Among the project findings were:
-Freeze/thaw performance of the blocks did not correlate with the strength, abrasion resistance and fracture mechanics characterizations of the blocks.
- For a specific mix the less dense blocks gave lower freeze/thaw resistance.
- Freeze/thaw performance relates to the total void volumes of the block combined with the volume of pores in the 0.3 to 0.05 mm size range.
- The probability of a damaging event occurring depends on the ease with which pores in this size range can fill with water.
- Freeze/thaw resistance is not related to the weight of water absorbed in a given time in standard water absorption tests.
- The environmental conditions most likely to result in freeze/thaw damage are when the surface zone thaws and remains wet while the core remains frozen, followed by the surface of refreezing.
- Freeze/thaw tests and criteria can be used as part of a performance specification for concrete block paving.
1. TO PRODUCE BASIC MODELS OF MICRO-CLIMATES USING CURRENTLY AVAILABLE DATA ON METEOROLOGICAL CONDITIONS SO THAT APPROPRIATE FREEZE/THAW REGIMES MAY BE SPECIFIED.
2. TO INVESTIGATE THE CORRELATION BETWEEN CURRENT STANDARD FREEZE TESTS AND ACTUAL PERFORMANCE IN PRACTICE. THIS WILL DEMONSTRATE WAYS IN WHICH THESE STANDARD TESTS CAN BE MODIFIED AND SIMPLIFIED WHILE IMPROVING CORRELATION AND RELIABILITY.
3. TO DEVELOP A NEW TEST APPARATUS CAPABLE OF SUBJECTING SPECIMENS TO EXPERIMENTAL REGIMES SIMILAR TO THE ACTUAL REGIMES OBTAINED IN PRACTICE. THE ACTUAL FREEZING AND THAWING PROCESSES WILL BE SIMULATED ACCURATELY IN TIME BUT OTHER PERIODS WILL BE SHORTENED.
4. TO INVESTIGATE THE PERFORMANCE OF BLOCKS MANUFACTURED WITH NEW COMPOSITIONS REFLECTING CURRENT AND LIKELY FUTURE DEVELOPMENTS IN CONCRETE TECHNOLOGY.5. TO ADVANCE FUNDAMENTAL KNOWLEDGE OF THE PROCESSES WHEREBY FREEZE/THAW DAMAGE OCCURS IN CONCRETE, PARTICULARLY CONCRETE PRODUCED USING THE SEMI-DRY PROCESS.
THE RESULTS WILL ENABLE ECONOMIC BLOCK PRODUCTS TO BE PRODUCED OF A QUALITY ADEQUATE TO DEAL WITH LIKELY CLIMATIC CONDITIONS IN SERVICE. THIS RESEARCH COULD FORM THE BASIS FOR A EUROPEAN STANDARD FOR BLOCKS, ENCOURAGING COMPETITION AND UNIFORMITY OF PRODUCT. THIS WILL GIVE FURTHER ECONOMIES.
Funding SchemeCSC - Cost-sharing contracts
LE1 1FB Leicester