WATER CAPILLARY ABSORPTION OF CELLULAR CLAYED CONCRETE OBTAINED BY PROTEINIC FOAMING

Previous works have allowed us to optimise the formulation of a cellular clayey concrete obtained by proteinic foaming. The purpose is to develop insulating building materials of high environmental quality. The material was prepared from clay, CPA CEM I 52.5 cement and water that was admixed with Sodium hydroxyde so as to improve the production and the stability of the foam. The clayey material was a waste of aggregate industry and constituted in quasi totality of Kaolinite. In moist medium, building materials are sensitive to aggressions and to degradations that can be caused by the presence of water. It can be dangerous for the resistance as well as the durability of the material. In this work, parameters of hydraulic transfer were determined from the ascending vertical wetting test. This test involved specimens which were dried and sealed laterally with a plastic film, so as to yield a one dimensional water diffusion between contact planes in thermal balance with the atmosphere to 20±2 °C. Measures of mass were made and plotted versus the square root of time. The hydraulic profile has lead to estimate the capillary transport coefficient D(m²/s) using the Boltzmann transform. In the same manner, the coefficient of sorptivity S(m³m²) was determined from the volumic water content expressed versus the square root of time. The sorptivity is therefore calculated on a range of time not exceeding an hour. It can be observed that the lightened material whose density is 1g/cm³, absorbs less water than a more compact one (density 1.24g/cm³). This shows that cells created by entraining air decrease the absorption of water. Deceleration of the sorption kinetics and a reduced absorption capacity can be observed.

• INTRODUCTION

• THEORETICAL BACKGROUND

• EXPERIMENTAL TECHNIQUES

• MATERIALS

• RESULTS AND DISCUSSION

• CONCLUSIONS

• REFERENCES