Corrosion of steel reinforcement in concrete is caused by an electrochemical process. Generally, a decrease in the electrical resistivity of concrete increases the likelihood of steel corrosion. In practical measurements of concrete resistivity, it is essential to ensure good electrical contact between the test electrodes and the concrete surface. The LD-4000 Concrete Resistivity Tester's sponge probe sensor is designed to ensure optimal electrical contact. It includes a standard test block to guarantee measurement reliability, a reading hold function, and an aluminum alloy carrying case for easy portability. 
Testing method: Uses a Wenner array sensor (50mm spacing) to measure concrete resistivity 
Testing parameter: Concrete resistivity 
Testing objects: Fresh concrete, wet concrete.