Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Hydric behavior of earth materials and the effects of their stabilization with cement or lime: Study on repair mortars for historical rammed earth structuresPublication . Gomes, Maria; Diaz Gonçalves, Teresa; Faria, PaulinaEarthen building materials bear interesting environmental advantages and are the most appropriate to conserve historical earth constructions. To improve mechanical properties, these materials are often stabilized with cement or lime, but the impact of the stabilizers on the water transport properties, which are also critical, has been very rarely evaluated. The researchers have tested four earth-based repair mortars applied on three distinct and representative rammed earth surfaces. Three mortars are based on earth collected from rammed earth buildings in south of Portugal and the fourth mortar is based on a commercial clayish earth. The main objective of the work was over the commercial earth mortar, applied stabilized and not stabilized on the three rammed earth surfaces to repair, to assess the influence of the stabilizers. The other three earth mortars (not stabilized) were applied on each type of rammed earth, representing the repair only made with local materials. The four unstabilized earth materials depicted nonlinear dependence on t1/2 during capillary suction. This behavior was probably caused by clay swelling. Stabilization with any of the four tested binders enabled the linear dependence of t1/2 expected from Washburn's equation, probably because the swelling did not take place in this case. However, the stabilizers also significantly increased the capillary suction and the capillary porosity of the materials. This means that, in addition to increasing the carbon footprint, stabilizers, like cement and lime, have functional disadvantages that discourage their use in repair mortars for raw earth construction.
- Rammed earth walls repair by earth-based mortars: The adequacy to assess effectivenessPublication . Gomes, Maria; Faria, Paulina; Diaz Gonçalves, TeresaRepairs in rammed earth walls are often necessary mainly because of degradation occurring during the life time of a building with continuous environmental exposure. The defects that arise in the walls are generally associated with loss of its thickness, on the surface or in greater depth. They must be repaired with a mortar technically efficient and compatible with the rammed earth, to ensure protection and, as possible, long-term durability. The present study describes and discusses the adequacy of earth-based mortars to repair unstabilized rammed earth walls and the behaviour of the systems rammed walls-earth repair mortars when subjected to accelerated aging tests by wetting-drying cycles. Even under aggressive capillarity tests, the results observed corroborate that unstabilized earth repair mortars behave better in comparison to similar mortars with additions of low amounts of different inorganic binders.