Search

Aiming at the problems of insufficient flexural strength and low durability of cement concrete, this paper prepared concrete with different content of epoxy resin（0%, 3 wt%, 6 wt%, 9 wt%） by using epoxy resin as doping phase, and analyzed the influence of epoxy resin on the mechanical properties, micro appearance and durability of cement concrete. The results show that the doping of epoxy resin accelerates the hydration reaction, reduces the number of cracks and pores, and improves the density of concrete. The compressive strength and flexural strength both increased first and then decreased with the increase of resin doping. The compressive strength and flexural strength of the concrete with 6 wt% epoxy resin doping reached the maximum values of 43.8 and 7.9 Mpa respectively when cured for 28 d, which increased by 18.70% and 29.51% respectively compared with the concrete without resin doping. The chloride ion diffusion coefficient of concrete decreases first and then increases with the increase of resin doping amount. The chloride ion diffusion coefficient of concrete with 6 wt% epoxy resin doping content for 28 d is the lowest of 7.7×10-8 cm/s, and the chloride ion corrosion resistance is the best. When the number of freeze-thaw cycles reaches 80, the concrete with 6 wt% epoxy resin doping has the lowest mass loss rate of-0.13%, the highest relative dynamic elastic modulus of 94.86%, the lowest wear amount of 0.66 kg/m², and the wear amount reduction rate of 46.77%. It has excellent durability. [ABSTRACT FROM AUTHOR]

Graphene (G)/graphene oxide (GO) has shown promising applications in improving the mechanics and functionality of cement materials with its excellent mechanical, electrical, and thermal conductivity properties. However, these nanomate rials are difficult to disperse in cement-based materials, which limits their practical application in cement-based composites. Tn recent years, researchers have begun to mix fibers with these nanomaterials into cement-based materials, and its dispersion performance has been greatly improved. Tn this paper, the influence of graphene, GO and other fiber mixture on cement-based composite materials is systematically described from five aspects of material dispersion in cement, cement hydration process, mechanical properties, functionality and durability, which has a guiding role in improving the performance of cement-based composite materials in the future. [ABSTRACT FROM AUTHOR]

Geopolymer is a new green cementitious material, which has many excellent properties in mechanical properties and durability, but also has some shortcomings. It is feasible way to overcome the disadvantages of geopolymer by using the advantages of nano materials. In this paper, the influence of nano materials blending geopolymer on the workability, mechanical properties and durability of the mixture was systematically de scribed. The influence mechanism was summarized and the existing problems of nano modified geopolymer were discussed. The future modification research may include revealing the influence mechanism, focusing on the comp<1tibility and synergy between nano materials and other components, accunnely designing and developing nano core-shell particles suitable for geopolymer reaction system, and quantificationally evaluating the disper sion of nanoparticles in aqueous solution and colloidal environment. Improving the modification effi ciency of nano particles provided a reference for the future research on nano modified geopolymer. [ABSTRACT FROM AUTHOR]

Polymer cement concrete has become an important part of high-performance concrete research, Tn this paper, a polymer emulsion (styrene-butadiene latex,SBL) was adopted to modify high-performance concrete？ and effects of different additive amounts on basic mechanical properties􀀀 toughness􀀀 autogenous shrinkage and chloride penetration resistance of cement concrete were studied. The results show that the compressive strength of cement concrete modified by SBL decreased with the increase of the content of SBL? while the addition of SBL could greatly improve the splitting tensile strength? flexural strength and toughness of concrete. When SBL addition was 1 5% 􀀀 the enhancement was most obvious􀀀 and the increase of splitting tensile strength and flexural strength was 17.4% and 23,8%,respectively. The toughness index reached its peak at 10% SBL? with the increase of 71.1 The total shrinkage value for 24 h after pouring of the modified cement concrete decreased with the increasing addition of SBL. The total shrinkage decreased by up to 35% at SBL. At the same time, the anti-chloride diffusion ability and anti-permeability performance of modified cement concrete were improved obviously. [ABSTRACT FROM AUTHOR]