Development of an Appropriate Mortar for Sustainable Rain Water Cisterns

The knowledge of the rheological properties of cement based building materials is of outstanding significance for their workability and applicability. However it usually takes extensive efforts to optimize those materials as their rheological properties may differ in a wide range depending on the physical properties of the selected source materials. By means of a case study the successful implementation of a rheologically optimized cement-based mortar for the construction of rain water cisterns is presented in this paper. The material was developed within the scope of a German-Indonesian joint project, funded by the German Federal Ministry of Education and Research (BMBF), where the storage, distribution and treatment of water has to be assured by durable concrete structures. Comprehensive rheological investigations are presented which provide the database for the optimization of the mortar with regard to its intended range of application. For the selection of the source materials, special emphasis was placed on the ready availability at low cost. The rheological properties of the fresh mortar allow an easy workability by hand while the hardened mortar shows a durable and tight appearance at the same time. The developed rehabilitation mortar can be used as a coating for walls, floors and ceilings of cisterns. The future multiplication of the project results within the region was assured by a local capacity building when the material concept was applied in practice in Indonesia for the construction of sustainable rain water cisterns in Gunung Kidul.