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The use of internal curing is a highly effective means of mitigating autogenous shrinkage in cement mortars (w/s=0.35, 8 % silica fume). Two different sources of internal water supply are compared: 1) replacement of a portion of the sand by saturated low-density fine aggregate and 2) the addition of superabsorbent polymer particles (SAP). At equal water addition rates, the SAP system is seen to be more efficient in reducing autogenous shrinkage at later ages, most likely due to a more homogeneous distribution of the extra curing water within the three-dimensional mortar microstructure. A comparison of the water distribution in the different systems, based on computer modeling and direct observation of two-dimensional cross sections, is given.