Effect of some Key Factors on the Strength of Recycled Concrete

Abstract

Because there exists a used cement mortar layer outside the recycled aggregate, there are more interfaces inside recycled concrete, which would result in recycled concrete has different properties from ordinary concrete. In this paper, the effect of such key factors for recycled concrete mix ratio as water-cement ratio, cement strength, sand rate, maximum granule diameter and gradation on the properties of concrete with recycled coarse aggregate was studied by experiment, and the some useful suggestion for mix ratio of recycled concrete was provided.

Direct Observation of Hydroxyapatite Nanoparticles <i>In Vivo</i>

“…The fresh 18 F, manufactured by cyclotron, was added during the precipitation of nano-HAP. Nano-HAP crystals were prepared by a wet-chemical route, which was reported detailed in our previous paper [5]. The phase composition of the HAP nanoparticles were identified by XRD ( χ'Pert PRO, PANalytical B. V.), Fourier transform infrared spectroscopy (FT-IR, VERTEX 70, Bruker, Germany).…”

The Calculation of Unit Water Use in Recycled Concrete

“…Besides, Literatures [3][4][5] all show that the unit water use in recycled concrete should be increased on the base of ordinary concrete, but all these literatures have not given the specific calculating formulas. The authors once researched the combination of the mixed coarse aggregate added natural sand by experiment [6,7], put forward the calculating formula for extra adding the water use, but the calculation of other else aggregate combination has not been discussed.…”

“…In fact, all the three formulas may be expressed by Eq. (7) in the unified way. For the condition (1), the recycled aggregate lies in the saturated surface-dry condition, i.e.…”