Ƙarfin launin toka da aka narkar da shi yana da ruwa mai kyau, kuma ƙarar ƙararsa da raguwar layinsa ƙanƙanta ne, kuma ƙarancin hankali ƙarami ne. Don haka, ana maraba da kyakkyawan ikon yin simintin ƙarfe ta hanyar simintin harsashi. Haka kuma, simintin gyare-gyaren harsashi mai launin toka suna da good shock absorption, wanda kusan sau 10 ya fi na simintin ƙarfe na simintin gyaran kafa.