(J11;Strength1) COMPREHENSIVE in place STRENGHT TEST

The Windsor HP Probe™ system rapidly and accurately determines the concrete compressive strength of a structure by driving a probe into the concrete with a known amount of force. Improved and enhanced over thirty years, this modern system is capable of measuring concrete with a maximum compressive strength of 17,000 PSI (110MPA). It has been ruggedized for use in the construction environment, yet refined to provide the user with a simpler system to operate. An electronic measuring unit has been added to help ensure proper test results which can be recorded for later review or uploading to a personal computer.

Two probe styles are available: one for lightweight, low density concrete with airfilled aggregate and the other probe for more standard mix designs. Also, two standard power settings facilitate testing fresh concrete as well as mature mixes.

Approved by municipalities in the United States, Asia, and Europe, this system conforms to ASTM C-803, BS 1881 and other testing standards.

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Features & Benefits:

	New electronic measuring system enhances accuracy and efficiency
	Measurement to 17000 psi (110 MPa)
	Memory for data storage and uploading to PC
	Safe: no accidental discharge and no recoil
	Fast and economical use
	Determines the developing strength of concrete; improves safety, ensures quality and reduces costs
	Monitors the strength for rehabilitation as concrete ages
	Conforms to ASTM C-803 and other official tests

SAFE & USER FRIENDLY

The Windsor HP System does not require great skill to use and consistent results can be obtained by construction site supervisory staff or field technicians. In fact, among its users are contractors, engineers, architects, testing laboratories, ready mix concrete producers, owners, managers and government authorities. This system has widespread use in testing concrete in-situ, on conventionally placed, sprayed or precast concrete; on horizontal or vertical slabs; on floors or overhead; on fresh or mature concrete.

The system is safe to use. The driver cannot be discharged unless it is fully depressed with some force against the actuating template which rests against the surface being examined.

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PROBES
There are two power settings available, low and standard power. The low power is used where concrete strength is less than 3000 psi (19.4 MPa). The newly designed silver probes can be used for high performance concrete with strength up to 17000 psi (110 MPa). The probes are made of a high strength alloy, specially heat treated and annealed to achieve a hardness of Rockwell C 48.Special machining of each probe eliminates stress concentrations.

The gold probe has a 56% greater cross-sectional area than the silver; it is recommended for light weight concrete - less than 125 lbs/cu. ft. (2003 Kg/M3) in density. The silver probe is used with concrete having a density greater than 125 lbs/cu. ft. (2003 Kg/M3).

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PROCEDURE;
A. Actuating
Load the driver with a power load and probe suited for the type of concrete being examined. Place the driver firmly on the actuating template and fire. The locating template is then used to locate the probes at the corners of a fixed triangle. Normally, three measurements are required for consistent and statistically reliable results.

B. Measuring
The electronic measuring device is menu driven and programmed for selection according to the following parameters.

• Aggregate hardness
• Light weight, normal, or HP concrete
• American or Metric units

The three individual tests are automatically averaged and displayed on the LCD in accordance with ASTM procedure. This data together with time and date of the test are stored in the memory for subsequent uploading to a PC. An extractor is supplied to facilitate probe removal after the test.

The Standard Windsor Probe™ System includes a depth gauge and “Strength Chart” for determining the concrete strength.

This is an economical alternative for many concrete test environments.

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TECHNICAL;
The Windsor HP Probe™ System is designed to evaluate the compressive strength of concrete in place. It is non-destructive and can be used with equal effectiveness on fresh and mature concrete. Equally accurate results are obtained on horizontal or vertical surfaces provided that the probe is perpendicular or at right angles to the test surface.

A hardened steel alloy probe is propelled at high speed by an exactly measured explosive charge into the concrete and its penetration measured. Each power load is guaranteed to have an energy level to give an exit muzzle velocity tolerance within ±3%. The compressive strength of the concrete is directly related to the resistance to penetration of the crushed aggregate and cement matrix: this is determined by the distance required to absorb the specific amount of kinetic energy of the probe. The compressive strength of the concrete is empirically related to the penetration that varies with the hardness of the aggregate. This relationship is recognized by determining the Moh’s scale of hardness of the aggregate and applying a correction factor to the penetration.

The combined contributions of both the aggregate and the cement paste to concrete strength are examined by the test. The accuracy of the inferred strengths has been examined in many independent tests and trials. The Windsor HP results correlate well with the concrete strength determinations obtained by conventional means.

For most accurate test results ASTM recommendso that a correlation be developed for the particular mix design being tested. Exact duplication of cylinder test results should not be expected. The probes measure the strength of the actual concrete in a structure rather than that of a sample compacted and cured under strict and somewhat artificial conditions which do not necessarily represent those of the structure itself.

The Windsor Probe™ test has been approved by federal, state and municipal agencies as well as a number of foreign countries. It conforms to the following tests, specifications and practices:

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         Instructions

1. READ THIS MANUAL THOROUGHLY

No one - not even an experienced testing technician or engineer - should attempt to use the Windsor Probe™ Test System before reading this instruction manual. Careful study of the instructions on the following pages for the handling and maintenance of the tool and gages will provide a basic understanding of the system’s operating principles.

        

For thorough understanding of Windsor Probe™ operation, and for certification as an approved operator, it is necessary to study this instruction book and other literature enclosed with the system.

         

The manufacturer disclaims responsibility for incidents which may result from the disregard of the operating instructions. The user must follow these instructions exactly in order to obtain accurate results. Failure to do so may yield results which do not accurately reflect the true strength of the concrete tested.

               

1. INTRODUCTION
   The Windsor Probe™ System tests concrete strength by driving a steel probe into the surface of concrete with a precisely governed explosive charge. The shallower the depth of probe penetration, the stronger the concrete. For more information and data substantiating the accuracy of the Windsor Probe™ Test System contact Windsor Systems, Inc. at 800-426-6500 or your distributor.
   
                

Warning: Although the driver unit has an internal safety mechanism that resists discharge except when in place and ready for testing, always treat the driver unit with the same respect as a loaded gun, whether loaded or not. Never point it at anything other than the surface to be tested, and never touch the trigger unless you are driving a probe.

          

NEVER drive a probe without wearing eye and ear protection. The steel probe enters the concrete at a very high energy level which can sometimes cause spalling and flying aggregate and concrete.

        

The driver unit should not be used in any explosive atmosphere.

          

1. TESTING CONCRETE
   The system will accurately test concrete in virtually any structure, and can be used on either flat or curved surfaces. To evaluate structures that have a flat surface, probes are placed in groups of three using the triangular probe-locating template. To evaluate structures that have a curved surface, three probes are placed individually using the single probe-locating template.
   
               

3.1 Where To Test: Generally, the engineer specifies where to test concrete in a structure or product. However, since concrete strength can never be uniform throughout in its permanent structural environment (ACI-214), certain fundamental guidelines govern the location of tests.

         

FOR EXAMPLE:

• The lowest strength concrete will be found in the top third of a column, flat or suspended slab, or even a molded test cylinder.
• When testing suspended slabs for form or shore removal, test the top side. This is the compression side in the structural element.
• To determine strength adequacy for stressing post-tension strands, test near bulkheads and approximate center of the member.
• Columns or walls should be tested near the top, center, and bottom. The result is usually stated as an average.

Note: A high percentage of forming systems require that the in-place concrete strength shall have achieved in excess of 2500 psi before form removal. However, the engineer should specify the strength requirement. Most post-tension systems for stressing or pre-stressing for products require 70% of the design strength for stressing or release. But, again, the engineer should specify the values.

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Frequently Asked Questions