Category: Concrete mixture optimization

A concrete sample cut, grinded, polished, and tinted in the laboratory is mounted on a moving X-Y-Z stage positioned below a video camera. The RapidAir control unit automatically moves the stage, and the software determines the portion of the total traverse length that passes through the white air voids. The measurement is done within 12 min for linear traverse analysis and within 30 min for modified point count.
After the scan is completed, the air-void parameters are calculated as per ASTM C457 or EN 480-11. In addition, graphical presentation of the air-void distribution and the raw data are available.

Air-Void system Image.

• Determine the total air content, spacing factor, and specific surface in hardened concrete.
• Effectively and rapidly study and quantify the air void system: volume, spacing, and size distribution of the air bubbles.

Air-Void system Image.

• X,Y,Z-stage with electronic stepper motor for accurate X-Y displacement, 230/120 VAC, equipped with emergency switch
• LED ring lightening system
• Color digital camera, 2 µm resolution
• Microscope objective for op to 100x magnification
• Windows based software with user friendly interface
• Self-calibration with a reference sample
• Exporting of data to MS Excel
• Pint out reports for ASTM C 457 and EN 480-11.

Air-Void system Image. 

RapidAir Ordering Numbers

• Technical data-sheet 
• Publications

• More documentation is available upon request

• ASTM C457, “Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete.”
• EN 480-11, “Admixtures for concrete, mortar and grout – Test methods – Part 11: Determination of air void characteristics in hardened concrete.”

The Auto-Shrink digital dilatometer is designed for linear measurement of autogenous shrinkage (reduction in volume) in hardening cement-based paste or mortar cured under sealed conditions. A special corrugated plastic mold is used to prevent moisture loss and allow the specimen to shrink freely. With Auto-Shrink, it is possible to measure the time dependent deformation of different specimens simultaneously over periods of weeks or even years. Autogenous shrinkage test.

The dilatometer is composed basically of a rigid frame or bench made of Invar, a special steel alloy with a very low coefficient of thermal expansion at room temperature; a high precision digital dial gauge with remote control and reference bar made of Invar as well.

As an option, a dedicated USB input cable and software can be added to connect the gauge to a computer for automatic data-logging. The software allows to read gauges from multiple dilatometers. 

• Quality control of low shrinkage designed mortars, grouts or concrete mixtures
• Research and development
• Assessment of autogenous shrinkage as cause of microcracking

• Support frame and reference bar made of Invar steel alloy
• Absolute type linear encoder Digital Gauge with large, easy-to-read LCD rotating display
• Measuring range: 12.7 mm
• Resolution: 0.001 mm
• Accuracy at 20^oC: 003 mm
• Repeatability at 20^oC: 002 mm
• 8 mm stem with a 1.5 mm spherical tip (carbide tipped)
• Battery life: ≈ 7,000 hours of continuous use
• Service temperature range: 0 to 40°C
• Storage temperature range: 0 to 60°C

Auto-Shrink AS-1000 Kit

Includes:

Optional items for automatic data-logging

Cosumables

• Technical data-sheet 
• Publications

• ASTM C1698, Test Method for Autogenous Strain of Cement Paste and Mortar

The ICAR Plus is designed to characterize the static yield stress, the dynamic yield stress and plastic viscosity of the concrete. A high static yield stress is desirable because it reduces formwork pressure and increases the resistance to segregation. But for ease of pumping, placement and self-consolidation, a low dynamic yield stress is necessary. The dynamic viscosity provides cohesiveness and reduces segregation when concrete is flowing. Thus, by determining the dynamic flow curves of concretes mixtures and optimum balance between ease of flow and resistance to segregation can be realized. These types of determinations cannot be done using conventional slump-based tests. 

The ICAR Plus is composed of a container to hold the fresh concrete, a driver head supported on a frame with an electric motor and torque meter, a four-blade vane and a laptop computer to operate, record the torque  and calculate the flow curve parameters. The size of the container and vane are selected based on the nominal maximum size of the aggregate. A multiple blade “Carrousel” vane is also available for a container for maximum aggregate size of 13 mm for more accurate and stable measurements on materials like high flow self-consolidating concrete (e.g. slump flow > 600 mm), flowable mortars or grouts (e.g. self-leveling), mortars for 3D printing, etc.

Two types of tests are performed: stress growth test at a constant slow speed where the maximum torque measured is used to calculate the static yield stress; and the flow curve test to determine the dynamic yield stress and the plastic viscosity (Bingham parameters).

Concrete Rheometer.

• Research and development to characterize the influence of new materials on concrete rheology
• Optimizing mixture proportions so that the resulting concrete flows readily but is resistant to segregation (especially important for self-consolidating concrete or pumped concrete)
• On-site quality control of mixtures

• Minimum slump: The concrete has to have a slump greater than 75 mm,
otherwise, the concrete is too stiff for being tested
• Nominal maximum size of aggregate (NMSA): up to 32 mm
for the largest available container
• Vane rotation speed: 0.001 to 0.667 rev/s
• Motor type: Integrated Servo Motor
• Accuracy: ±0.1 %
• Resolution: 0.001 Nm
• Minimum Torque: 0.01 Nm
• Peak Torque: 90 Nm for not more than 2 seconds
• Continuous Maximum Torque: 32 Nm
• Power Supply: Input of 100-240 VAC 50-60 Hz – 3.5A.
• Digital Calibration can be performed by user at any time
• Performs static stress growth and dynamic flow curve tests
• Software computes static yield stress, dynamic yield
stress, and plastic viscosity in fundamental units
• Motor drive dimensions: 11 x 11 x 43 cm
• Motor console weight: 7.5 kg
• Carrying Case dimensions: 67 x 52 x 28 cm
• Carrying Case weight: 20 kg, including motor drive, base
frame, vane, power supply and cables

RHM-4000 ICAR Plus Kit

Includes:

To be ordered separately

1. Available containers and vanes for different NMSA

*Default size supplied along with the RM-4000 ICAR Plus Kit if another size is not specified.

• Technical datasheet

• Publications

No standards available.

The AVA-3000 allows rapid measurement of the key parameters that characterize the air-void system in fresh concrete before or during its placement. This permits better quality control and optimization of concrete performance when exposed to cyclic freezing and thawing.

A mortar sample of the air-entrained concrete is obtained from the fresh concrete with a sampling tool and injected into the blue AVA release liquid at the bottom of a riser column with water above.

The mortar sample is stirred gently into the release liquid by which the air bubbles are released and start rising through the water following Stoke’s Law: larger bubbles will rise faster than smaller bubbles. At the top of the riser column, a buoyancy pan attached to a high-precision balance measures the change in the pan’s weight caused by the rise of the air bubbles. Those changes are continuously collected over the 25-minute test and the software analyzes the information to compute the size distribution of the bubbles, the specific surface and the spacing factor.

Air-Void system in concrete.

• For rapid quality control and in-situ quality assurance testing of freeze-thaw resistant concrete
• For research purposes where knowing the size distribution of the entrained air bubbles is relevant
• For establishing relationships to durability determined by freeze-thaw tests, e.g., ASTM C666-15

• USB interface
• Measuring time = 25 min./test
• Sample size for a test = 20 mL
• Real time data acquisition (weight vs time) showed on screen
• Reports voids’ curve of size distribution and histogram for void size < 2 mm
• Algorithm calculates spacing factor and surface area in relation to ASTM C457
• Operational voltage 240 V AC
• Weight: 13.8 kg (bath tank) and 7.8 kg (base unit)
• Dimensions: 40 x 40 x 30 cm (bath tank) and 47 x 48 x 21 cm (base unit)
• Mini balance: 300 g capacity, 0.01 g resolution (0.001 g internal accuracy)
• Magnetic stirrer: 150 mNm, 4000 rpm
• 35 L bath tank with de-aerating pump and heater

AVA-3000

The AVA-3000 is delivered in two cases:

1. Aluminum case with base unit and accessories.

Item	Order #
Alumina case with pouch and foam insert	AVA-3005
Base Unit	AVA-3010
Riser Column	AVA-3020
Windshield	AVA-3022
6 mm Screws, 2 pcs	AVA-3025
Stirrer Pin, with one spare	AVA-3028
Piston	AVA-3030
Buoyancy Pan	AVA-3040
Wire Cage	AVA-3050
Vibrator	AVA-3060
Funnel	AVA-3080
Graduated Sampling Syringes, 3 pcs	AVA-3090
Brush	AVA-3130
Template with center hole	AVA-3140
USB Cord	AVA-3160
Power Cable, 110VAC  or  220VAC	AVA-3170
Rubber Suction Ball	AVA-3180
Vaseline, can	AVA-3190
Vaseline, Tube	AVA-3200
CD with AVA Literature	AVA-3210
AVA-3000 software CD	AVA-3220
AVA-3000 Manual	AVA-3230
Flashlight	AVA-3250

2. Aluminum case with water tank for de-aerating and tempering, laptop and drill machine

Item	Order #
Alumina case with foam insert	AVA-3300
Water tank with temperature regulator and stirring	AVA-3310
Power cable, 110 V or 210 V	AVA-3315
Top Lids, 2 pcs	AVA-3320
2L Containers for release liquid, 2 pcs	AVA-3330
Laptop with installed software	AVA-3340
Electric Drill, 110 V or 210 V	AVA-3350

To be ordered separately

• Technical data-sheet 
• AVA slides
• Publications

More documentation is available upon request.

• ASTM C457-16.  “Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete”.

• EN 480-11.  “Admixtures for concrete, mortar and grout – Test methods – Part 11: Determination of air void characteristics in hardened concrete”.

• ASTM C666-15. Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing.