1H NMR monitoring of dynamic microstructure evolution of HACP during adsorption of different fluids

Abstract

In order to develop functional concrete suitable for sponge city construction, a high adsorbent cement paste (HACP) was prepared. The capillary water absorption performance of the HACP reached 70 kg/m2, and the compressive strength reached more than 30 MPa. Taking advantage of the relatively large proportion of capillary pores in HACP and combining the test results of MIP and BET, a non-linear calibration method for low-field NMR was proposed. The conversion of calibration results of different fluids such as diesel oil (DO), soybean oil (SO), and engine oil (EO) were realized. Through 1H NMR real-time monitoring of the adsorption process of water, DO, SO and EO in cement slurry, it was found that HACP is mainly capillary adsorption, and the adsorption rate of the fluid is negatively correlated with the viscosity. In addition, it was also found that fluid transmission is not always from small pores to large pores, but also from gel pores to interlayer pores. Finally, a dynamic microstructure evolution model of HACP was proposed.