Testing of resin compositions for use in construction BS 6319 Part 1: Method for preparation of test specimens
This Part of this British Standard gives a general introduction to the testing of resin compositions and describes a procedure for obtaining samples of resin compositions and preparing test specimens under either declared practical conditions or more closely controlled laboratory conditions. It is applicable to thermoset cold curing resin formulations
e.g. epoxide, polyester, acrylic, polyurethane. These formulations may include liquid resins, liquid or powder hardeners, aggregates and fillers, and include polymer based grouts.
- Cold curing resin system :- A resin system that can harden without the external application of heat. NOTE :- This is the principal type of system used in the construction industry.
- Cure :- The process leading to permanent hardening of a resin by chemical reaction, such as by cross-linking
- Exotherm :- The heat evolved when a synthetic resin hardens
- filler :- A solid material in powder, granular or fibrous form that is added to a synthetic resin system to reduce cost, exotherm and shrinkage and often increase hardness, abrasion resistance, heat distortion temperature or other specifically selected property of a cured system. Fillers may also modify the flow properties of the system before cure. Coarse fillers are often referred to as aggregates in the same sense as in concrete technology.
- Hardener :- A material that chemically combines with a synthetic resin to give a hardened product NOTEThe terms catalyst, initiator, promoter and accelerator, may also be encountered in this connection and are used to describe a hardener or an additional component necessary for the hardening process. The term curing agent is sometimes used in this sense but conflicts with its meaning in concrete technology and is therefore a deprecated term in this context.
- Pot life ;- The time elapsing between the blending of a resin with its hardener and that stage in its reaction when it is no longer suitable for its intended application.
- Resin concrete :- A blend of resin and hardener with graded aggregate where a significant proportion of the aggregate is retained on a 5.00mm BS410 test sieve.
- Resin grout :- A resin system, with or without fillers, of sufficient mobility to be pumped, poured or injected, according to design, into cracks, fissures or voids.
- Resin mortar :- A blend of resin and hardener with graded aggregate where a small proportion of the aggregate is retained on a 5.00mm BS410 test sieve.
- Thermosetting resin :-A resin that, when hardened, is converted into an essentially infusible and insoluble product .
BS 6319 Part 2: Method for measurement of compressive strength
This Part of BS6319 describes the procedure for the measurement of the compressive strength of specimens of resin based mortars and concretes in the form of cubes. This method is not applicable to unfilled systems.
- Compressive stress (nominal) :- The compressive force (in N/mm2) carried by the test piece per unit area of original cross section.
- Compressive strength :- The maximum stress (in N/mm2) carried by the test piece during a compressive test at the time of failure.
BS 6319 Part 3: Methods for measurement of modulus of elasticity in flexure and flexural strength
This Part of BS6319 describes methods for the measurement of modulus of elasticity in flexure and flexural strength of specimens of polymer based mortars and polymer/cement based mortars in the form of rectangular prisms.
- Elastic modulus :- ratio of stress to corresponding strain below the proportional limit, where the proportional limit is the greatest stress which a material is capable of supporting without any deviation from the proportionality of stress to strain (Hooke’s law)
- Modulus of elasticity in flexure :- elastic modulus determined from the relationship between load and the deflection induced by that load in a simple freely supported beam .
BS 6319 Part 4: Method for measurement of bond strength (slant shear method )
This Part of BS 6319 describes a method of determining the slant shear bond strength of resin bonded prisms representing various composite constructions using the test procedure for compressive strength described in BS6319-2
- a) cracked hydraulic cement concrete repaired by resin injection
- b) hydraulic cement concrete with a resin composition topping or hydraulic cement concrete primed with a resin composition and built-up with a further layer of mortar or concrete
- hardened hydraulic cement concrete bonded to hardened hydraulic cement concrete with a resin composition as, for example, when joining precast concrete units
- Compressive stress (nominal) :- The compressive force (in N/mm2) carried by the test piece (at any time during the compressive test) per unit area of original cross section measured normal to the principal axis.
- Compressive strength :- The maximum stress (in N/mm2) carried by the test piece during a compressive test, at the time of failure.
- Slant shear bond strength :- The compressive strength (in N/mm2) of a scarf-jointed test piece
Part 6: Method for determination of modulus of elasticity in compression :-
This Part of BS6319 describes a method for the determination of the modulus of elasticity in compression of specimens of resin based mortars and concretes in the form of rectangular prisms.
- compressive stress :- the compressive force carried at any time by the test specimen per unit area of the original cross section
- compressive strain :- the ratio of the change in the distance between two reference points along the axis of the test specimen when related to their original spacing .
- elastic modulus :- the ratio of stress to corresponding strain below the proportional limit, where the proportional limit is the greatest stress which a material is capable of supporting without any deviation from proportionality of stress to strain (Hooke’s Law)
- secant modulus :- the ratio of stress to corresponding strain measured relative to a level of pre-stress applied to bed firmly the specimen platens and ball seating. Accordingly, the secant modulus is based on the stress required to extend the gauge length of the test specimen by0.2% from a pre-stress of approximately10% of the expected force at0.002 strain.
BS 6319 Part 7: Method for measurement of tensile strength
This Part of BS6319describes a method for measurement of the tensile strength of resin based mortars and concretes cast in the form of dumb-bell shaped briquette test specimens. This method is not applicable to unfilled systems (see note1), or to materials having fibrous constituents (see note2) or to materials containing a filler that will not pass through a3.35mm test sieve as specified in BS410.
- tensile stress :- the tensile force carried by the test specimen per unit area of the original cross-sectional area of the central portion of the specimen .
- tensile strength :- the maximum tensile stress which the test specimen is capable of supporting.
BS 6319 Part 8: Method for the assessment of resistance to liquids
This Part of BS6319 describes a method for assessing the resistance to liquids of resin based mortars and concrete using the test for flexural strength described inBS6319-3.
The principle of the test is the comparison of the flexural strength of test specimens which have been exposed to chemical reagents under defined conditions with that of control specimens which have not been exposed to the reagents but which were prepared from the same batch of resin composition. Any changes in the mass and appearance of the specimen or test reagent during the test are observed and recorded
BS 6319 Part 9: Method for measurement and classification of peak exotherm temperature
This Part of BS6319 describes a method of measurement for the peak exotherm temperature for resin based materials for use in the construction industry. A general guide-line for the classification of systems as “high, medium or low” exotherm is given inAppendix A
- The principle of this method is the determination of the temperature that a resin composition reaches after mixing the component parts together. The maximum temperature reached under standardized but not adiabatic laboratory conditions is recorded and reported as the peak exotherm temperature.
BS 6319 Part 11: Methods for determination of creep in compression and in tension
This Part of BS6319 describes methods for the determination of the creep of specimens of polymer and polymer/cement mortars. Creep in compression is measured on rectangular prisms and creep in tension on necked specimens having a maximum aggregate size of2.4mm.
The prime objective of the methods is to provide comparative data on materials in order to establish whether or not creep is likely to be significant in the intended application.
The methods provide an estimate of creep strains within – 10% of the absolute value under the particular environmental conditions in which the test is conducted.
For comparative purposes, it is necessary to control the temperature to within – 2 C of the specified temperature but control of humidity is not essential.
- Compressive stress :- force per unit area of the original cross section of a member in compression
- Elastic strain :- deformation produced by a stress up to the elastic limit and expressed as the change per unit of original dimension.
- Elastic compressive strain :- elastic strain measured immediately following the application of compressive load.
- Tensile stress :- force per unit area of the original cross section of a member in tension
- Elastic tensile strain :- elastic strain measured immediately following the application of tensile load.
- Creep strain :- time-dependent strain measured over and above elastic strain under the application of a constant load.
- Creep coefficient :- ratio of creep strain to elastic strain at the same applied stress.
- Elastic recovery strain :- amount of elastic strain lost by a member immediately on unloading to zero stress.
- Creep recovery strain ;- amount of creep strain lost by a member following unloading to zero stress
- Creep recovery coefficient :- ratio of creep recovery strain to elastic recovery strain.
BS 6319 Part 12: Methods for measurement of unrestrained linear shrinkage and coefficient of thermal expansion :-
This Part of BS6319 describes the methods for the measurement of linear shrinkage from initial gel and of the coefficient of thermal expansion of hardened polymer and polymer/cement mortars in the form of unrestrained thin strips (less than20mm in thickness). The methods are suitable for materials that do not contain aggregates larger than3mm used in thin layers for patch repairs and surfacing applications.
4.1 Shrinkage test
A freshly mixed sample of polymer mortar or polymer/cement mortar is placed in a shallow steel trough shaped mould with sliding ends, the inside of which has been treated to prevent adhesion by the mortar. The trough has sliding ends which bond to the mortar and are free to move as the mortar expands or contracts. Linear displacement transducers attached to the ends enable the shrinkage to be measured. A temperature sensor attached to the mould enables its temperature and so that of the mortar to be measured.
Coefficient of thermal expansion :- Samples of hardened polymer mortar or polymer/cement mortar, prepared as for the shrinkage test, are subjected to a number of temperature cycles while movements of the ends and changes in temperature of the mortar are monitored. Correction is made for changes in the length of the mould.