Civil & Environmental EngineeringCivil & Environmental Engineering

Evaluation of Hybrid Slurry Resulting from the Introduction of Additives to Mineral Slurry

FDOT Construction Conference

Presented by: Sastry Putcha, P.E.

Project Overview

The mechanism by which mineral and polymer slurries perform is quite different

With the use of a hybrid slurry that shares traits from both mineral and polymer it is unclear on which set of specifications should be applied

Project Tasks

Assess performance of hybrid slurry products as it pertains to state specifications

Develop a baseline to which hybrid slurry combinations will be compared

Review current slurry specifications relative to API Filter Press Testing

Establish criteria for hybrid materials

Slurry Products

Additive Products

Slurry Testing

Viscosity Density API Filter Press

(infiltration rate) Sand Content pH

Testing Apparatus

API Filter Press Specifications indicated

to use dead weight / plunger system to achieve a constant 100 psi pressure

100 psi never achieved, used in-house air system at a reliable 80 psi

Testing Apparatus

Density 1000 mL volumetric flask

and a digital scale used to obtain accurate density measurements

Testing Apparatus

Viscosity Marsh funnel used to fill

a smaller cross section container that provides consistent results between experimentalists

Slurry density results

State Spec 64 - 73pcf

Slurry viscosity results

State Spec 28 – 40s/qt

API filter press flow rate versus viscosity (excluding attapulgite)

State Spec 28 – 40s/qt

API filter press flow rate versus density (excluding attapulgite)

State Spec 64 – 73pcf

Required Wyo-Vis DP

0

0.05

0.1

0.15

0.2

0.25

0.3

0 10 20 30 40 50 60

Pure Gold Mix Ratio (lb dry powder/100 gal)

Addi

tive

Requ

ired

(lb/1

00 g

al)

30 s/qt35 s/qt40 s/qt

0.03

Settling Column Tests

Viscosity Density Sand Content at

various depths pH Temperature Sand Fallout Rate

(accumulation on bottom of shaft)

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

0 5 10 15 20 25

Sand Content (%)

Dept

h (ft

)0 min 15 min30 min 60 min120 min 240 min1440 min

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

0 5 10 15 20 25

Sand Content (%)

Dept

h (ft

)

0 min 15 min30 min 60 min120 min 240 min

Ongoing / Future Work

Sand Settling rates for polymer fortified / hybrid slurry

Test additional additives Establish sand content limits for hybrid

slurries