Polypropylene fibre reinforced concrete reinforcement

Saje, D., Bandelj, B., SustersiC, J., Lopatic, J., Saje, E, 2011. Shrinkage of polypropylene fibre-reinforced high-performance concrete. Journal of Materials in Civil Engineering, 23(7), pp. 941-953. 

A. Bentur, S, Mindess and G. Vondran, Bonding in polypropylene fibre reinforced concrete , int J. Cem. Comp. Ltwt. Concr. 11,1989,153 158. 

L. Tu, D. Kruger and P.A.B. Carstens, Effects of the increased surface wettability on the polypropylene-concrete interfacial bonding and the properties of the polypropylene fibre reinforced concrete , in Y. Ohama and M. Puterman (eds) Adhesion between Polymers and Concrete, RILEM Proceedings PRO 9, RILEM Publications, Bagneux, 1999, pp. 267-284. 

A.E. Naaman, S.P. Shah and J.E. Thorne, Some developments in polypropylene fibres for concrete , in G.C. Hoff (ed.) Fiber Reinforced Concrete, SP-81, American Concrete Institute, Farmington Hills, Ml, 1984, pp. 375-396. 

G. Spadea and G. Frigione, Mechanical and rheological behaviour of polypropylene fibre reinforced concrete , //Cemento. 2,1987,173-185. 

B. Barr and P.D. Newman, Toughness of polypropylene fibre reinforced concrete . Composites. 16,1985, 48-53. 

R.V. Velasco, R.D. Toledo Filho, E.M.R. Fairbairn, P.R.L. Lima and R. Neumann, Spalling and stress-strain behaviour of polypropylene fibre reinforced HPC after exposure to high temperatures , in M. di Prisco, R. Felicetti and G.A. Plizzari (eds) Fibre-Reinforced Concretes BEFiB 2004, Proc. RILEM PRO 39, RiLEM Pubiications, Bagneux, 2004, Vol. 1, pp. 699-708. 

As it is commonly known and applied for a long time, the properties of paste can be improved by reinforcement with the fibres. For example, the production of asbestos-cement materials started 80 years ago. The fiber reinforcement technology has been developed extensively for the last 20 years and the other fibres has been taken into account, first of all the steel fibres, but also the carbon, glass, resin, polypropylene and cellulose fibres as well. The fibres reinforcement gives the pos-sibihty to enhance the flexural and tension strength, as well as the impact resistance. The fibre composite modifies the properties of concrete by control cracking and the mode of failure by means of post—cracking ductility. 

Qian, C.X. Stroeven, P. (2000). Development of hybrid Polypropylene-Steel Fibre Reinforced Concrete, Cement and Concrete Research, Vol. 30, No.l, pp. 63-69, ISSN 0008-8846. 

Despite the reduced workability of FRC, recent studies have shown that it is possible to produce fibre-reinforced self-compacted concrete (FR-SCC), with good flow properties and suitable properties. Akcay and Tasdemir (2012) have studied steel fibre in FR-SCC and found that the main parameter affecting the flowability of FR-SCC is the geometry of fibres, rather that the fibre strength. El-Dieb and Taha (2012) show that suitable workability of FR-SCC depends on the fibre content. For polypropylene fibres, the maximum fibre content should be 1000, 1200 and 1300 g/m for SCC mixtures with cement content 350, 400 and 500 kg/m respectively. For steel fibres, one should limit the fibre aspect to 50, 90 and 100 kg/m for SCC mixtures with cement content of 350, 400 and 500 kg/m respectively. 

Ali et al. (1972) studied the effects of carbon fibre orientation and distribution in carbon fibre-reinforced concrete (CFRC). Instrumented impact test results using low-modulus carbon fibres demonstrated substantial increases in impact strength and fracture energy in proportion to the volume fraction of fibres used. Also, the impact strength increases as fibre content is increased. Improvement in fracture energy for polypropylene FRC was reported between 33 and 1000% (Mindess and Vondran, 1988 Banthia et al., 1987a). 

Banthia and Nandakumar (2003) have employed secondary polypropylene micro-fibres to enhance the deformation of steel fibre-reinforced concrete. More recently, Dawood and Ramli (2012) proposed the combination of steel fibres with synthetic and palm fibres as a means of reducing the corrosion problems of fibres and improving the flowing and mechanical properties of concrete. Lee et al. (2012) have shown that the blending of nylon and polypropylene fibres improves the spalling protection of FRC subjected to fire. Azhari and Banthia (2012) have blended carbon fibres and nanotubes in the development of smart stmcture materials, such as strain sensors. 

Mindess, S., Vondran, G., 1988. Rroperties of concrete reinforced with fibrillated polypropylene fibres under impact loading. Cement and Concrete Research, 18(1), pp. 109-115. 

This group of materials, also called fibre-reinforced concretes (FRC), contains concretes and mortars reinforced with short fibres, distributed at random or arranged in a certain way also as mats and fabrics. The fibres are of different materials steel, glass, polypropylene, asbestos, etc., as well as natural organic... 

Traditional reinforcement of concrete elements in the form of steel bars and prestressing cables or tendons is not studied here as it is mentioned in Section 2.3.1 and only dispersed fibre reinforcement is considered. Macrofibres are usually of 10-60 mm in length and 0.1-1.0 mm in the least dimension. Micro-fibres are of 10-30 pm in diameter and below 10 mm in length. There are several kinds of microfibres non-metallic, including asbestos, polypropylene, mica, wollastonite and xonotlite, and steel fibres. In the following chapter both these gronps of fibres are considered made with different materials (cf. ACT 544.1R-96). 

Polypropylene fibres have been produced since 1954 and since 1965 were applied as concrete reinforcement. Initially, the plain and straight polypropylene fibres were used, but their bond to a cement matrix was insufficient because mechanical interlocking was weak and the chemical bond did not exist at all. This is the reason that single filaments with fibrillated surface and twisted strands are now used. 

Naaman, A. E., Shah, S. P., Throne, J. L. (1984) Some developments in polypropylene fibers for concrete , in Proc. Int. Symp. Fibre Reinforced Concrete, SP-81, Detroit ACI, pp. 375-96. 

Results obtained by Ramakrishnan and Lokvik (1992) concerned concrete specimens subjected to flexure and reinforced with four types of fibres straight, corrugated and hooked steel-fibres, and polypropylene fibres up to 1 % volume. The relations between number of cycles N and maximum fatigue stress divided by the modulus of rupture are shown in Figure 11.11 as estimated regression lines for different kinds of fibres. The proposed formula for prediction of the fatigue behaviour is the following ... 

Beams made with high early-strength fibre-reinforced concrete were tested by Naaman and Hammoud (1998) and steel and polypropylene fibres were applied separately and as a hybrid reinforcement. Loading range was 10-90% and 10-80% of the ultimate static strength. In Figure 11.12, the... 

The general conclusion is that while there are many well-established procedures to design ordinary concretes, which may be extended also to cover high performance concrete and ultra high performance concrete, there are no such methods for polymer modified concretes and for fibre-reinforced concretes. Also for fibres other than short steel ones (glass, polypropylene, long steel fibres, etc.) there are no general recommendations. 

In road pavements, high performance concrete with carefully selected aggregate and compressive strength up to 135 MPa exhibited a level of abrasion resistance from studded tyres similar to massive granite. According to laboratory tests, this concrete may last four times longer than traditional concrete of 55 MPa. The addition of a small amount of steel and polypropylene fibres improves crack control in elements reinforced with traditional steel bars, for example, in deep beams where steel fibres partly replace stir-... 

R.F. Zollo, J.A. liter and G.B. Bouchacourt, Plastic and drying shrinkage in concrete containing collated fibrillated polypropylene fibre , in R.N. Swamy, R.L. Wagstaffe and D.R. Oakley (eds) Developments in Fibre Reinforced Cement and Concrete, Proc. RILEM Symp., Sheffield, 1986, paper 4.5. 

Crack control in set and hardened concrete The low modulus polypropylene fibres at the content of 0.1% by volume applied for plastic shrinkage crack control are not effective for crack control of hardened concrete, as shown in Table 10.4 [50]. However, Sanjuan etal. [55] found that low volume propylene reinforcement could lead to somewhat decreased initial cracking of the concrete in the plastic stage, and this resulted in somewhat lower corrosion rates of steel reinforcement in the hardened concrete. The data indicate that only the fibres which received special surface treatment of roughening had an influence on reducing cracking. 

Al-Tayyib and Al-Zahrani [78,79] showed that adding 0.2% polypropylene fibres to the concrete effectively enhanced the durability of the concrete skin when exposed to severe marine environments, and improved the concrete durability by retarding the corrosion of the reinforcing steel. 

H. Krenchei and S.P. Shah, Restrained shrinkage tests with polypropylene fiber reinforced concrete , in S.P. Shah and G.B. Batson (eds) Fibre Reinforced Concrete Properties and Applications, SP-105, American Concrete Institute, Farmington Hills, Ml, 1987, pp. 141-158,... 

S. Mindess, A. Bentur, C. Yan and G. Vondran, Impact resistance of concrete containing both conventional steel reinforcement and fibrillated polypropylene fibres , ACUournaim, 1989, 545 549. 

C.X. Qian and P. Stroeven, Development of hybrid polypropylene-steel fibre reinforced concrete , Cem. Concr. Res. 30, 2000,63-69. 

R.N. Swamy and M.W. Hussin, Woven polypropylene fabrics - an alternative to asbestos forthin sheet applications , in R.N. Swamy and B. Barr(eds) Fibre Reinforced Cement and Concrete, Recent Deveiopments, Elsevier Applied Science, UK, 1989, pp. 90-100. 

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