The present invention relates to fiber cement products comprising an inner core material, which inner core material is covered by at least one outer surface layer, characterized in that:said inner core material has a density of between about 0.4 and about 0.9 g/cm.sup.3 inclusive, and at least comprises cement and between 1 wt % and 70 wt % (with respect to the total dry weight of said inner core material) of a lightweight filler, andsaid at least one outer surface layer has a density of between about 0.9 and about 1.4 g/cm.sup.3 inclusive, and at least comprises fibers and cement.

The present invention relates to fiber cement products comprising an inner core material, which inner core material is covered by at least one outer surface layer, characterized in that:said inner core material has a density of between about 0.4 and about 0.9 g/cm.sup.3 inclusive, and at least comprises cement and between 1 wt % and 70 wt % (with respect to the total dry weight of said inner core material) of a lightweight filler, andsaid at least one outer surface layer has a density of between about 0.9 and about 1.4 g/cm.sup.3 inclusive, and at least comprises fibers and cement.

A novel method for forming unique carbon aerogels may be provided. The method may include drying a precursor composition including an organic molecule. The method may include generating a porous aerogel by graphitizing the organic molecule (such as a self-assembling protein, a sugar, etc.). The organic molecule may be a phase transition material, where the heating leads to formation of a viscous melt pool, and further heating of which releases gases such as CO.sub.2, NH.sub.3, H.sub.2S, SO.sub.2, etc. Due to the use of such a phase transition material, generating the porous aerogel may be accomplished without a separate gas generant. The graphitizing may include heating the precursor composition to a first temperature of 300-1200 C. at a first heating rate. The graphitizing may include holding the precursor composition at the first temperature for a holding time no more than 48 hours.

A novel method for forming unique carbon aerogels may be provided. The method may include drying a precursor composition including an organic molecule. The method may include generating a porous aerogel by graphitizing the organic molecule (such as a self-assembling protein, a sugar, etc.). The organic molecule may be a phase transition material, where the heating leads to formation of a viscous melt pool, and further heating of which releases gases such as CO.sub.2, NH.sub.3, H.sub.2S, SO.sub.2, etc. Due to the use of such a phase transition material, generating the porous aerogel may be accomplished without a separate gas generant. The graphitizing may include heating the precursor composition to a first temperature of 300-1200 C. at a first heating rate. The graphitizing may include holding the precursor composition at the first temperature for a holding time no more than 48 hours.