Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexur...Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexural strength, brittleness index （σF/σC） and abrasion resistance can be improved significantly by the addition of PP fiber and SBR polymer latex. The relationship between the flexural strength and abrasion resistance was analyzed, showing a good linear relationship between them. The reinforced mechanism of PP fiber and SBR polymer latex on cement mortar was analyzed by some microscopic tests. The test results show that the addition of SBR polymer latex has no significant influence on the cement hydration after 7 d curing. Adding SBR polymer latex into cement mortar can form a polymer transition layer in the interfaces of PP fiber and cement hydrates, which improves the bonding properties between the PP fiber and cement mortar matrix effectively.展开更多
Modified polypropylene fiber reinforced cement compos-ites were investigated in their abrasion resistance andsurface morphology. The test results showed the addingof fiber could noticeably improve the abrasion resista...Modified polypropylene fiber reinforced cement compos-ites were investigated in their abrasion resistance andsurface morphology. The test results showed the addingof fiber could noticeably improve the abrasion resistanceof composite. The bonding and friction of fibers/cementwere the main contribution to abrasion resistance im-provement, which resulted from the surface morphologyobservation.展开更多
Apart from many advantages,High Strength Concrete(HSC)has disadvantages in terms of brittleness and poor resistance to fire.Various studies suggest that when polypropylene(PP)fibers are uniformly distributed within co...Apart from many advantages,High Strength Concrete(HSC)has disadvantages in terms of brittleness and poor resistance to fire.Various studies suggest that when polypropylene(PP)fibers are uniformly distributed within concrete,they play an active role in improving spalling resistance of concrete when exposed to elevated temperature while having no adverse effect on its mechanical properties.Therefore,there is a necessity to quantify the effect of the addition of polypropylene fibers in terms of the fiber dosage,the strength of the concrete,and the residual mechanical properties of fiber-reinforced concrete under exposure to high temperature from fire.The study was carried out on three water/cement(w/c)ratios(0.47,0.36&0.20)using granite aggregate for determining short term mechanical properties of Polypropylene fiber reinforced concrete in comparison to control mix.The experimental program includes 100×200 mm&150 x 300 mm cylinders with fiber volume of 0.5%,that were subjected to temperatures exposures of 400°C and 600°C for durations of 1 hour.From the results,it was observed that no significant enhancement in mechanical properties such as modulus of elasticity,Poisson’s ratio,split tensile strength,flexural strength,and compressive strength was observed at room temperature and at elevated temperatures.展开更多
The use of recycled aggregate(RA)instead of natural aggregate(NA)in concrete is necessary for environmental protection and the effective utilization of resources.The addition of recycled aggregates in concrete increas...The use of recycled aggregate(RA)instead of natural aggregate(NA)in concrete is necessary for environmental protection and the effective utilization of resources.The addition of recycled aggregates in concrete increases shrinkage,porosity and decreases the mechanical properties compared to that of normal concrete.This study was aimed at investigating how the addition of various proportions of polypropylene and steel fiber affect the mechanical properties of recycled aggregate concrete(RAC).The natural coarse aggregates(NCAs)used in the production of normal concrete(NC)were replaced in 30%and 50%proportions by recycled coarse aggregates(RCAs)obtained from the demolished buildings.In this case,a polypropylene fiber(PF)content of 0.1%and steel fiber(SF)1%and 2%volume fractions were used,along with hybrid fibers-a combination of the two.While the material performance of RAC compared to NC is analyzed by reviewing existing published literature,it is not evident what the use of RCAs and hybrid fibers have on the mechanical properties of concrete.The results showed that the compressive strength,flexural strength and impcat resistance of RAC were reduced as the percentage of RCAs increased.It was observed that the compressive strength was increased with the addition of 1%steel fiber in the RAC.The flexural and impact performance of steel fiber-reinforced concrete(Specimens NC and RAC)was increased as the volume fractions of steel fiber increased.The hybrid fiber reinforced concretes showed the best results in their mechanical performance of all the concrete groups.展开更多
基金Funded by the Science Project from Department of Communication of Hubei Province
文摘Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexural strength, brittleness index （σF/σC） and abrasion resistance can be improved significantly by the addition of PP fiber and SBR polymer latex. The relationship between the flexural strength and abrasion resistance was analyzed, showing a good linear relationship between them. The reinforced mechanism of PP fiber and SBR polymer latex on cement mortar was analyzed by some microscopic tests. The test results show that the addition of SBR polymer latex has no significant influence on the cement hydration after 7 d curing. Adding SBR polymer latex into cement mortar can form a polymer transition layer in the interfaces of PP fiber and cement hydrates, which improves the bonding properties between the PP fiber and cement mortar matrix effectively.
基金Suppurted by Key Subject Foundation of Shanghai Educational Committe and NSF
文摘Modified polypropylene fiber reinforced cement compos-ites were investigated in their abrasion resistance andsurface morphology. The test results showed the addingof fiber could noticeably improve the abrasion resistanceof composite. The bonding and friction of fibers/cementwere the main contribution to abrasion resistance im-provement, which resulted from the surface morphologyobservation.
文摘Apart from many advantages,High Strength Concrete(HSC)has disadvantages in terms of brittleness and poor resistance to fire.Various studies suggest that when polypropylene(PP)fibers are uniformly distributed within concrete,they play an active role in improving spalling resistance of concrete when exposed to elevated temperature while having no adverse effect on its mechanical properties.Therefore,there is a necessity to quantify the effect of the addition of polypropylene fibers in terms of the fiber dosage,the strength of the concrete,and the residual mechanical properties of fiber-reinforced concrete under exposure to high temperature from fire.The study was carried out on three water/cement(w/c)ratios(0.47,0.36&0.20)using granite aggregate for determining short term mechanical properties of Polypropylene fiber reinforced concrete in comparison to control mix.The experimental program includes 100×200 mm&150 x 300 mm cylinders with fiber volume of 0.5%,that were subjected to temperatures exposures of 400°C and 600°C for durations of 1 hour.From the results,it was observed that no significant enhancement in mechanical properties such as modulus of elasticity,Poisson’s ratio,split tensile strength,flexural strength,and compressive strength was observed at room temperature and at elevated temperatures.
文摘The use of recycled aggregate(RA)instead of natural aggregate(NA)in concrete is necessary for environmental protection and the effective utilization of resources.The addition of recycled aggregates in concrete increases shrinkage,porosity and decreases the mechanical properties compared to that of normal concrete.This study was aimed at investigating how the addition of various proportions of polypropylene and steel fiber affect the mechanical properties of recycled aggregate concrete(RAC).The natural coarse aggregates(NCAs)used in the production of normal concrete(NC)were replaced in 30%and 50%proportions by recycled coarse aggregates(RCAs)obtained from the demolished buildings.In this case,a polypropylene fiber(PF)content of 0.1%and steel fiber(SF)1%and 2%volume fractions were used,along with hybrid fibers-a combination of the two.While the material performance of RAC compared to NC is analyzed by reviewing existing published literature,it is not evident what the use of RCAs and hybrid fibers have on the mechanical properties of concrete.The results showed that the compressive strength,flexural strength and impcat resistance of RAC were reduced as the percentage of RCAs increased.It was observed that the compressive strength was increased with the addition of 1%steel fiber in the RAC.The flexural and impact performance of steel fiber-reinforced concrete(Specimens NC and RAC)was increased as the volume fractions of steel fiber increased.The hybrid fiber reinforced concretes showed the best results in their mechanical performance of all the concrete groups.
