Ferrocement is a type of thin reinforced concrete construction, mostly used for aesthetical purpose, but not always. The advantage of this technology is that it is very flexible, and can be used to create any shape and form of structure. The cement mortar mix is reinforced with layers of steel wire mesh (which is also known as chicken wire mesh). The mesh is used to act as tensile stress absorber, as well as to provide ductility and stability to the ferrocement structure. The cement mortar mix is mainly providing the mass to the structure. The ferrocement also exhibits very high tensile strength-to-weight ratio and superior cracking resistance behavior. There are also many reported evidences that ferrocement is capable of improving many other engineering properties, such as toughness, fatigue resistance, impermeability, and etc. For some specific applications, where higher tensile resistance is expected, steel bar would be used to form the structure.
Ferrocement mix is made of very rich cement-mortar matrix, which consists of Portland cement and fine aggregate. The type of cement to be used is depends on the service conditions. As for any type of concrete, the cement shall be in good quality. The cement shall be stored in dry conditions, and the stock shall be as new as possible. The fine sand used, which is about 60 to 75 percent of the total ferrocement mix, shall be also in good quality. Typically, the sand shall be hard, strong, non-porous, debris free, free from silt, clay, and other organic impurities. The sand also should not be too fine, which will require more water to achieve the required workability, and this would affect the strength and permeability. Recommended size range for the sand is between 2.36mm and 1.18mm. Apart from these two main ingredients, mixing water is also plays an important role in affecting the properties of the ferrocement mix. The water used shall be at the same quality as drinking water. To improve the performance of the mix, some form of chemical admixtures could be used. Some of the common reason to use chemicals is to (i) improve the workability, (ii) water reduction to increase the strength and reduce the permeability, (iii) water proofing, (iv) improve the durability, (v) to avoid corrosion of wire mesh. Besides chemical admixture, natural admixtures also could be used to improve the durability of the concrete; and the most common natural admixture is fly ash or slag.
In this article, I've discussed on the basics of ferrocement. The follow up articles on ferrocement articles will touch on properties of ferrocement.