CMAX® Cement FAQ’s
Q # 1: What is CMAX® Cement?
A: CMAX Cement is a patented and proprietary formula for blended, hydraulic, ultra-high-performance cement. Its main component is a Calcium-Sulfo- Aluminate cement crystals, which are produced per CMAX ’s proprietary technology and techniques using state of the art X-ray diffraction technology.
Q # 2: Does CMAX® Cement behave similar to Portland Cement?
A: Yes, CMAX Cement has most of the Portland cement constituents with varying percentages and hydration mechanisms.
Q # 3: Does CMAX® Cement contain pozzolan?
A: No, CMAX Cement does not have addition pozzolan materials in its constituents. In general, Pozzolan addition to Portland cement improves the sulfate resistance. CMAX Cement has pozzolanic properties without any addition resulting in very high sulfate resistant. Pozzolanic raw materials may be incorporated to further enhance properties.
Q # 4: Does CMAX® Cement contain fly ash?
A: No, CMAX Cement has no fly ash in its constituents. Typically, fly ash is used to improve the sulfate resistance of concrete. This is dependent on the chemical composition of the fly ash. In some cases of low (silica/alumina +iron) percentages, fly ash does not improve sulfate resistance in CMAX Cement.
Q # 5: Is CMAX® Cement high alumina cement?
A: No, CMAX is not high alumina cement even though its chemical analysis shows higher aluminum percentages than ordinary Portland cement. CMAX Cement is not fire proof, therefore not refractory cement such as high alumina cement.
Q # 6: Is CMAX® Cement hydraulic cement?
A: Yes, CMAX Cement is hydraulic cement, as all of its hydration reactions are completed in an aqueous solution exactly as Portland cement.
Q # 7: What is the category or type of CMAX® Cement?
A: CMAX Cement could be considered as Portland cement Type I, taking into consideration the criteria for the acceptance of a higher SO3 content as per ASTM C 150. Furthermore, CMAX ® Cement is a hydraulic cement, its performance and specifications exceed the requirements of (ASTM – C 1157) and (ASTM-C 1600) in the categories of general use, early high strength and sulfate resistant cement.
Q # 8: What is the strength ranges vs. age of CMAX® Cement concrete?
A: CMAX Cement can develop strength of 5000 psi in 1 hour & 10,000 psi in 28 days as per (ASTM – C 109).
CMAX Cement concrete develops wide ranges of strengths at different ages according to the mix design in which cement content, water cement ratio and gravel qualities are specified. Strengths of 3000 psi in three hours and 8000 psi in 28 days are normal with 1.5″ max size gravel, and 0.35 water cement ratio and eight bag cement content per cubic yard.
Q # 9: What is the chemical composition of CMAX® Cement?
A: Request from technical representative.
Q # 10: Why there are some percentages higher than what is allowed in Portland cement?
A: Per (ASTM – C 150), SO3 content could be higher than the specified limits when the SO3 is not soluble and when the 14 days expansion per (ASTM C1038) does not exceed the specified limit. On the other hand, CMAX Cement is a high-performance cement categorized under (ASTM – C 1157) and (ASTM – C 1600) in which chemical analysis is flexible with no upper limits to its components or ingredients.
Q # 11: Why is the SO3 content very high compared to Portland cement?
A: In Portland cement, the only source of sulfur is the gypsum, which is used as set control. Higher percentages of gypsum affect the setting time and the soundness of the cement. In CMAX Cement the sulfur is not soluble and is part of CMAX ’s crystal matrix, which have an alternate function and behavior.
Q # 12: Is the fast setting quality a result of any chloride component in CMAX® Cement?
A: No, CMAX is non-chloride cement. Its fast setting quality is related to a different hydration mechanism.
Q # 13: What is the typical setting time for CMAX® Cement?
A: The initial setting time for CMAX Cement is 10 to 15 minutes, and the final setting time is 15 to 20 minutes. In cold weather longer working time is expected, and shorter time under hot temperature.
Q # 14: How could the working time for CMAX® Cement be extended?
A: Working in low temperatures extends the setting time. Blending with Portland cement extends the working time of CMAX mixes and using UC Delay extends the setting time up to any desirable level. The percentage of the UC Delay depends on the quality of the aggregates, so it is recommended to carry out a field test to have an idea about the actual setting time and the proper percentage of retarding agent. Note: Portland Cement will reduce strength development.
Q # 15: What is the effect of high temperatures on setting time?
A: Initial and final set times are reduced in other words the hydration reactions are enhanced and make the cement set faster.
Q # 16: Is CMAX® Cement sulfate resistance due to low C3A content?
A: CMAX ® Cement is sulfate resistant for reasons other than the low C3A content. Due to CMAX ’s unique hydration mechanism, higher C3A content could be available without any negative impact on the sulfate resistance quality.
Q # 17: What makes CMAX® Cement sulfate resistant?
A: CMAX Cement is sulfate resistant due to a completely different mechanism. Type V Portland cement is considered to be sulfate resistant due to the reduction of the destructive reactions to a minimum level characterized by 5% max C3A content. In CMAX Cement, the destructive reactions take place entirely in the plastic stage of hydration. No surplus percentage of C3A is left for later reaction.
Q # 18: Is CMAX® Cement expansive cement?
A: No, CMAX Cement is non-shrink, non-expansive and volume stable cement. However, CMAX Cement’s Type K Cement as a finished product and CMAX Type K Concentrate Additive are available and are expansive cements.
Q # 19: How is CMAX® Cement related to Type-K or shrinkage compensating cement?
A: CMAX Cement was developed through the research carried out on the expansive ettringites which are responsible for the expansive behavior of Type K cement. The proprietary formulation of ettringites in CMAX Cement are not expansive though they share the same chemical formula, Calcium Aluminum Sulfate.
Q # 20: What is the mechanism of lowering shrinkage in CMAX® Cement?
A: CMAX Cement is shrinkage reducing cement; this quality is achieved by three factors:
(1) Higher hydration water requirements, which is almost 50% higher than that of Portland cement. This means less surplus free water in an CMAX Cement matrix.
(2) Higher rate of strength gain makes the cement matrix able to overcome any tension stresses due to evaporation; actually, hair cracks are minimized and/or eliminated in an CMAX Cement matrix.
(3) Drastic reduction of micro shrinkage cracks results in CMAX concrete with low permeability and chloride.
Q # 21: What is the relation between shrinkage and water cement ratio?
A: Additional water in the cement matrix means greater chance for lost water by evaporation; however, the shrinkage percentage of CMAX Cement is at least three times less than that of the Portland cement for the same water cement ratio.
Q # 22: What gives CMAX® Cement low permeability?
A: All of the three factors contributing to CMAX Cement low shrinkage equally contribute to the low permeability; especially the micro crystals fill the voids of the concrete matrix.
Q # 23: What is the mixing procedure of CMAX® Cement?
A: CMAX Cement is not different in this regard from Portland cement. Conventional concrete mixers could be used; however, close attention should be made to the limited working time available for placement and finishing. By using the appropriate dose of retarder UC Delay, the working time could be extended to 90 minutes or more.
Q # 24: What is the color of CMAX® Cement?
A: Natural gray, which is similar to Portland cement type III.
Q # 25: Where has CMAX® Cement been used?
A: CMAX Cement is currently being used in highway & runway panel repair, pre-casting, bagging and custom blended commercial products. CMAX Cement is utilized for any application that requires high early strength and fast setting. Practical examples are Airport Authority jobs at LAX, Sacramento, San Diego and JFK repair work. California department of transportation and dozens of DOT’s nationwide have and are utilizing CMAX Cement. Examples of jobs completed are U.S. Interstates 5 and 60 in California, Interstate 10 in Arizona and multitude others projects worldwide.
Q # 26: How is the cost of CMAX® Cement compared to other products in its category?
A: CMAX Cement is marketed at about 4 times more than ordinary Portland cement. This price differential is feasible for applications that would have higher economic impact if carried out with ordinary Portland cement.
Q # 27: What is the curing procedure for CMAX® Cement?
A: In normal weather conditions, CMAX Cement does not need curing and protection procedures. However, in extreme weather conditions some precautions should be made and or per job specifications. In hot or windy weather, excessive evaporation should be carefully prevented. In cold weather, freezing protection arrangements could be removed 30 minutes after final set, which is usually achieved in less than two hours. In any condition a curing compound sprayed will achieve optimal results.
Q # 28: Can CMAX® Cement be used as an additive to Portland cement?
A: Yes, mixing CMAX Cement with Portland cement produces a wide range of advantages which makes CMAX Cement very flexible to fit any required quality or performance. Along the full spectrum of CMAX Cement qualities, engineers can get any desired setting time from ten minutes to six hours. At the same time engineers can achieve any desired degree of CMAX qualities; strength, shrinkage eliminating, minimal permeability and sulfate resistance.
Q # 29: What is the effect of CMAX® Cement on the reinforcement or embedded steel?
A: CMAX ’s unique formula provides excellent protection for embedded and reinforcing steel. The mechanism through which CMAX attains this protection is as follows:
(1) CMAX Cement has very low permeability; this characteristic provides good protection against chemical attacks.
(2) CMAX Cement has very low chloride content seven times less than the maximum allowable. Chloride ions are the principal reason for steel corrosion in concrete masses.
(3) CMAX Cement crystals have the ability to react with the thin layer of iron dioxide rust, to form a protective layer of ettringites, which in turn, increases the passivity of the steel, and consequently eliminates corrosion.
Q # 30: Can CMAX® Cement be mixed with seawater?
A: Yes, mixing CMAX Cement with seawater is safe and does not affect the qualities of the produced concrete. Seawater meets the criteria for questionable water resources as specified in (ASTM – C 94). The setting time and the seven-day strength are within the acceptable range. In fact, mixing with seawater improves the long-term strength of the concrete when with UC Delay.
Q # 31: Does CMAX® Cement contribute to LEED and have Green properties?
A: Yes, CMAX Cement may get up to 5 LEED points. The manufacturing of CMAX Cement with lowers emissions in the following categories.
(1) 62% less CO2
(2) 80% NOx
(3) 98% SOx
Q # 32: How is CMAX® Cement sold and where is it available?
A: CMAX Cement is sold in bulk pneumatic railcars, trucks and packaged for distribution. Railcars are 100 tons, trucks are 25 tons and packaged material is in bulk bags at 2000 lbs. or small bags 88 lbs. per bag with 40 bags per pallet. Bulk Terminal locations as of 2014: Pryor, OK; Colton, CA; College Park, GA; New Orleans, LA; Dallas, TX; Stockertown, PA; Indianapolis, IN. Packaging Terminal locations as of 2014: Bayville NJ; Archie MO; Colton, CA. For further information call 714-523-2006 or e- mail at sales@CMAX cement.com for distributors and availability in your area.
Additional technical support may be provided via email inquiry for specific applications and mixing procedures if required by customer.
CC Products, a subsidiary of DBC Corporation
2400 Katella Ave, Suite 800, Anaheim California 92801
(714) 523-2006 • Fax (714) 523-2037
Email to: Info@cmaxcement.com
www.cmaxcement.com