Compressive strength and AC impedance of mortar made with water-glass-activated slag were investigated as a dependence of modulus (0.5-2.0) and dosage (2-6%) of the water-glass. Results shown that when the dosage of water glass is 2- 4 %, the modulus of the water glass has a little effect on the compressive strength. In the case of the dosage of water glass is beyond 4 %, when modulus of the water glass change from 0.5-1.0, the compressive strength obviously increases with increase of modulus of water glass and when modulus of the water glass change from 1.0-2.0, the modulus of the water glass has a little effect on the compressive strength. The strength increases with increase of the dosage from 2 to 6%. In the case same dosage and modulus, there is a rather good power correlation between the bulk resistance and the activated age. With increase of the dosage, the bulk resistance significantly decreases when the dosage is below 4%. The decreasing degree is small when the dosage is beyond 4%. The decreasing degree derived from the dosage increases with the activated age. The effect of the modulus on the bulk resistance depends on range of the dosage. However, it can be regarded that when the dosage is 4% and 6%, the modulus has small effect on the bulk resistance in the case of all the dosages.

In order to investigate factors influencing workability of recycled aggregates (RA) concrete, such as water amount, sand ratio and RA replacement percentage, 10 pitch of RA concrete was prepared for measurement of workability and a formula was used for calculating effect of water amount on slump of RA concrete. Experimental results and formula induction indicated that there are logarithmic relationship between flowability of fresh concrete and water amount and ratio of aggregates to cement . The flowability will logarithmically increase with increase of water amount and decrease of aggregates cement ratio. The optimum sand ratio for RA concrete can be determined by measurement of slump. Slump decreases with RA replacement percentage and there is a very good linear relationship between them. When water amount increases, slump increases and when replacement percentage of RA increases, slump decrease. Under different water amount, effect degrees of replacement percentage of RA on slump are very similar and under different replacement percentage of RA, effect degrees of water amount on slump are also very similar.

In this investigation, calorimetry, quantitative X-ray diffraction analysis and the scanning electron microscopy were applied to explore the mechanism of hydration modification of cement with diethanol-isopropanolamine (DEIPA). It showed that the addition of DEIPA favoured the strength development on 3 and 28 days, but was undesirable for the 1d strength. The reason for this was that the dissolution of intermediate phase being promoted by DEIPA participated in the aluminate reaction interrupting the normal hydration of C3S. Appropriate adjustment on SO3 content in the cement was able to slow down the rate of aluminate reaction allowing C3S to react in a right fashion, which gave an optimum strength enhancement at early ages. The addition of DEIPA also impacted the formation of hydrates. Significant differences can be recognized in quantities, chemical compositions and the morphologies of hydrates in blank sample and the DEIPA-dosing ones. With the help of SO3 adjustment in cement with DEIPA, a great number of hydro-sulfoaluminates precipitated at the early stage of hydration to decrease the porosity of hardened cement pastes, which contributed to the strength gain of cement.