| Description |
The moisture content in civil engineering materials determines many of the structural properties of the material such as strength and durability. In geotechnical engineering, the moisture content of soil deposits determines their susceptibility to landslides and settling. In structural engineering, the moisture content in concrete, typically measured in terms of the water-to-cement (w/cm) weight ratio, determines its compressive strength as well as other hardened properties such as permeability and shrinkage. The moisture contents of sand and concrete composites were measured using a handheld microwave moisture meter developed for the purpose of moisture measurements in concrete. The results in concrete obtained from the meter were compared to the results obtained from the standard method of determining moisture content in concrete. In sand, the meter was able to detect the change in moisture content with a linear fit R 2 of 0.962 and 0.945 for the twotypes of sands tested. As for concrete, the linear fit R 2 was as low as 0.0034.The p-values obtained on concrete testing were less than the specified confidence level of 0.05, rejecting the hypothesis that the meter's average output is equal to the average actual w/cm tested. The output w/cm obtained from the meter was compared to moisture content and calculated w/cm from the AASHTO standard method. The linear fit through the data obtained from the test had an R 2 value of 0.62 or higher and a p-value of 0.91, making this methodthe preferred option when wanting accurate in-situ measurements. |
