The laterite may form cracks due to shrinkage for dehydration. These cracks not only reduce the overall strength

but also provide infiltration channel for rainwater

which intensifies the weakening of its bearing capacity. Therefore

how to inhibit laterite shrinkage is a key problem for engineering applications. The nano-silica particles are extremely fine in size and belong to the nano category. It is proposed to fully utilize the size advantage of nano-silica

so that nano-silica particles can enter the laterite aggregates and resist the shrinkage behavior of laterite caused by dehydration. Therefore

different dry mixing ratios (i.e. nano-silica: laterite = 0: 100

2: 100

3.5: 100

5: 100

and 6.5: 100) were programmed

and nano-silica was mixed with laterite for compaction (dry density is 1.44 g/cm3 and 1.46 g/cm3 respectively). Shrinkage characteristics and pore distribution of compacted laterite-nano-silica mixture were compared. It was found that nano-silica could inhibit the shrinkage of laterite

and the shrinkage limit was also increased by the mixing ratio rising. Besides

plenty of nano-silica particles were found in the pores while the mixing ratio was greater than 5% by means of apparent morphology images. Meanwhile

the pore distribution curve also showed that the pores with diameter at 0.03 ?m reduced significantly

which indicated that nano-silica mainly filled the pores with diameter greater than 0.03 ?m. Adding nano-silica into laterite is a physical method to improve the shrinkage properties

which is different from the chemical methods such as lime treatment and has potential advantages to environmental protection.