Defelsko now presents the new PosiTector CMM IS Concrete Hygrometer - an in-situ probe for measuring relative humidity and temperature on concrete floors. Acquires and displays measurement data consistent with ASTM F2170 for determining relative humidity on concrete floors using standard test methods using in-situ probes. The PosiTector CMM IS Concrete Moisture Meter Probe is designed to wirelessly connect the PosiTector App (iOS/Android) with the PosiTector DPM Advanced Model via Bluetooth. This article compares the different methods used to measure the relative humidity of concrete in floor slabs, details the innovative concrete moisture measurement system offered by DeFelsko, and explains how to perform the test. Due to the limited translation ability, please forgive me for the incomprehension.
background
Concrete is a composite material made of fine and coarse aggregates bonded together with cement (calcium oxide). When mixed with water, cement powder undergoes a chemical reaction that binds aggregated materials together into a durable stone-like building material. However, after hardening (curing), most of the water remains as moisture in the porous concrete structure. This moisture is slowly drained from the concrete over the next few months until it eventually equals the ambient moisture content.
Measuring Concrete Moisture
Before applying protective coatings or other flooring materials to concrete slabs, it is necessary to ensure that the moisture content within the concrete is reduced to acceptable levels. Otherwise, moisture can accumulate under the coating or floor, causing discoloration, cupping, warping, blistering, bond failure and/or mold growth. There are various methods used for concrete moisture measurement. Three common methods use nondestructive electronic meters, anhydrous calcium chloride, or in situ relative humidity (RH) probes.
A non-destructive electronic meter measures the electrical impedance of concrete, which is related to concrete moisture. Due to their design, these gauges may be affected by other slab conditions, such as changes in concrete composition and the presence of reinforcement materials. ASTM recommends that these concrete Moisture Meters be used as comparators, not for determining quantitative moisture content.
The Anhydrous Calcium Chloride Test involves measuring the increase in body weight salt as it collects moisture from an encapsulated area on the concrete surface. However, major doubts about the test's accuracy have emerged:
测量混凝土的新行业标准是ASTM F2170标准测试方法中描述的原位混凝土相对湿度测试。它涉及在混凝土中钻一个孔，并使用电子相对湿度探头直接测量板坯中的水分。
与其他方法相比，原位RH测试具有许多优点：
DeFelsko的解决方案
所述PosiTector CMM IS原位混凝土水分测定仪是测量ASTM F2170混凝土相对湿度的简单，耐用和准确的方法。每个NIST可追踪探头都包括校准检查盐和腔室，用于调节和储存。探头具有自动配对蓝牙低功耗（BLE）无线技术，可将具体水分测量值传输至运行免费PosiTector App（iOS和Android兼容）或PosiTector Advanced仪器 （序列号784,000及更高版本）的智能手机。
每个PosiTector CMM IS探头使用单个纽扣电池碱性电池运行长达三周，并采用创新的组合套管和探头设计，提供与单独套管相同的功能，无需消耗费用或麻烦。还包括一个可重复使用的亮黄色盖子，用于将探头密封在测试孔内。
免费的PosiTector App允许用户ASTM F2170轻松捕获和报告探针数据。使用兼容的智能手机或平板电脑，将每个探头覆盖在平面布置图上，并ASTM F2170的要求添加元数据和注释。测试完成后，快速打印专业PDF报告，其中包括标准所需的所有数据。
从三种PosiTector CMM IS套件配置中选择 - Basic，Complete和Pro。
该临套件包括从所有项目的完整试剂盒除了一个PosiTector DPM3高级计，用于测量环境温度和湿度所钻的孔的上方。它可以无线接收和记录现场湿度和温度测量值，并与环境测量值一起显示。所述PosiTector DPM3还包括表面温度传感器的优良之选混凝土温度测量。
PosiTector CMM IS测量过程
（ASTM F2170）
步骤1：确定所需探针的数量。
ASTM F2170在前1,000平方英尺（100平方米）内需要3个探头，另外每1000平方英尺（100平方米）需要另一个探头。需要在每个外墙3英尺（1米）范围内进行一次测试。
使用PosiTector应用程序通过智能手机拍摄测试区域布局图的照片来映射和覆盖探头位置。在测试开始之前，确保板坯和环境条件在使用条件下至少48小时。
第2步：验证探头校准。
PosiTector CMM IS探头包括可溯源至NIST的长形校准证书。ASTM F2170要求每个探头在使用一年内进行校准。ASTM F2170还要求在使用饱和盐溶液30天内验证探针校准。为了便于验证，每个PosiTector CMM IS探头都可以方便地预先包装在校准室中，并配有饱和盐溶液。只需打开探头并将其插回腔室，确保探头读数与腔室上的标签一致。有关详细信息，请参阅说明手册中的“准确性验证”部分。
第3步：钻测试孔。
使用锤钻和¾“钻头，钻至所需深度 - 如果仅从一侧（即板坯上）干燥，则为板坯厚度的40％，如果是干燥，则为板坯厚度的20％两面（即悬挂板）。清除孔中的任何碎屑，并使用PosiTector App记录钻孔的时间。
第4步：插入探头。
Place the PosiTector CMM IS probe into the hole (sensor end first) and gently push it to the bottom. Seal the probe in the well using the provided yellow cap. Note when the probe is inserted using the PosiTector App.
Step 5: Collect in situ readings.
The probe starts measuring immediately and readings can be displayed at any time using the PosiTector App or the PosiTector Advanced meter body. However, ASTM F2170 requires waiting 24 hours to ensure that conditions in the well have equilibrated before recording measurements. After a period of time, using the PosiTector App or PosiTector Advanced meter body eliminates the need to record site temperature and humidity as well as time and date, without opening holes or removing probes.
Step 6: Take out the probe.
After the RH test is complete, remove the reusable PosiTector CMM IS probe from the hole using the extraction tool provided. Fill the hole with a suitable patch. ASTM F2170 also requires the measurement of ambient temperature and humidity above the hole. If using the PosiTector App, place a CMM IS probe next to the hole and record the ambient conditions. If using a PosiTector DPM Advanced gauge, environmental conditions are automatically recorded and measured on-site.
Step 7: Report test results.
With all probe data required by ASTM F2170 collected, the test is now complete. Use the PosiSoft software to download stored readings from the PosiTector Advanced meter body, or press the "Report" button in the PosiTector App to view a PDF inspection report. The report contains all the information required by ASTM F2170 and can be emailed or saved.
in conclusion
The innovative PosiTector CMM IS makes the concrete moisture measurement and reporting process faster, easier and more accurate. The certified reusable probe is a satisfactory solution for measuring in-situ concrete RH according to ASTM F2170.
