Laboratory Procedure for Rock Binder

Laboratory Procedure

for
S.E.A.M
Sulphur Extender & Asphalt Modifier

Introduction

One real quick way to tell if SEAM is in the mix is to break open the core sample and observer the interior. Do not cut or saw the sample, but break it using a mallet or other instrument with a striking blow.

When SEAM is present the mix appears to have small, glistening diamonds mixed throughout. The more it sparkles, the higher the concentration of SEAM. The typical 60/40 by volume ratios that we use in Las Vegas look like the stars in the heavens at night when we break them. Very beautiful.

The accurate way to test for the ratio is to do a burn off, do a nuke AC content, subtract the latter from the former and voilá: SEAM content.

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Testing begins with submittals of the appropriate job mix formula, aggregate samples and binder materials, SEAM for extending and modifying the bitumen. The Marshall Method, described herein, is used to evaluate compaction, strength and flow. Volumetric properties are determined according to AASHTO procedures. The following description and data are included for informational purposes.

Procedure

The aggregate is batched according to a mix design specifications and prepared in a Hobart Model C-100 mixer with a pre-heated wire whip and pre-warmed bowl, or a similar apparatus. Aggregate is heated to a temperature of not more than 335° F.

Rock Binders SEAM arrives in pellet form and requires no pre-heating.

SEAM is used by determining the ratio to use (typically a 70/30%, 60/40%, 50/50% ladder is done). The normal substitution, learned from field experience, is 30-50% by volume. SEAM has a higher sp.gr. (of 1.968) than asphalt (1.02). Therefore when extending your oil add 1.5 parts SEAM to 1 part asphalt by weight to achieve the same volume.* With proper design, up to 50% can be substituted for obtaining higher strength pavements.**

* Justification for Using a SEAM Substitution Ratio (R) Between 1.5 and 2.0.

** Always add asphalt oil first then the SEAM pellets to the 325° F aggregate. Usually full coating is achieved within 30 seconds and the mixture is cooled to around 285° F. by the mixing and addition of ambient temperature SEAM.

At this point, the mixture is split into samples and poured into warmed Marshall specimen molds. The dividing process cools the mixture temporarily to 230° - 250° F. Specimens are then heated in an oven at 280° F. for 30 minutes. Make certain your oven is well ventilated.

Next, Marshall compaction is performed with heated cylinders to prevent "bond breaking" on the outer surfaces due to rapid cooling. Specimens are struck 50 blows per side for standard roadways and 75 blows for heavy duty pavements.

A duplicate set of specimens can be held for 10 days to check Marshall properties since the strength numbers show a dramatic increase over this period. Typical results show higher stabilities after 10 days which may continue to increase slowly for up to one year. Microscopic crystallite structuring increases internal bonds, strengthening the pavement from within.

* Notes:

Rock Binders SEAM is generally used as an extender or substitute for up to 50% of liquid asphalt binder. Years of field experience show that 30% to 40% are typical substitutions and 50% is for the greatest strength gain. REMEMBER THAT SEAM WEIGHS MORE THAN ASPHALT. USE 1.5 TO 1 WHEN SUBSTITUTING, SO THE VOLUME (HENCE THE AGGREGATE COATING) WILL BE THE SAME.

Hydrated lime, Ca(OH)2, an anti-stripping agent, should never be used with SEAM nor ARP as it could cause the formation of salts that may be hydrophilic.

SEAM is competitively priced with conventional asphalt, even when a 150%, by weight, substitution ratio is required.

Rock Binders SEAM requires a minimum of 30% by weight to achieve rut-resistance benefits.

Marshall Stability lbs. 60/40 ratio = 4000 min. @ 75 blow, both sides preferred. 70/30 ratio = 3000 min. @ 75 blow, both sides preferred.

Hveem Stability lbs. @ 140° F min. / 60° C. - 60/40 ratio = 45 min. 70/30 ratio = 40 min. *Hveem compaction must be run at higher temp (typically 250° F to 260° F) than regular AC due to set point of SEAM.