Fibers are added to concrete to improve several of its properties. The ability of polypropylene fibers to modify different characteristics of concrete is controversial. This paper presents results on the influence of adding polypropylene fibers (0.1 to 0.2 percent by volume) on mortar permeability and plastic shrinkage. The influence of adding polypropylene fibers on the early stages of shrinkage is studied with 120 x 15 x 3 cm specimens. These were fabricated in mortar and then held in a chamber with controlled temperature and ventilation. The specimens have a special geometry to enable the shrinkage measurement in the plastic state, and the influence of this on mortar cracking. The variables studied were: water-cement ratio, sand-cement ratio, and fiber content. In addition, the ability of fiber concrete to absorb water and its permeability to CO2 were tested. Water absorption was measured in accordance with French standard NFB 10.502. Carbonation was studied by introducing fiber mortar specimens in a chamber saturated with CO2 and comparing the results with natural carbonation. Results show that the addition of fiber reduces plastic shrinkage when compared with the same type of mortar without fibers. Concerning water absorption, it is reduced when water-cement ratio is about 0.5; however, when the water-cement ratio is higher than 0.5, this behavior is reversed and the fiber mortar is more water absorbent. Accelerated and natural carbonation show that CO2 diffusion increases in mortar with the highest amount of fibers.

Precast thin ferrocement planks have replaced wood for a variety of applications. Present knowledge about joining them using steel bolts or similar means is very limited. While bolted connections are commonly employed in steel construction, their suitability for connecting precast reinforced concrete or ferrocement elements is yet to be fully investigated, particularly when subjected to both bending and direct tension. A series of tests were carried out at the Structural Engineering Research Centre, Madras, India, on precast ferrocement planks connected together using steel bolts for transferring tension and flexural moment

A brief review of the literature on cellulose fiber reinforced cement is presented, followed by the results of an experimental study concerned with the effects of mechanical and chemical pulps on the performance characteristics of neat cement paste in the fresh and hardened states. The mix proportions and manufacturing techniques used in this study for the production of cellulose-cement composites are reviewed. The air content, setting time, and drop in workability with time are compared for plain cementitious materials and those reinforced with 1 and 2 percent mass fractions of mechanical and chemical pulps. The flexural and compressive strength and toughness characteristics, impact resistance, specific gravity, and water absorption capacity of plain and fibrous materials are also compared. Effects of moisture content on the flexural performance of plain cementitious materials and those reinforced with mechanical pulp are discussed.

Presents comprehensive test data on the tensile behavior of 12.5 cm thick ferrocement plates. The main variables investigated were mesh geometry, specific surface, volume fraction, mesh yield strength and skeletal bars. The specimens were specially designed to insure failure in the gage length. The matrix was proportioned for high strength, high workability, and high durability with low water-to-binder ratio, and 50 percent fly ash replacement. Cracking and deformation were monitored throughout the loading range. The results showed that the composite properties of elastic modulus and ultimate tensile strength could be satisfactorily predicted. However, the cracking behavior for a wide range of mesh geometry could not be satisfactorily predicted by a single unique relationship. There was, however, good correlation between the composite properties of ultimate tensile strength and ultimate flexural strength. The results show that by suitable design of the matrix and the reinforcement, high-strength, ferrocement sheets with high crack resistance can be developed for a variety of structural applications.

Flexural behavior of sandwich beams reinforced with thin layers of steel-fiber reinforced mortar was studied in this investigation. The effect of variations in thickness of the reinforced layer on the modulus of rupture, Young's modulus, and toughness of the member was investigated. This investigation considered one single specimen size with fiber reinforced mortar using one fiber geometry and content. Steel fibers with 0.6 x 0.3 mm cross section and 18 mm long were used. The specimens were cast in 100 x 100 x 350 mm molds. Eight series of sandwich beams with different thicknesses of the reinforced layer were tested. Experimental results indicated that sandwich beams can have strength and toughness comparable to fully fiber reinforced beams. The minimum thickness of the fiber reinforced layer required to impart ductile behavior to the sandwich beam was found to be about one-sixth of the beam depth.