Evaluation of water behavior between aggregate and cement paste matrix by neutron radiography

Abstract

The purpose of this study is to evaluate a water-supplied area from the saturated lightweight aggregate in high strength concrete. For this objective, phenomena of water transfer between cement paste, whose water to cement ratio is 0.25, and aggregates is visualized by neutron radiography technique. The parameter of this test was the type of aggregates, namely, saturated lightweight aggregate, air dried lightweight aggregate, and ordinary sandstone. Additionally the steel is also tested for understanding the 'wall-effect'. Experimental results show that water supply from saturated lightweight aggregate continued upto more than 14 days, and the water supplied area of cement paste was ranged within 4mm from the aggregate surface, and air dried lightweight aggregate suck the water from cement paste upto 12 hours and that water was released after 24 hours. Reduction of water content in cement paste, which was seen in both the test with steel and ordinary sandstone, was ranged within 1.2 mm from the surface.