Polymer impregnanted concrete polymerization

The technology of concrete soaking with monomeric substance and subsequent m situ" polymerization is relatively new. According to Worn [171], it was initiated by Steinberg in 1968. Beside of the polymer impregnated concretes, there are also the polymer concretes (resin concretes) without cement and the polymer-eement concretes in the latter case cement is mixed with monomer and water to produce the concrete mixture . This question will be discussed in Chap. 10. 

This chapter will be devoted to the consideration of nascent research undertakings, possible new materials, and as yet unanswered research questions. First, an effort will be made to codify and classify composite materials and polyblends with respect to topological considerations. We will examine what other ways may possibly exist to make new combinations of two types of polymeric molecules. How many ways exist to mix two kinds of polymer molecules What relationships can be developed among such diverse materials as particulate and fiber-reinforced plastics, polymer-impregnated concrete, and foams, paint films, etc. ... 

Polymer Impregnated Concrete (PIC) obtained with hardened ordinary concretes, which are dried and then permeated with monomers of sufficient viscosity by vacuum or monomer displacement and pressure. Then, in-situ polymerization of the monomer is carried on by radiation, heating or chemical initiation. As an effect, a large part of the voids and pores is filled with polymer, which forms a continuous reinforcing network. 

Polymerization of monomer-impregnated concrete was initially carried out with 60Co gamma radiation. A principal advantage of using radiation is that free radical chain reactions can be induced at ambient temperature. This limits vaporization loss and may produce a better concrete-polymer bond. The disadvantages are the dose requirements and the relatively high initial investment required for the radiation source and facility. 

Very hard coatings may be obtained by irradiation of polymerized varnishes on wood or metals. Irradiation of wood impregnated with a monomer leads to waterproof products of high stability and hardness. Similarly to these wood-polymer combinations, concrete-polymer combinations can also be produced that exhibit high resistivity in water, particularly in seawater. 

U. Dilthey, M. Schleser Composite Improvement of Textile Reinforced Concrete by Polymeric Impregnation of the Textiles. In Proceedings ISPIC International Symposium Polymers in Concrete 2006, 2th-4th April 2006, University of Minho Guimaraes, Portugal, p. 185-192(2006)... 

In polymer-impregnated cementitious materials the prehardened cement paste, mortar or concrete is impregnated with a low molecular weight, low-viscosity polymer precursor, which, after having filled the existing pore space, is brought to polymerization. The resultant material is a hardened cementitious body, in which the original pores are filled with the polymer. 

Yu Fei-xiong and Huang Yiun-yuan, Mechanical properties of PIC impregnated and polymerized under high pressure. Polymer Concrete, Uses, Materials and Properties, SP-89 ACI Committee 548, 1983, pp. 161-176. 

PIC is a precast and cured portland cement concrete that has been impregnated with a monomer that is subsequently polymerized in situ. This type of cement composite is the most developed of polymer-concrete products. PCC, on the other hand, is a modified concrete in which a part (10%-15% by weight) of the cement binder is replaced by a synthetic organic polymer. It is produced by incorporating a monomer, prepolymer-monomer mixture, or a dispersed polymer (latex) into a cement-concrete mix. To effect the polymerization of the monomer or prepolymer-monomer, a catalyst (initiator) is added to the mixture. The process technology used is very similar to that of conventional concrete. So, unlike PIC which has to be used as a precast structure, PCC can be cast-in-place in field applications. PC can be described as a composite that contains polymer as a binder instead of the conventional portland cement. 

Polymers may be incorporated basically in three ways (a) by adding a polymerizable monomer to a concrete or mortar mix, and then curing both concrete and polymer (b) by adding a latex or an aqueous solution of a polymer to a mortar, or concrete mix, and then curing the composition in the presence of the polymer and (c) by impregnating a cured mortar or concrete with a monomer, and then polymerizing the monomer using thermal or radiation catalysis. 

---