Shrinkage during wetting of fine-pored materials: Does this accord with the principle of effective stress?

According to the principle of effective stress, unsaturated porous materials will shrink if they become dryer and swell if they become wetter. An interesting situation arises when such a material approaches a completely dry state. If the negative pore water pressure that has caused the material to shrink, disappears because there is insufficient water to sustain it, does the material expand? If the material is then re-wetted sufficiently for the negative pore water pressure to be re-established, is the material then re-compressed? The paper describes a set of experiments designed to establish what happens and reports the result.