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through the use of closed containers, decreased partial oxygen pressure,etc.Furthermore, for enhanced repeatability, only one specific solvent should beprescribed in South Africa. It is the authors' recommendation thattoluene/ethanol should be considered for South African conditions, basedon:• The acceptable technical performance of this solvent combination asseen in the literature review (Chapter 2.1.4);• The low health and safety risks associated with these solvents(Appendix C).Alternatively, nPB, may be considered as the national standard solventbased on the fact that, internationally, the trend seems to be in thisdirection. However, the more recent health alert (Appendix A) is of concern.It is also recommended that one single recovery/distillation procedure beprescribed for South Africa. Possible choices include the SUPERPAVEdevelopedmethod as described in AASHTO T319, or alternatively, ASTMD5404 (rotary evaporator method), but amended to include a two-flasksystem for lower binder hardening.Based on international experience as reported in the literature 9 ,itisimportant to note that should a specific solvent be chosen as a nationalstandard for the recovery of binders, it would be necessary to subject thatsolvent to a full investigative procedure, in order to verify the technicalperformance of that solvent. The investigative procedure should include:• The recovery of a number of binders of known properties fromdifferent refineries (prior to mixing), as well as a number ofpolymer-modified binders of known properties, using the proposedsolvent in conjunction with reference solvents such as benzene andTCE. This would establish the technical performance of the proposedsolvent in the absence of any aggregate effects. It is recommendedthat un-aged binder as well as long-term aged binder be used todetermine the effects of binder ageing on the recovery process;• A repeat of the process above, but using relatively older pavementsamples encompassing at least six of the more common aggregatetypes and at least one aggregate predicted to give problems (e.g.30
absorptive limestone). In this way aggregate effects can beestablished. For comparisons, pyridine can be used to establish the''true'' binder content of the mixes;• The identification of those test values obtained from the recoveredbinders that would best reflect the performance characteristics of thebinder prior to recovery (performance characteristics such asstiffness, elasticity, adhesion/cohesion). Internationally there is atendency to use the test values obtained from the dynamic shearrheometer to reflect the stiffness of the binder prior to recovery.Historically, the coefficients of variation for these test values havebeen high, and it may be that some other test value, with a lowercoefficient of variation, would be more useful as the primary indicatorfor defining the properties of the recovered binder;• The determination of the effect of background lighting and timeconstraints at the various stages of extraction/recovery.Irrespective of the processes that would be followed, it is vital that sufficientexperimental repetitions be carried out to establish the statisticalrepeatability with confidence. The repeatability would have a direct effect onthe quality of the conclusions drawn from the work.In conclusion, the authors believe that the current status quo in SouthAfrica with regards to the determination of binder content, as well as to therecovery of binders cannot be maintained. South Africa is trailing Europeand the USA in the formulation of a cohesive national binder recoveryphilosophy, and the necessary investigative data is inadequate to show thatour current test methods and practices:• have been validated;• are acceptable with regards to the coefficient of variation; and• involve properties chosen to characterise the binder that reflect thebinder performance correctly.In the absence of such evidence, published journal articles from SouthAfrica that involve recovered binder properties may yield findings andconclusions based on data that has not been statistically validated.31
Page 1: Guide to the safe handling ofsolven
Page 4 and 5: Sabita DVD SeriesDVD100DVD200DVD300
Page 6 and 7: CONTENTS1. Introduction2. Solvent s
Page 8 and 9: • The use of High Performance Liq
Page 10 and 11: 2. Solvent specific test methods2.1
Page 12 and 13: • A mass balance requires a tempe
Page 14 and 15: *Jojoba oil (pronounced “ho-HO-ba
Page 16 and 17: properties of the recovered binder.
Page 18 and 19: Table 1. Coefficients of variationM
Page 20 and 21: • Temperature - Although binder h
Page 23 and 24: • Density - In general, a solvent
Page 25 and 26: 2.5. The determination of the softe
Page 27 and 28: 4. Evaluating the cost-effectivenes
Page 29: 6. Conclusions and recommendationsT
Page 33 and 34: 13. Peterson, GD, Davison, RR, Glov
Page 35 and 36: in a location close to where the pr
Page 37 and 38: product identifier (product name);
Page 39 and 40: eye wash bottles and safety showers
Page 41 and 42: • reaction to naturally-occurring
Page 43 and 44: consulting the MSDS for the product
Page 45 and 46: those which could compromise an ind
Page 47 and 48: • Reactive chemicals May be sensi
Page 49 and 50: The following guidelines should be
Page 51 and 52: mercury air concentrations. If a la
Page 53 and 54: Be prepared to repeat the process i
Page 55 and 56: Leaking regulators, cylinder valves
Page 57 and 58: Peroxide-forming (e.g. ether) and e
Page 59 and 60: • Direct connections: Direct conn
Page 61 and 62: This guide is available on the UK H
Page 63 and 64: Factors that can increase the risk
Page 65 and 66: containers that may be contaminated
Page 67 and 68: Record each run in a logbook: keep
Page 69 and 70: • Gas chromatographs (GC): Gas ch
Page 71 and 72: Locate and know how to test and ope
Page 73 and 74: Do not remove a dressing that has b
Page 75 and 76: As soon as the flames are extinguis
Page 77 and 78: Appendix B - Recommendations for so
Page 79 and 80: • All packages in storage should
Page 81 and 82:
Table 2.Examples of incompatible co
Page 83 and 84:
Table 3. Suggested segregation for
Page 85 and 86:
• Keep picric acid solutions wet
Page 87 and 88:
peroxides. The radius shall be meas
Page 89 and 90:
acute health effect - an effect tha
Page 91 and 92:
8 Corrosive; 9 Miscellaneous.ED50 (
Page 93 and 94:
freezing point - the temperature at
Page 95 and 96:
airborne substance, averaged over a
Page 97 and 98:
teratogen - chemical which may caus
Page 99 and 100:
• Many of the occupation exposure
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