Portland Cement Grout Research Articles

Injection d'ancrages à base de ciment Portland dans l'arctique

During summer, it is possible to inject Portland cement grout in the Arctic because there is a layer of unfrozen rock surface which is approximately 2 m deep. During the month of August, the temperature of the unfrozen rock layer reaches +5 °C at a depth of 1 m, which allows the Portland cement to harden in good conditions and to acquire its full strength.After 7 days, the mean shear strength to failure at the rod–group contact, determined when the anchorages were pulled out, was 10 MPa. After 1 year, this strength was close to 20 MPa. These results are similar to those recorded in Sherbrooke for the same grout formulas. Key words: anchorage, cement grout, rock, Arctic, tearing off. [Journal translation]

Carbonation of geothermal grouts — Part 1: CO2 attack at 150°C

The normal practice of adding fine silica to portland cement grouts for geothermal wells to overcome strength regression due to the increased temperature has been shown to result in a greater rate of carbonation of the hardened grout. Carbonation is controlled not by permeability but by calcium hydroxide content at 150°C. It is concluded that the optimum silica addition for geothermal fluids which contain high levels of CO2, is about 15–20% to obtain the longest life, although actual lifetimes will have to be determined by downhole exposure.

Development of mechanical properties of ordinary Portland and Oilwell B cement grouts

Synopsis The compressive strength and dynamic elastic modulus of ordinary Portland cement (OPC) grouts typical of those used for structural connections in steel jacket offshore platforms has been measured. The main aim of these tests has been to provide baseline data for grout selection and development. Variables tested include water/cement ratio (0·3 to 0·5). OPC and Oilwell B cement, fresh and sea-water for mixing, curing temperatures of 8 and 20°C and the incorporation of superplasticisers. Properties have been measured at ages of I day to 1 year. OPC grouts show a significantly more rapid development of properties at early ages than Oilwell B cement grouts, but the differences are minimal after 7–28 days. Other variables have expected effects on the grout properties. Good correlations of both strength and modulus with ultrasonic pulse velocity have been obtained, and hence greater use can be made of this non-destructive test in future work. Values of dynamic Poisson's ratio calculated from the other properties show a dependence on both strength and water/cement ratio.

Prestressing System for H. B. Robinson Nuclear Plant

A prestressing steel tendon was designed and used for vertical prestressing of the containment. It consisted of six high strength steel bars within a galvanized steel pipe. The tendon was shop assembled with minimum field assembly required. Procedures were developed to protect the tendon from corrosion during a lengthy field construction period and a special portland cement grout mix was developed for final grouting. The entire 150 foot high tendon was grouted once after tests showed the procedures to be successful. The paper describes the containment, the structural function of the tendons, tests which were run on tendon materials and hardware, erection of the tendons, stressing and grouting of the tendons.

Mixing-In-Place Soil and Portland Cement

Construction methods can be found to mix portland cement grout and soil in place below ground at the rate of 1,000 cu yd a day at $8 to $15 per cu yd. When such methods and apparatus are developed, there will be widespread application in the field of underground construction. Among the more important applications may be stabilizing sand deposits under nuclear power plants in earthquake regions.

Rigid Pavement Maintenance for Airfields

The advent of jet aircraft has necessitated a reevaluation of pavement maintenance with respect to smoothness and reducing the probability of foreign object (debris) damage to jet engines and tires. The repair of spalled joints is one facet of rigid pavement maintenance for which repair techniques and materials have been developed and successfully used. The portland cement grout bonding technique (PCA-Acid Etch), using portland cement mortars or concretes, is discussed briefly and referenced. The recently developed method using epoxy resin mortar or concrete is explained in detail using an actual major repair project accomplished under quite adverse temperature conditions. The advantages and disadvantages of both methods are mentioned and performance is cited.