Conclusions

Engineering properties of commercial patch repair mortars

From the study conducted the following conclusions were drawn:

The cementitious mortars, CM1, CM2 and CM3, yielded the highest strength gains in both compression and tension over the 28 day period.

The cementitious mortars as expected, due to their high strength, also had the highest elastic modulus values of the 28 day period.

The PM and FM products experienced the least ammount of shrinkage, whereas the cementitious mortars which were "shrinkage compensated" experienced the highest ammount of shrinkage.

A relationship between the crack age and area was noted, whereby the earlier the crack age the larger the crack area.

The crack prediction model proved to be an accurate tool in predicting the crack age of a restrained material using the Ring test.

Thus when strength is the key factor, it was recommended that the CM3 be used due to its high strength and moderate degree of shrinkage.

When tensile cracking is an important attribute, it was recommended that the FM or PM be used due to its low shrinkage.

References

ASTM C 1581-04:1. (2004). Standard Test for Determining Age at Cracking and Induced Tensile Stress Characteristics of Concrete and mortar under Restrained Shrinkage.
Beushausen, H., & Alexander, M. (2009). Concrete Repair. Fulton's Concrete Technology, 393-412.
Morgan, D. R. (1996). Compatibility of concrete repair materials and systems. Constuction and building materials Vol.10 No. 1, 57-67.
SANS 5863. (2006). Concrete tests: Compressive strength of hardened concrete. South African
National standards.
SANS 6253. (2006). Concrete tests: Tensile splitting strength of concrete. Pretoria.