1993 Volume 42 Issue 476 Pages 581-587
Recently, a relatively high molecular weight methacrylate monomer (HMWM monomer) has been developed. Since the monomer hardly evaporates under an ambient condition, it is possible to apply a thermal polymerization process under the atmospheric pressure in the production of polymer impregnated concrete or mortar (PIC). Furthermore, since it polymerizes at room temperature, it is possible to eliminate the thermal polymerization process.
This paper describes the compressive strength of PIC using the mixtures of HMWM monomer and multifunctional acrylic monomers. The factors in the experiments were as follows: the number of functional groups of the multifunctional acrylic monomers and their contents, the water-cement ratio of base mortars, polymerization temperature and the polymerization time of PIC polymerized at room temperature (20°C). Compressive strength tests were made on 16×30mm cylindrical specimens. The water-cement ratio of the base mortars for PIC was varied from 30 to 60%, and their sand-cement weight ratio was 1.0. PIC using HMWM monomer or the mixtures of HMWM monomer and the multifunctional acrylic monomers were prepared as follows: (1) The base mortars were dried at 110°C for 48 hours, (2) evacuated at 8.0kPa for 1 hour, (3) impregnated with the monomers, (4) pressurized at 0.20MPa for 30 to 40 minutes, and (5) subjected to thermal polymerization at 70°C for 12 hours or storage at room temperature for 14 and 28 days. The principal conclusions obtained from the test results are summarized as follows:
(1) The compressive strength of the base mortars is extremely improved by using mixed HMWM monomers, even though the compressive strength of PIC using mixed HMWM monomers is lower than that of PIC using MMA monomer.
(2) When the number of functional groups of the multifunctional acrylic monomers increases 2 to 6, the compressive strength of PIC increases. In the range of the content of the multifunctional acrylic monomers 10 to 30%, the highest compressive strength of PIC is obtained when the content is 20%.
(3) The compressive strength of PIC increases with the glass transition temperature of polymers.
(4) The water-cement ratio of the base mortars influences the compressive strength of PIC, and the smaller the water-cement ratio becomes, the higher the compressive strength of PIC does.
(5) In the use of a mixed HMWM monomer with a number of functional groups of multifunctional acrylic monomer of 6 and a multifunctional acrylic monomer content of 20%, the compressive strength of PIC polymerized at room temperature for 14 days is nearly equal to that of PIC polymerized at 70°C for 12 hours.
