Application of slag-alkali binders in jet cement grouting for soil consolidation

Introduction. The study proves actuality of the problem connected with obtaining efficient slag-alkali binders for usage in soil jet cement grouting. Replacement of usual portland cement for a slag-alkali binder in geotechnical underground construction activities allows solving a problem of waste (slag) utilization and increase economic efficiency of the soil jet cement grouting. In view of cement grouting technology features and possibility of usage cementation mixtures with various engineering characteristics for different soil types, a broad nomenclature of slag-alkali compositions can be used for obtaining soil-concrete structures. Materials and methods. Different types of slag were studied as constituents of composite binders. The PTs 500 D0 cement was taken as the basic portland cement. Standard requirements for cementation mixtures of mixing and pump facilities for soil-concrete bodies became the criteria. Investigations of hydration and structure formation during hardening of slag-alkali binders and soil-concretes on their base were conducted using a system of physical and chemical methods. Evaluation of construction and engineering properties of the composite slag-alkali binder was accomplished in accordance with the methods as per GOST 10181-2014 and GOST 5802-86 state standards. Results. Results of analysis how the slag type and amount influence the physical and mechanical properties of the binder used for jet soil cementation are presented. The article shows improvement of physical, mechanical, process and usage properties of the slag-alkali binder. General mechanism of impact of the slag on properties of the cementation mixture were revealed. Conclusions. Efficiency of application of the slag as an active component of the composite binder for jet cementation in geotechnical construction was theoretically substantiated and experimentally demonstrated. General applicability of the obtained concrete mixture based on the slag-alkali binder is stated for usage in cementation methods of improvement of technical parameters of concrete mixture and concretes. A classification of expanding cements possessing various expansion degrees was suggested for solving different construction problems.