Research On The Preparation And Properties Of Steel Slag Sand Masonry Mortar

In this subject, the waste steel slag sand, as the main raw material, was used to prepare the steel slag sand mortar with good mechanical and operational properties. And we discussed the effect the size of steel slag sand, cement-sand ratio and replace quantity of river sand on the mechanical properties, durability and stability of masonry mortar, considering the integrated performance indicators, an optimal ratio of masonry mortar was obtained.Slag sand contains a certain amount of f-CaO, so too much content of slag sand will cause bad mortar stability, this characteristics of steel slag sand has greatly restricted its application. In this paper, the f-CaO content of different sizes of steel slag sand was determined, and by research on expansion property of mortar which prepared by steel slag sand with different store time, the conclusions are as follows:1. By contrast experiment about different sizes of steel slag sand,the result show that the greater range of steel slag sand particle size, the less water needed. Controling the consistency in 140mm, the compressive and flexural strength of full grade of steel slag sand mortar were greater,ang expansion rate was lower.2. Incorporation of river sand will reduce the expansion rate of mortar, and with the increase in the amount of river sand mixed, expansion rate showed a decreasing trend, this will help to improve the volume stability of mortar; with river sand to replace steel slag can improve the strength of mortar, the greater replace quantity of river sand, the greater the intensity. Experiments show that when the dosage of river sand is 60%, the strength and expansion rate of mortar is close to the replace quantity of river sand is 100%.3. According to comparative experimen of adding water reducing agent or not of mortart shows that the addition of poly-carboxylic acid superplasticizer in steel slag sand masonry mortar can effectively improve the flexural strength and compressive strength of mortar, and the addition of superplasticizer to increase of compressive strength is more obvious than flexural strength。4. Experimental preparation of steel slag sand masonry mortar has good frost resistance, weatherability, alkali tolerance and heat resistance can meet the construction specifications. However, due to the larger content of steel slag sand can easily prone to expansion and then make the volume stability of mortar deterioration, in the experiment, it selects the appropriate mixing amount of river sand to improve the expansion property and thereby enhances the stability of mortar, and the incorporation of appropriate amount of river sand have a beneficial effect on frost resistance of mortar. Durability test uses full particle size and different cement-sand ratio steel slag sand to study, the lager cement-sand ratio can lead to the expansion rate is too large of mortar, but the frost resistance of different cement-sand ratio masonry mortar has small difference. Experiments show that when cement-sand ratio is1:3 and mixing amount of river sand is 60%, it has good performance of durability of steel slag sand masonry and each performance index can meet the requirements.5. With the increase of particle size, the content of f-CaO will decrease in steel slag sand, in the range of 0-4.75mm particle size of steel slag sand, the f-CaO content is at least of three, its particle size steel slag mortar is beneficia to the volume stability; the longer of deposition in different sizes of steel slag sand, the better of its stability, after 60d storage, the trend of expansion rate tends to stable; in the curing time is 7 to 15 days, the expansion rate of mortar specimens increased by a big margin, with the continuous extension of curing time, expansion rate changes little, So The expansion rate of mortar with a certain curing time can be as the evaluation index of mortar which prepared by steel slag sand with different store time.