An insight to cleaning terrazzo surface
One problem that occurs frequently with new terrazzo is a cloudy or milky surface appearance. Terrazzo makers often meet with little success in their efforts to eliminate clouding because they most often attempt to correct the situation with repeat applications of the same materials and procedures that permitted the original difficulty. Such measures would be successful only if the original problem was created by inefficient workmanship, which is seldom found to be true. The situation is created by the basic chemistry of the setting of cement, and is compounded by failure of cleaning chemicals and processes used in trying to remove and eliminate the residue of the cement chemistry from the surface of the floor.
To explain more fully, the components of Portland Cement powder change their physical and chemical form when combined with water. One of the end products of this combination is Calcium Hydroxide, which results at a rate of about six-tenths of a pound for each pound of cement used. This Calcium Hydroxide is better known as lime. Most of this converted lime is used to bind the terrazzo together, but there is a certain amount of free lime that remains on the surface and in the pores of the terrazzo products after the final grinding.
Water, by itself, is capable of dissolving only about one-sixteenth of the free lime. The remainder must be disposed of by other means. Clear water flushing and scrubbing will not be totally effective in removing all of the free lime from the pores of a new terrazzo surface. A detergent action is needed. It is an established fact that terrazzo cleaners should be neither acid or highly alkaline. Rather, they should be neutral. Being neutral however, is not the only important factor; being effective is most critical.
To digress further, a soap is a combination of fatty acid oils and alkaline materials. Detergents, on the other hand, are synthetic products that act in the same general manner as soap, but are most often more effective in their performance. Some of the most popular chemicals used for cleaning terrazzo are soap rather than a detergent. The makers of these popular soaps have cleverly made their product neutral, but have balanced the alkaline component in such a way that it does not completely react to all of the fatty oils. This is much like the TV ad in which the daughter asks "Mom, where is the bath oil?" and the mother replies that it is in the soap. When these soaps are used on terrazzo, they leave a thin film of this unreacted fatty oil, which will shine when the terrazzo is buffed after it is dry.
The problem of clouding is created when this film entraps and reacts with the residue of free lime on the terrazzo surface, causing insoluble calcium scum. Repeating the cleaning procedures with the same materials only adds to the condition. Applying a primer, sealer or wax on top will lock in the scum under a transparent shield. This makes everything worse, for the sealing film must then be removed to expose the source of the problem for corrective treatment.
This situation can be prevented or minimized by thorough cleansing of the terrazzo surface with proper chemicals before any sealer of other film or scum forming surface treatments are used. Non-ionic neutral detergents will thoroughly clean terrazzo without reacting to or combining with any free lime deposit or residue. The preceding relates to preparation of terrazzo for delivery, but long range maintenance programs with this type of film-forming soap also have limitations. The oily film never really hardens, so it will continue to trap dust and dirt.
The cumulative effect of continuing use of such a material will cause even the most immaculate terrazzo to become dull and lifeless. Detergents leave no oily film or residue to accumulate dirt. Your material suppliers should be able to help you distinguish between soap and detergents.
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Summary:
One problem that occurs frequently with new terrazzo is a cloudy or milky surface appearance. Terrazzo makers often meet with little success in their efforts to eliminate clouding because they most often attempt to correct the situation with repeat applications of the same materials and procedures that permitted the original difficulty.