Aggregate Testing

About this Project

The 5.2-million-metric-ton-per-year Angola LNG processing plant is the onshore portion of a broad program to commercialize gas reserves for domestic use and export. The plant will help fuel industrial power generation and an expanding petrochemicals industry in the Congo River delta. In addition, commercializing Angola’s gas reserves helps increase employment. It provides feedstock for industrial power generation and an expanding petrochemicals industry.

At the inception of the construction of the $12.0 billion LNG plant in Angola, C3S was contracted as one of the subcontractors to evaluate sources of local aggregate through aggregate testing in Angola for the project and monitor the quality of Portland cement imported from China for the project.

The plant infrastructure includes storage tanks for LNG, propane, butane and condensate and an LNG loading jetty able to accommodate vessels up to 315m in length.

Several rock deposits in Angola were quarried by a Houston geotechnical firm and samples delivered to C3S for evaluation. Other sources of aggregate from other locations in the country were sent for aggregate testing and quality control tests, principally among them, LA Abrasion test, potential for Alkali-silica reactivity (ASR) and a host of ASTM tests.

The following tests featured prominently in most of the aggregate testing performed.

ASTM C-29 “Bulk Density Test”
ASTM C-40 “Organic Impurities”
ASTM C-88 “Soundness of Aggregates by Use of Magnesium Sulfate”
ASTM C-117 “Materials finer than No. 200 Sieve”
ASTM C-123 “Lightweight particles in Aggregates” –
ASTM C-131 “LA Abrasion test for Small Size Coarse Aggregate”
ASTM C-136 “Sieve Analysis”
ASTM C-142 “Clay Lumps and Friable Particles in Aggregate”
ASTM C-289 “Potential ASR of Aggregates (Chemical Method)”
ASTM C-295 “Petrographic Examination of Aggregates for Concrete”
ASTM C-1260 “Potential ASR of Aggregates (Mortar bar Method)”

Note – This featured project report is an abbreviated version of the actual report prepared for the client.

Samples

Samples tested for suitability as a construction material, including a potential threat of Alkali-silica reactivity (ASR).

Rocks evaluated by petrographic analysis

Aggregate Testing

Other aggregate testing performed for infrastructural work in other countries include:

(1) Aggregates from Douala and Bioko quarries in Equatorial Guinea, West Africa.

(2) Aggregates: Ammari 8/15, El Moustakbal 8/15, Satrech 8/15, El Moustakbal 15/25 Satrech 15/25, were evaluated for a project in Algeria.

(3) Rocks from Delores Mine in Mexico were evaluated for an investor seeking to generate aggregates for construction projects in Southwest USA.

(4) Evaluation of Rock samples from St. Vincent for Coastline Protection Armour Rock in Trinidad & Tobago. Jaggersaar Agency W. Ltd., Penal, Trinidad & Tobago.

(5) Aggregates from locations in Trinidad for in-country infrastructural projects. Trintoplan Consultants, Tacarigua, Trinidad & Tobago.

Summary for one of the tests is succinctly summarized below.

EXECUTIVE SUMMARY

Five- (5) coarse limestone aggregate samples from Angola were submitted to our laboratory, on October 17, 2005, for a limited number of tests. The tests are:

• C-131 Resistance to Degradation, LA Abrasion Test
• C-88 Soundness Test by Magnesium Sulfate
• C-136 Sieve Analysis
• C-142 Clay Lumps & Friable Particles
• C-289 Potential Alkali-Silica Reactivity (Chemical Method)
• C-295 Petrographic Examination of Aggregates

The samples were labeled as follows:

1. 1.  Taxiera Duarte
   2. Techno Angola
   3. Paviterra
   4. Afritrack
   5. Sourte De Costa

The first test, degradation by Los Angeles Abrasion Test, eliminated Paviterra sample from the additional tests. Based on results of the additional tests, three of them, namely: Taxiera Duarte, Techno Angola, and Afritrack are suitable as aggregates for concrete.

Sourte De Costa was disqualified based on not meeting the requirements of the soundness test by the magnesium sulfate test.