DEFINITION
Gunite as herein specified is a trade name for dry process Shotcrete used to designate a mixture of Portland Type 1 cement and sand aggregate thoroughly mixed dry, passed through a gunite machine, and conveyed by air through a flexible hose, hydrated at a nozzle at the end of such flexible hose and deposited by high-velocity air pressure in its place of final repose.

PROPORTIONS
Unless otherwise specified, all dry process shotcrete (aka gunite) shall be mixed at the minimum in the proportions of 1:4 parts ratio based on dry loose volume and down to 1: 3.5 parts ratio based on dry loose volume after shot. Our truck's mix design has been verified by Terracon Consulting to mix and produce gunite (after pneumatically applied and proper curring) with PSI strength ranging from 4000+/- to 5000+/- PSI after 28 days and with a 38-day break. 

Otherwise stated, the minimum average compressive strength of gunite should be at an average of 2,500 P.S.I/ 17.24 MPa after 28 days of the gunite shoot. Gunite strength will equal or exceed 85% (2125 P.S.I.) of the design strength with and not less than 75% (1875 P.S.I) after 28 days.

Wet Curing must follow ACI 308 and be continuous for a period of a minimum of 14 days (though we highly recommend 28 days). This is vital to the overall strength of the product and is the responsibility of the pool builder and or homeowner.

These are the standards set by ACI - (American Concrete Institute) 350, 506, 308, 207. These are also reinforced by PHTA (Pool and Hot Tub Alliance)    
 

MATERIALS

CEMENT
Only Portland cement of American manufacture complying with the current issue of “Standard Specifications for Portland Cement,” A.S.T.M. C-150-67 shall be used. Type I Portland cement shall be used unless specified in the detailed specifications. Cement is purchased from Texas Lehigh Cement and transported from a third-party vendor or by in-house transport and is not produced by Texan Gunite. Mill reports are available upon request.

SAND

Fine aggregates shall consist of washed sand and shall be hard, dense, durable, clean, sharp and graded evenly from fine to coarse in accordance with the “Standard Specifications for Concrete Aggregates,” A.S.T.M. Designation: C33-67. It shall be free from organic matter and shall not contain more than 5% by weight of deleterious substances. Sand is purchased and transported from a third-party vendor, and not produced by Texan Gunite. Sand purchased by Texan Gunite is DOT Certified Sand by the State of Texas. Mill reports are available upon request.   

WATER
Water used for hydration at the nozzle shall be at minimum fit for drinking and should meet or exceed ASTM C1602/ C1602M-06 and shall be maintained at a uniform pressure which shall be at least 110 PSI (a water booster pump will be used for this). A site with a soft water conditioner will have to find another water source as the salt water is harmful to both the concrete and the steel reinforcement. Water is supplied by the client at the site of the project whether from the house itself (city or municipality), a water well, or a water truck. Water quality is important and can affect the overall quality and strength of the gunite.