Performance of High Performance Expanded Concrete at Low Temper

  • In the recommended dosage range (6% -8%), the mortar strength of the expansive agent is slightly lower than that of the reference concrete at 3d and 7d age. When the content is 10%, the strength of the mortar decreases The free expansion and limiting expansion of the mortar increases with the increase in the amount of bulking agent. The smaller the expansion index, the greater the effective expansion energy, the greater the compensation shrinkage. From the results of compressive strength, the compressive strength of the concrete with the expansive agent is obviously reduced at 3d level, and the strength of 28d is obviously increased. Concrete in the absence of no constraints, the expansion of the early structure of the concrete loose, the intensity decreased, but later with the strength of high-strength concrete development, expansion agents continue to play a role, so that the internal structure of concrete dense, no strength of concrete 28d Reduce the effect. The porosity of the high strength concrete with the expansive agent is slightly lower, the pore content is higher and the pore content in the range of less than 10mm is slightly increased, but this does not significantly affect the early shrinkage performance of the concrete, but the late shrinkage of the concrete There is a downward trend. Durability is a high strength concrete that must have performance. The mechanism of the durability of high performance expansive concrete is that the blending agent blended with HPC, silicon powder, fly ash, ground slag and so on can reduce the diffusion performance. It is worth mentioning that in the HPC complex ground slag and expansion agent or fly ash and expansion agent can be compared with one of the two can further reduce the diffusion of HPC performance, the effect is even better than the single-doped silica fume , It is believed that the high strength of the anti-permeability is not necessarily high, and other mineral fine admixture of composite use can improve the anti-permeability of concrete play a significant role. The improvement of impermeability ensures the necessary features of high performance concrete durability. From the point of view of fracture control, high calcium fly ash has better effect of low hydration heat than ground slag, while high calcium fly ash is higher due to higher hydration heat of higher activity slag slag Complex admixture and fine admixture not only reduce the hydration heat in the system, especially in the temperature generated by the crack control play a considerable role. used light towers anti aging fix cracked concrete rural road medium steel wheel compactor road hard infrastructure save oil