Igice cyo gutuza cyamazi (sima itunganijwe neza ya kaburimbo), izwi kandi nkicyuma kitagira amazi cyangwa igicanwa n’amazi, nigice cyingenzi cyubwubatsi bwumuhanda. Iherereye hagati ya subgrade yuzuza igipande cya pavement, intego nyamukuru ni ukurinda kwimuka hejuru y’amazi yo mu butaka n’ubushuhe, kugirango habeho ituze ryuzuzwa rya subgrade hamwe nimbaraga imwe yo gutwara pavement. Ibikoresho nyamukuru bikoreshwa ni ibumba, umucanga, sili, sima, icyuma nibindi. Ibi bikoresho birashobora gukoreshwa byonyine cyangwa bigahuzwa hamwe ukurikije imiterere yabyo kugirango bigere kumazi meza no guhuza. Uburyo bwo kubaka nuburyo bwa reberi yoguhuza uburyo, uburyo bwa pave nuburyo bwo gutera. Ubu buryo bwubwubatsi bufite umwihariko wabwo, bugomba gutoranywa ukurikije imiterere yihariye yumushinga. Igice cyamazi cyamazi ni umuhuza wingenzi kugirango umutekano uhagaze neza. Nubwo ari urwego rwimiterere rutitaweho cyane nabantu, uruhare rwarwo ningirakamaro.