THE EFFECT OF NONIONIC SURFACTANTS ON THE STATE OF WATER IN CEMENT SYSTEMS (BY NMR RELAXATION DATA) - 2 - A MODEL OF THE PORE-SPACE

The state of water in cement compositions containing polypropylene gly col (PPG) and hexanol in the course of their hardening for a time up t o 28 days was studied by the NMR relaxation technique. A model of the porous structure formed in the process of cement hardening, which take s into account the distribution of water in pores of cement stone in t he presence of additives, is proposed. It is shown that, in the absenc e of additives, the number of large pores in cement stone (being the l argest defects, these pores determine the strength of cement stone) no ticeably decreases with increasing the hardening time from 7 to 28 day s. PPG and hexanol have different effects on the structure of cement s tone in the process of its hardening. According to NMR data, the prese nce of PPG results in the formation of large-size pores (19-35 mu m), whose-number increases with increasing hardening time and the additive concentration: In the presence of hexanol (1%), the content of macrop ores in cement stone is close to their content in the reference sample ; however, in the presence of hexanol, this level of macropore content is attained in shorter hardening times (about 7 days).