J.J. BROOKS and J.P. FORTH University of Leeds
Test data are reported for 160-day creep and shrinkage of 2-brick wide x 13-course high single leaf clay brickwork constructed from six types of unit having strengths ranging from 30 – 120N/mm2 and a 1: 0.5 :4.5 ordinary Portland cement:lime:sand mortar. The curing period was 14d under polythene and I4d exposure to air at 21 °C and 65% R.H. Although there are general trends of elastic strains and creep with unit strength of an inverse nature, there is high variability for low unit strengths. An improved relationship for elastic strain and early creep is in terms of unit modulus of elasticity. However, that relationship is poor for longer term creep of walls built from units exhibiting high unbonded unit creep. Measured and extrapolated ultimate creep coefficients exceed the design values in some cases. Existing empirical relationships overestimate modulus of elasticity for walls built from low strength units. Low strength unit walls generally tend to show moisture expansion, while high strength unit walls undergo shrinkage, but this is not always the case. Moisture expansion of walls can exceed the moisture expansion of unbonded units.