Modified roman cement

Abstract

The purpose of this research is to equip the roman cement with properties exceeding the properties of the known analogies. Roman cement’s compositions modified by chemical and mineral additives have been developed and proposed. The mode of calcinations of carbonate and clay raw material with high MgO has been optimized. As a result, the durability of roman cement from 15 to 22 MPa has been received. Mineral additives like slag, zeolite breed and clay dust were chosen and used that rose the durability from 22 to 28 MPa. Plasticizers and hardening accelerators were chosen and used that allowed rising the durability up to 35 MPa relatively. A combination of complex additives have been proposed. To optimize the mode of calcinations and to define a combination of complex additives the method of mathematical planning was used. The dependence of binder’s strength from the temperature, durability of calcinations, saturation rate, type and consistence of modified additives has been acquired. Modified roman cement has the advantages if compared with known analogies and has the following features: strength 35MPa, normal consistency 30%, setting time is not earlier than 35 minutes, the end is not late than 420 minutes, softening rate is 0.98. Modified roman cement can be successfully used to produce dry building mixtures (mortar’s strength 5,10, 15 MPA), low strength mortars (strength 5,7.5 MPa) and concret (strength 10, 15, 20, 25 MPa) and other building materials. Structure of carbonate raw material and clay for the production of roman cement is recommended.