Project Planning Phase

We assist our clients in various aspects of concrete analysis, sourcing and qualifying during their projects planning stages.

Our focus is to maximize the lifespan of your project.

We determine which materials are best for your structure. We place special consideration on sources, consistency of material, and overall durability. For capital projects we ensure materials are compliant to the project’s specifications and durability requirements.

Cement

CEMENT

C3S helps its clients to evaluate cement on capital projects for compliance to project specifications and durability requirements.

Why is Cement Evaluation Critical on Capital Projects?

File photo from a project of three (3) year old water tank. Analysis revealed wrong choice of cement and high water cement ratio led to formation of expansive Ettringite in concrete.

File photo from a project involving breakage of concrete coating over metal pipe. Analysis Revealed Wrong choice of cement and high void content in concrete led to failure.

With Project Planning Phase, we aim to build the quality of concrete ingredients upfront into the client’s project to improve the life of structures and be able to reduce the maintenance costs.

Forensic Investigation of Mortar at a School Building under Construction

During construction, portions of the tiles that was recently installed started falling off.

After we performed a petrographic analysis of the mortar sample we figured out that high entrained air content and high pozzolanic material content had compromised the binding capability of the mortar to bind tiles to the wall.

Our evaluation identified the cause of the problem which necessitated a change of product for the remainder of the work.

Part of the front view of the School under construction.

Tiles from a section of the building was removed and to be replaced with a durable binder.

Shows excessive entrained air which tends to lower the binding capability of mortars to substrates.

 

A micrograph showing a high proportion of pozzolanic material – a contributor to low binding capability of mortars to substrates.

Aggregates

Aggregates

aggregates main

C3S helps its clients to evaluate cement on capital projects for compliance to project specifications and durability requirements.

Why is Aggregate Evaluation Critical on Capital Projects?

Aggregates C3S samples Aggregates C3S samples Aggregates C3S samples
Scope: To determine whether the three rock boulders to be beneficiated into aggregates are suitable for use as construction material, specifically, that it will not pose a threat of alkali-silica reaction, ASR, in concrete.

Picture above shows cracks through the aggregate in one of the samples sent to us.

Scope: To evaluate two samples of coarse aggregate and fine aggregate weighing about 10 Kg. each from Fordyce Sand & Gravel Pit near Victoria, Texas for petrographic examination as per ASTM C295 “Standard Guide for Petrographic Examination of Aggregates for Concrete.”

Picture above shows larger fractions of fine aggregate with some mingled with oxides of iron.

Scope: To determine whether the six subject sample specimens are suitable for use as construction material – to be used as aggregate in concrete.

Picture above shows a representative section of Ammari 15/25 aggregate sample.

Evaluated section of a Toll road after eight years in operation to determine the cause of cracks. Cracks were attributed to ASR.

Aggregates Aggregates

Highway pavement cracking due to alkali-silica reactivity, (ASR)

Highway pavement cracking due to alkali-silica reactivity, (ASR)

Aggregates Aggregates

A siliceous aggregate in a high alkali medium showing the reactive gel.

A flowing  gel in concrete with the right conditions of formation, namely: i) reactive aggregate ii) high alkali medium & iii) moisture

Mineral Admixtures

MINERAL ADMIXTURE

Choice of mineral admixture (i) – to optimize concrete placement in varying weather conditions, and (ii) improve durability of hardened concrete. Examples of damage to structure due to contribution by mineral aggregate used.

Mineral Admixture Contribution to Pavement defect

A section of a major highway between two major cities in Texas experienced surface defects about two years after completion. A three mile stretch had to be replaced. Samples evaluated in connection with the problem pointed to a high dosage of mineral admixture used in the affected section of the pavement.

Mineral Admixtures
Mineral Admixtures Mineral Admixtures

Chemical Admixture

CHEMICAL ADMIXTURES

Examples of entrained air content, mostly for long term durability of concrete, in freeze-thaw regions can adversely affect compressive strength of the concrete if in excess.

If entrained air content is below the specified amount it raises long term durability concerns and in some instances affected sections of the structure may have to be replaced.

Chemical AdmixturesInadvertent dosage of air entraining agent – a high air content -caused a loss in compressive strength in a concrete manufacturing plant operation.

(Blue, round circles are entrained air in a petrographic evaluation) 

Chemical AdmixturesLess than specified entrained air content for a section of a bridge deck in Vermont caused the affected section to be replaced due to long term durability considerations.

(Scanty blue round circles are entrained air in the concrete)

Experience Matters

  • Studied cement production technology as a discipline – know cement.
  • Have performed several physical tests and microscopic evaluations of rocks and sands.
  • Can identify potentially deleterious aggregates
  • Understand the role of mineral admixtures – evaluated fly ashes from several power plants in the US.
  • Conversant with all pertinent tests to qualify concrete formulation for a capital or small sensitive project.