuring the change of length (volume) of concrete specimens during hardening under certain environmental conditions.
型號：YC-HSP540D
用途：用于測量混凝土試件在一定環境條件下，硬化過程中長度（體積）發生變化的專用儀器，可為建筑科學研究院所、門、設計和施工單位對砊的特性進行研究、教育、質量控制和檢測提供可靠依據。
執行標準：
GB/T50082-2009《普通混凝土長期性能和耐久性能試驗方法標準》
現有臥式混凝土收縮膨脹儀存在如下不足：
（1）標準中校準桿材質建議選擇硬鋼或石英玻璃材質制作，但目前市場上的校準桿基本上都為不銹鋼材質，不銹鋼校準桿的線膨脹系數很大，易因溫度波動影響造成誤差。
（2）千分表精度差，即使選用業內較好的電子千分表也有±3um的測量誤差，一般的千分表誤差在±5um以上，這對于混凝土試件后期收縮量本來就很小而言，會造成很大的誤差。
（3）試驗過程人工讀數記錄，易因人為筆誤或在數據抄寫過程中失誤造成錯誤。
并且，由于在整個試驗周期中，同一個試件要測量十幾次，上述3種誤差因素會被不斷放大，很有可能出現前后試驗結果相互矛盾的現象，且無法找到問題根源。
The shortcomings of available horizontal concrete shrinkage expansion meter:
(1) Hard steel or quartz glass is recommended for the calibration rod material in the standard, but the available calibration rod in the market is mostly made of stainless steel. Its linear expansion coefficient is too high, which is easy to cause errors due to the influence of temperature fluctuation.
(2) The accuracy of the micrometer is poor, even if the best electronic micrometer is used, because its measurement error is more than 3um. Generally, the error of the micrometer is more than 5um, which will cause a great error for the shrinkage of concrete specimens in the later period.
(3) Manual reading records during the test process are prone to errors, which is caused by human errors or errors in data transcription.
Moreover, the same specimen needs to be measured more than a dozen times in the whole test cycle. The above error factors will be enlarged continuously, and it is likely that there will be conflicting phenomena between early and later results. We can’t find the root cause of the problem.
