California bearing ratio test

California bearing ratio tests are used to evaluate subgrades for pavements. These tests may be carried out in the field or in the laboratory. Such tests determine the resistance to penetration of a subgrade soil relative to that of a standard crushed-rock base. 

Stabilisation is a much slower process, which occurs progressively over several months, and involves the reaction of lime with the siliceous and aluminous components of the soil. The lime raises the pH to above 12, which results in the formation of calcium silicates and aluminates. These are believed to form initially as a gel, which coats the soil particles, and which subsequently crystallises as calcium silicate/aluminate hydrates. Those hydrates are cementitious products, similar in composition to those found in cement paste. The rate of crystallisation is temperature dependant and may take many months to reach completion. The resulting gain in strength (measured by the California Bearing Ratio Test [26.11]) is progressive, as illustrated in Fig. 26.2. 

California Bearing Ratio (CBR) is the measure of the load-bearing eapacity of a soil, obtained using the California Bearing Ratio test. 

One-dimensional swell or settlement potential of cohesive soils California Bearing Ratio (CBR) of laboratory-compacted soils Bearing ratio of soils in place Permeability of granular soils by constant head pH of soil for use in corrosion testing... 

ASTM, Standard Test Method for CBR (California Bearing Ratio) of Laboratory-Compacted Soils, ASTM D1883-05, American Society for Testing and Materials, West Conshohocken, PA, 2005. 

CEN EN 13286-47. 2012. Unbound and hydraulically bound mixtures, Part 47 Test methods for the determination of the California bearing ratio, immediate bearing index and linear swelling. Brussels CEN. 

ASTM D 1883-7e2. 2007. Standard test method for CBR (California bearing ratio) of laboratory-compacted soils. West Conshohocken, PA ASTM International. 

The second test, BSENISO 12236 Static Puncture Test (California Bearing Ratio (CBR) Test) is referred to a large-size puncture test and appropriate to the situation of aggregate consolidation. It is also commonly referred to as the CBR test, because it is based on the ASTM D1883 CBR test performed by measuring the pressure required to penetrate a soil sample with a plunger. 

D4429-93 Standard Test Method for CBR (California Bearing Ratio) of SOILs in Place. 

Heave measure oedometer expansive test (swelling potential and swelling pressure), or swell in California Bearing Ratio (CBR) ... 

A large-size puncture test has been developed which uses a conventional soil-testing California bearing ratio (CBR) plunger and mold. The penetrating steel rod is 50 mm in diameter and the geotextile is firmly clamped in an empty mold 150 mm in inside diameter. This test is formalized as ASTM D6241 and ISO 12236. 

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