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REPORT
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Publication Number: FHWA-HRT-05-038
Date: August 2006

 

Guide for Curing Portland Cement Concrete Pavements, II

508 CAPTIONS

Figure 1. Canopy used to protect fresh concrete. Photo. This figure shows a long strip of freshly laid concrete covered by a canopy, in a tent-like fashion, arching in the middle and traversing downward to the edges of the sides of the laid concrete.

Figure 2. General layout of the draft guide. This figure shows the layout of the draft guide, broken down into four columns of boxes, colored in a pale blue with each column connected by a vertical line. The first box sits atop the rest and represents the starting point for the rest of the layout. This first box is labeled Select Method see figure three. A small line extends downward vertically from this box to another line, which runs horizontally along the top of the four columns.

At the left-hand side of the layout, the first column begins, the horizontal line connecting to the box, bending downward vertically. This vertical line runs through the entire column of boxes. The first box is labeled Curing-Compound Methods see figure four. The second box in the column reads Choosing Curing Compounds. The third box reads Application Rate. The fourth reads Time of Application. The fifth reads Inspection. The sixth and final box in this column reads Verification of Curing.

The second column, joined to the horizontal line by a vertical line, begins with the first box that reads Water-Added Methods see figure five. The second box reads Limits on Water. The third reads Time of Application. The fourth and final box in this column reads Inspection.

The third column, joined to the horizontal line by a vertical line, begins with the first box that reads Water Retention Methods (Other than Curing Compound) see figure six. The second box reads Material. The third reads Inspection. The fourth and final line reads Verification.

Finally, the fourth column, joined to the horizontal line by a vertical line at the far right hand side of the layout, begins with the first and only box in this column, which reads Temperature Management see figures eight and nine.

At the very end of the layout is one final box, which the three lines running through the first three columns connect to. This box reads Duration of Curing see figure seven.

Figure 3. Selection among moist-curing methods. This figure shows a small layout of several columns of boxes. The first box, colored a pale blue, which starts the layout at the very top, reads Select Method. A vertical line extends from this box down to a horizontal line, which leads to the individual three columns.

At the far left-hand side of the layout is the first column, which begins with a pale blue colored box and reads Curing-Compound Methods see figure four. From this box, a vertical line extends downward, the end of the line completed with an arrowhead pointing to the final box in this column, which is colored white. This box contains three lines of information. The first line reads Large areas of concrete. The second line reads Curing Compound only practical option. The third and final line reads Water or other curing materials unavailable.

The second column, located directly under the starting box, and connected to the horizontal line by a vertical line extending downward, is colored a pale blue and reads Water-Added Methods see figure five. From this box a vertical line extends downward. This line is bisected with a small line of information highlighted with bold lettering, which reads Decision Criteria. The line continues through this, the end of the line completed with an arrowhead pointing to the final box in this column, which is colored white. This box contains two lines of information. The first line reads Water-cement ratio is less than 0.4. The second line reads Use of expansive cement.

At the far right hand side of the layout is the third column, which begins with a pale blue colored box and reads Water-Retention Methods (other than curing compounds) see figure six. From this box, a vertical line extends downward, the end of the line completed with an arrowhead pointing to the final box in this column, which is colored white. This box contains three lines of information. The first line reads Water-cement ratio is less than 0.4. The second line reads Curing Compounds not suitable, cost, availability, and bonding problems. The third and final line reads Non-windy conditions.

Figure 4. Decision criteria for curing-compound methods. This figure shows a layout of one column of boxes, colored a pale blue to the left-hand side of the page, and another column of information to the right hand side of the page, containing details pertaining to the individual boxes on the left. The top of the layout begins with one box, colored pale blue, that reads Curing Compound Methods. The column of boxes extends downward from this box.

The first box in the column reads Choosing Curing Compound. A horizontal line extends from this box and branches out to three lines of details. The first line reads Pigmented versus non-pigmented. The second line reads Organic solvent versus low VOC. The third line reads Specification. This third line of information branches out into three more lines of detail. The first line reads ASTM C 309. The second line reads ASTM C 1315. The third and final line reads other.

The second box in the column reads Application Rate. A horizontal line extends from this box and branches out to three lines of details. The first line reads Manufacturer's guidance. The second line reads Standard guidance. This second line of information branches out into three more lines of detail. The first line reads ACI 301. The second line reads AASHTO G.S. The third line reads other. The third and final line of the original branch reads Custom.

The third box in the column reads Time of Application. A horizontal line extends from this box and branches out to two lines of details. The first line reads Non-bleeding and branches out into two lines of details. The first line reads Evap rate less than 1.0 kilograms per cubic meter per hour-after finishing. The second line reads Evap rate greater than 1.0 kilograms per cubic meter per hour-retard evap, apply after finishing. The second line of the original branch reads Bleeding and branches out into two more lines of detail. The first line reads Evap greater than bleed-retard evap, apply after finishing. The second line reads Evap less than bleed-after surface sheen disappears.

The fourth box in the column reads Inspection. A horizontal line extends from this box and branches out to two lines of details. The first line reads Prescriptive-equipment, application rate. The second line reads Performance-verify after application.

The five box in the column reads Verifying Curing. A horizontal line extends from this box and branches out to two lines of details. The first line reads Prescriptive. The second line reads Performance-in place measures.

The sixth and final box in the column reads Duration of Curing. A horizontal line extends from this box to one line of detail that reads See figure seven.

Figure 5. Decision criteria for water-added methods. This figure shows a layout of one column of boxes, colored a pale blue to the left-hand side of the page, and another column of information to the right hand side of the page, containing details pertaining to the individual boxes on the left. The top of the layout begins with one box, colored pale blue, that reads Water-Added Methods. The column of boxes extends downward from this box.

The first box in the column reads Material requirements. A horizontal line extends from this box and branches out into three lines of details. The first line reads Temperature of curing water. The second line reads Dissolved materials. The third line reads Absorbent materials.

The second box in the column reads Time of Application. A horizontal line extends from this box and branches out into two lines of details. The first line reads If evap rate is greater than or equal to 1.0 kilograms per meters squared per hour, then fog, apply is greater than finishing. The second line reads If evap rate is less than 1.0 kilograms per meters squared per hour, then apply is greater than finishing.

The third box in the column reads Inspection. A horizontal line extends from this box to one line of detail, which reads Visual.

The fourth and final box in the column reads Duration of Curing. A horizontal line extends from this box to one line of detail, which reads See figure seven.

Figure 6. Decision criteria for water-retentive methods other than those using curing compounds. This figure shows a layout of one column of boxes, colored a pale blue to the left-hand side of the page, and another column of information to the right hand side of the page, containing details pertaining to the individual boxes on the left. The top of the layout begins with one box, colored pale blue, that reads Water-Retention Methods (other than curing compound). The column of boxes extends downward from this box.

The first box in the column reads Materials. A horizontal line extends from this box to one line of details. This line reads Sheet material. The sub-details of this line read Temp is less than 15 degrees Celsius, reflecting, and Temp is greater than 15 degrees Celsius, non-reflecting.

The second box in the column reads Time of Application. A horizontal line extends from this box and branches out into two lines of details. The first line reads If evap rate is greater than or equal to 0.2, fog, apply is greater than TOS. The second line reads If evap rate is less than 0.2, apply is greater than TOS.

The third box in the column reads Inspection. A horizontal line extends from this box to one line of detail, which reads Visual.

The fourth box in the column reads Verification. A horizontal line extends from this box and branches out into two lines of details. The first line reads Prescriptive. The second line reads Performance.

The fifth and final box in the column reads Duration of Curing. A horizontal line extends from this box to one line of detail, which reads See figure seven.

Figure 7. Decision criteria for duration of curing. This figure shows a layout of various information. The layout begins to the far left-hand side of the page with a pale-colored blue box that reads Duration of Curing. A horizontal line extends from the right-hand side of this box and branches out into two separate lines of detail.

The first line of detail reads Prescription. This line of detail then branches out into two more separate lines of information. The first line of information reads Temperature is less than 10 degrees Celsius, and contains two sub-details; the first line of sub-detail reads AASHTO-3 days, pavement, 7 days, structures, 10 days, greater than 10 percent pozz. The second line of sub-detail reads ACI 7 days, Type 1 cement. The second line of information reads temperature is less than 10 degrees Celsius-Table 6.8, ACI 306R.

The second line of detail in the original branch reads Performance. This line of detail then branches out into four more separate lines of information. The first line of information reads ACI 301 percent f-prime c, or 100 percent f-prime c, NDT methods. The second line of information reads ACI 308.1 70 percent f-prime c, or if durability achieved. The third line of information reads AASHTO 70 percent f-prime c. The fourth and final line reads Caution about cold temperature effects on the NSZ.

Figure 8. Decision criteria for temperature management in hot weather. This figure shows a layout of one column of boxes, colored a pale blue to the left-hand side of the page, and another column of information to the right-hand side of the page, containing details pertaining to the individual boxes on the left. The top of the layout begins with one box, colored pale blue that reads Temperature Management Hot Weather. The column of boxes extends downward from this box.

The first box in the column reads Expected d T. A horizontal line extends from this box and branches out into two lines of details. The first line reads From heat of hydration. The second line reads From environmental effects.

The second box in the column reads Limits. A horizontal line extends from this box and branches out into two lines of details. The first line reads Thermal Stress. The second line reads Strength reductions.

The third box in the column reads Adjustments to Curing Methods. A horizontal line extends from this box to five lines of detail. The first line reads Precool materials. The second line reads Cure with added water. The third line reads Use white-pigmented sheets. The fourth reads Use white-pigmented curing compound (adjust application rate). And the fifth and final line reads time-of-day considerations.

The fourth and final box in the column reads Curing Time. A horizontal line extends from this box to one line of detail, which reads See figure seven.

Figure 9. Decision criteria for temperature management in cold weather. This figure shows a layout of one column of boxes, colored a pale blue to the left-hand side of the page, and another column of information to the right-hand side of the page, containing details pertaining to the individual boxes on the left. The top of the layout begins with one box, colored pale blue, that reads Temperature Management Cold Weather. The column of boxes extends downward from this box.

The first box in the column reads Limits. A horizontal line extends from this box and branches out into three lines of details. The first line reads Minimum strength, one freezing event. The second line reads Minimum strength, F slash T cycling. The third line reads Critical Environmental Temperatures.

The second box in the column reads Protection. A horizontal line extends from this box and branches out into two lines of details. The first line reads Insulation, and has a sub-detail line, which reads To maintain 10 degrees Celsius custom temperature. The second line reads Heated enclosures.

The third box in the column reads Moisture Retention. A horizontal line extends from this box to two lines of detail. The first line reads Air temperature is greater than 10 degrees Celsius. The second line reads Air temperature is less than or equal to 10 degrees Celsius.

The fourth and final box in the column reads Curing Time. A horizontal line extends from this box to one line of detail, which reads See figure seven.

Figure 10. Calculated versus measured evaporation rates. Wind directly on the free-water surface. Graph.

This figure is a graph that shows two distinct lines rising, one shallow, one steeply, across the length of a graph. There appear a number of blue diamonds placed about the surface of this graph. The vertical axis of this graph ranges from 0.00 to 1.60 and represents Measured, kilograms per meters squared per hour. The horizontal axis of this graph ranges from 0.00 to 0.60 and represents Calculated from nomograph, kilograms per meters squared per hour. The top left-hand corner of this graph hosts two lines of information. The first line reads Y equals 2.332X plus 0.1584. The second line reads R squared equals 0.748.

The upper line on the graph is solid black and begins at the points of 0.30 on the vertical axis and 0.06 on the horizontal axis. The line rises steeply across the graph to the points of 1.40 on the vertical axis and 0.55 on the horizontal axis. This line is marked as "observed."

The lower line on the graph is black dotted and begins at the points of 0.05 on the vertical axis and 0.10 on the horizontal axis. The line rises at a shallow angle to the points of 0.40 on the vertical axis and 0.50 on the horizontal axis. This line is marked as "line of equivalency."

Figure 11. Comparison of total water lost, expected from the ACI 308 nomograph, and bleed rate of a 0.45 water-cement concrete. Graph.

This figure is a graph that shows three distinct lines rising in individual slopes across the length of the graph. The upper line is solid green and is labeled Total measured mass loss. The middle line is solid black and is labeled Total measured bleeding. The lower line is solid red and is labeled Total calculated evaporation. The vertical axis of this graph ranges from 0 to 16 and represents Mass Loss, kilograms per meters squared, while the horizontal axis ranges from 0 to 5 and represents Time, hours. All three lines begin at the points of zero on both the vertical and horizontal axes. The green line slopes upward from zero steeply and comes to an end at the points of 15 on the vertical axis and 4 on the horizontal axis. The black line slopes up gradually from the points of zero to the points of 2.3 on the vertical axis and 3.8 on the horizontal axis. Finally, the red line slopes up gradually from the points of zero to the points of 2 on the vertical axis and 4 on the horizontal axis.

Figure 12. Evaporation of water from a 0.37 water-cement specimen compared with the rate expected from the ACI 308 nomograph. Surface temperature changes approximately track evaporation rates. Graph.

This figure is a graph that shows three distinct lines running in a gradual incline across a graph. The upper line is solid green. The middle line is solid black, and the lower line is solid red. The left-hand vertical axis of this graph ranges from 0 to 10 and represents Mass loss, kilograms per meters squared, while the horizontal axis of this graph ranges from 0 to 6 and represents Time in hours. The right-hand vertical axis ranges from 10 to 40 and represents Temperature in degrees Celsius.

The green line begins at the points of 4.4 on the left-hand vertical axis and zero on the horizontal axis. From there, it slopes up gradually to the points of 6 on the left-hand vertical axis and 3.3 on the horizontal axis. At this point, the line continues upward in a steeper fashion, until it leaves the graph at the points of 8.5 on the left-hand vertical axis, 6 on the horizontal axis, and 36 on the right-hand vertical axis.

The black line begins at the points of zero on the left-hand vertical axis, 10 on the right-hand vertical axis, and zero on the horizontal axis. From there it continues across the graph in a gradual upward slope until it leaves the graph at he points of 3.5 on the left-hand vertical axis, 6 on the horizontal axis and 22 on the right-hand vertical axis.

The red line begins at the points of zero on the left-hand vertical axis, 10 on the right-hand vertical axis, and zero on the horizontal axis. From there it continues across the graph in a gradual upward slope until it comes to a stop at the points of 2.5 on the left-hand vertical axis, 5.9 on the horizontal axis, and 20 on the right-hand vertical axis.

Figure 13. Bleeding pattern of a 0.45 water-cement concrete. Graph.

This figure is a graph that shows one distinct blue line, making its way across a graph jaggedly, stopping at variable points along its path. The vertical axis of this graph ranges from 0.00 to 0.35 and represents Bleed Rate in kilograms per meters squared per hour, while the horizontal axis of this graph ranges from 0 to 6 and represents Time in hours.

The blue line begins at the points of 0.025 on the vertical axis and 1 on the horizontal axis. From there it spikes upwards to the points of 0.24 on the vertical axis and 1.6 on the horizontal axis, where it then descends steeply to the points of 0.14 on the vertical axis and 2 on the horizontal axis. From there, the line spikes up one last time to the points of 0.33 on the vertical axis and 2.5 on the horizontal axis where it then descends to the points of 0.15 on the vertical axis and 4 on the horizontal axis. The blue lines plateaus at this points for a brief time before it descends from the points of 0.15 on the vertical axis and 4.5 on the horizontal axis to the points of zero on the vertical axis and 5 on the horizontal axis.

Figure 14. Bleeding rate per unit thickness of concrete (centimeters) versus water-cement ratio. Graph.

This figure is a graph that shows one solid black line rising across the graph. There appear a number of blue diamonds placed about the surface of this graph. The lower right-hand side of the graph hosts two lines of information. The first line reads Y equals 0.0514X minus 0.0151. The second line reads R squared equals 0.633. The vertical axis of this graph ranges from 0 to 0.012 and represents Bleed Rate in kilograms per meters squared per hours per centimeter, while the horizontal axis of this graph ranges from 0.3 to 0.55 and represents water-cement ratio.

The solid black line begins at the points of 0.003 on the vertical axis and 0.35 on the horizontal axis. From there it runs across the graph in a straight incline until it ends at the points of 0.02 on the vertical axis and 0.5 on the horizontal axis.

Figure 15. Development of spall as a result of early application of curing compound. Photo.

This photo shows a section of concrete that fills almost the entire width of the frame, leveled off at the top in a straight plane. The front of the concrete is a grayish-blue, and appears to contain medium-sized stone, which are flattened along with the section's front surface. The top of the concrete section is a dark gray, with lines running in unison diagonally across the flat surface. There are two lines of text printed on the front of the concrete section. The first line reads sub-surface crack, and points (with red arrows) to three areas of the concrete near the top surface on the left-hand corner of the section, the center of the section, and between these two areas. The second line reads spall and points (with a red arrow) to one part of the concrete section nearly dead center, along the front edge of the concrete section. A small triangular sliver of concrete appears to be missing from the top surface.

Figure 16. Cracked curing membrane resulting from application before cessation of bleeding. Photo.

This photo shows a section of concrete that occupies the entire frame. The surface of the concrete appears smooth and has a green-marbleized appearance to it. Along the top of the photo, appears a crack that runs the length of the top of the concrete section. A small white piece of paper is taped to the concrete section that reads 10.11.01, FHWA, 13-3.

Figure 17. Rebound number of concrete surface versus water loss in final curing period (7 days). Graph.

This figure is a graph that shows black dots placed variably throughout the graph, with a dotted black line bisecting the graph diagonally. The upper portion of this graph hosts two lines of information. The first line reads Rebound number equals 25 minus 4.8 parenthesis water loss in final curing period end parenthesis. The second line reads R squared equals 70 percent. The vertical axis of this graph ranges from 5 to 35 and represents Rebound Number. The horizontal axis of this graph ranges from 0 to 4 and represents Water loss minus final curing period in kilograms per meter squared.

Figure 18. Surface water absorption versus water loss during the final curing period (7 days). Graph.

This figure is a graph that shows black dots placed variably throughout the graph, with a dotted black line bisecting the graph diagonally. The upper portion of this graph hosts two lines of information. The first line reads Water abs equals 0.17 plus 0.11 (mass loss final curing period). The second line reads R squared equals 61 percent. The vertical axis of this graph ranges from 0.1 to 0.9 and represents Water absorption in kilograms per meter squared. The horizontal axis of this graph ranges from 0 to 4 and represents Water loss minus final curing period in kilograms per meter squared.

Figure 19. Water loss at 72 hours versus application rate of curing compound. The more conventional representation of application rate (meters squared per liter) is annotated by each point. Graph.

This figure is a graph that shows one distinct line moving across a graph, beginning near the upper left- hand corner of the graph and ending near the lower right-hand side of the graph. The vertical axis of this graph ranges from zero to 4 and represents Water loss in kilograms per meters squared, while the horizontal axis of this graph ranges from 0.0 to 0.4 and represents Application Rate in kilograms per meters squared. The beginning point of the line is labeled as No Curing Compound. The line itself begins at the points of 3.5 on the vertical axis and 0.0 on the horizontal axis. The line descends in one continuous slope from this point and hosts several distinct points of interest along its path across the graph. The first point is found at 1 on the vertical axis and 0.1 on the horizontal axis and is labeled 9.7 meters squared per liter. The second point of interest is found at 0.75 on the vertical axis and 0.199 on the horizontal axis and is labeled 5.4 meters squared per liter. The final points of interest also marks the end of the descending line at the points of 0.35 on the vertical axis and 0.375 on the horizontal axis. This point of interest is labeled 2.6 meters squared per liter.

Figure 20. Surface water absorption versus application rate of curing compound. Graph.

This figure shows one distinct line labeled "no curing compound" moving across a graph, beginning near the upper left hand corner of the graph and ending near the lower right-hand side of the graph. The vertical axis of this graph ranges from 0.0 to 0.9 and represents Water Absorption in kilograms per meters squared while the horizontal axis of this graph ranges from 0.0 to 0.4 and represents Application Rate in kilograms per meters squared. The distinct line is above a horizontal line representing a water absorption of about 0.22 kilograms per meters squared. Points shown on the distinct line are (0, 0.8) for no curing compound, (0.1, 0.4) for 9.7 meters squared per liter application rate, (0.2, 0.35) for 5.4 meters squared per liter application rate, and ((0.38, 0.23) f0r 2.6 meters squared per liter application rate.

Figure 21. Rebound number versus application rate of curing compound. Graph.

This graph shows one distinct line moving across a graph, with four points of interest specifically marked along its path. The vertical axis of this graph ranges from 0 to 25 and represents Rebound number, while the horizontal axis of this graph ranges from 0.0 to 0.4 and represents Application Rate in kilograms per meters squared. There are two lines that bisect the graph. Both begin at the left side and cut across the face of the graph and extend to its far side. The upper line is a dotted line that bisects the graph at the points of about 22 on the vertical axis and 0.0 on the horizontal axis and runs across the graph in one straight line to the far end. This line is labeled Control - No Water Lost. The lower line is a solid line that bisects the graph in a diagonal fashion, at the points of 8 on the vertical axis and 0.0 on the horizontal axis. This line runs across the graph and ends in the graph's far right-hand upper corner. This beginning point (first point of interest) of the line on the graph is labeled as No Curing Compound. The second point of interest is marked at 20 on the vertical axis and 0.1 on the horizontal axis and is labeled 9.7 meters squared per liter. The third point of interest is marked at 20 on the vertical axis and 0.2 on the horizontal axis and is labeled 5.4 meters squared per liter. The fourth and final point of interest is marked at 23 on the vertical axis and 0.375 on the horizontal axis, which also marks the end of the line.

Figure 22. Comparison of calculated versus measured drying tomes for six curing compounds with observed drying times under a range of drying conditions. Graph.

This figure is a graph that shows a straight line running diagonally across a graph. There appear a number of blue diamonds placed about this graph. The vertical axis of this graph ranges from 0.0 to 20 in increments of two and represents Predicted, in hours, while the horizontal axis of this graph ranges from 0 to 20 and represents Observed, in hours. At each increment of two, a straight line is extended across the face of the graph, lining its surface. The line running diagonally across the graph begins at the points of zero on both the vertical and horizontal axes and runs off the graph at the points of 20.0 and the vertical axis and 20 on the horizontal axis, cutting the graph in two equal triangular halves. A cluster of four diamonds can be found at midpoint between 0.0 and 2.0 on the vertical axis near 1 and 2 on the horizontal axis. Three more diamonds are placed along the line that extends from the point of 2.0 on the vertical axis. These diamonds are placed near the diagonal line. Another cluster of diamonds is spread out in a line between the points of 2.0 and 4.0 on the vertical axis near the points of 3, 4, and 5 on the horizontal axis. Four more diamonds are set in a row along the line that extends from the point of 4.0 on the vertical axis. These diamonds spread from the points of 2 to 6 on the horizontal axis. Finally, two more diamonds are placed along the line that extends from the point of 16.0 on the vertical axis. The first is placed near the point of 10 on the horizontal axis while the second is placed near the point of 18 on the horizontal axis.

Figure 23. Effect of curing compound application on concrete surface. Graph.

This figure shows three distinct lines moving across a graph. The first line is solid blue with blue squares and represents "With curing compound." The second line is solid red with red triangle and represents "No curing compound." The third and final line is green dotted and represents "room temperature." The top of this graph is headed with the title ASTM C 156 Mortar, in bold lettering. The vertical axis of this graph ranges from 20 to 45 and represents Temperature in degrees Celsius, while the horizontal axis of this graph ranges from 0 to 25 and represents Time in hours. The blue and red lines begin at the points of 22.5 on the vertical axis and zero on the horizontal axis. Both make an upward arch, the blue line to the points of 41 on the vertical axis and 4 on the horizontal axis, the red to the points of 38 on the vertical axis and 6 on the horizontal axis. From these points, both lines begin their descent in a straight line, converging at the very end at the points of 36 on the vertical axis and 24 on the horizontal axis. The green line begins at the points of 36 on the vertical axis and 0 on the horizontal axis. From there it wavers a little bit across the graph before it straightens out and converges with the first two lines coming to an end at the points of 36 on the vertical axis and 24 on the horizontal axis.

Figure 24. Fresh mortar specimens with variable applications of white pigmented curing compound. The top four specimens contained 15.2, 7.9, 5.4, and 3.2 meters squared per liter (left to right). The bottom three specimens were treated as unknowns (see table 12.) Photo.

This figure is a photo that shows seven circular cutouts or discs of concrete, arranged in two different rows, placed atop a white cloth. The top row contains four specimens. The first of the four discs is a dark grayish color. The second in the row appears a lighter shade of gray. The third in the row look to be closer to an ivory color, while the fourth in the row is nearly white. Of the second row, the three discs pictured get progressively light across the row, the first a medium to light gray in color, the second an ivory color and the third nearly white.

Figure 25. Black construction-paper specimens with variable applications of white-pigmented curing compound. The top four specimens contained 10.1, 7.5, 5.9, and 4.5 meters squared per liter (left to right). The bottom three specimens were treated as unknowns (see table 13). Photo.

This figure is a photo that shows seven square cutouts, arranged in two different rows, placed atop a white cloth. The top row contains four specimens. The first square is a dark grayish color. The second in the row appears a lighter shade of gray. The third in the row looks to be only slightly lighter in color than the latter, while the fourth in the row is nearly light gray. Of the second row, the first in the row appears a medium shade of gray, the second only slightly lighter than the latter, and the third nearly a light gray in color.

Figure 26. Reflectance versus application rate for white-pigmented curing compound applied to fresh mortar at different rates. Data points represented by open symbols were treated as unknowns. Graph.

This figure is a graph that shows one distinct line descending in a reverse arch across the length of a graph, with various points on the graph marked with solid black diamonds and squares. The diamonds represent Standards, while the squares represent Unknowns. The lower left-hand side of the graph hosts a few lines of information. The first line reads Y equals 122.09X superscript minus 0.3749. The second line of information reads R squared equals 0.9666. The vertical axis of this graph ranges from 20 to 90 and represents Reflectance in percentage, while the horizontal axis of this graph ranges from zero to 20 and represents Application Rate in meters squared per liter. The line begins at the points of 80 on the vertical axis and 3.5 on the horizontal axis where it slopes downward and comes to an end at the points of 45 on the vertical axis and 15 on the horizontal axis. There are a total of three squares marked on the graph. The first is located at the points of 80 on the vertical axis and 4 on the horizontal axis. The second is at the points 68 on the vertical axis and 6 on the horizontal axis. Finally, the third is located at the points of 50 on the vertical axis and 13 on the horizontal axis. There also appear a total of three diamonds on this graph, the first located at the points of 76 on the vertical axis and 3.5 on the horizontal axis. The second is located at the points of 70 on the vertical axis and 5 on the horizontal axis. The final diamond is located at the points of 45 on the vertical axis and 15 on the horizontal axis.

Figure 27. Reflectance versus application rate for white pigmented curing compound applied to black-paper specimens at different rates. Data points represented by open symbols were treated as unknowns. Graph.

This figure is a graph that shows one distinct line on a graph, dotted with black diamonds and black squares at specific points along its path. To the right of the graph appears a legend. Within the legend are specific items. The first item is a solid black diamond labeled Standards. The second item in the legend is a black square labeled Unknown. The lower portion of this graph hosts a couple lines of information. The first line reads Y equals 95.209X superscript minus 0.2922. The second line reads R squared equals 0.9377. The vertical axis of this graph ranges from 20 to 90 and represents reflectance in percentage. The horizontal axis of this graph ranges from zero to 12 and represents Application rate in meters squared per liter. The line begins at the points of 60 on the vertical axis and 4 on the horizontal axis where it slopes down very gradually and comes to an end at the points of 50 on the vertical axis and 10 on the horizontal axis. Four diamonds are placed along the exact path of the line, one at the beginning, one at its end and the other two one the line at the points between 60 and 50 on the vertical axis and directly above 6 on the horizontal axis. Three squares are also placed along the line's path. The first at the line's beginning. The second is located at the points of 7 on the vertical axis and 6 on the horizontal axis. The third and final square is located at the points of 55 on the vertical axis and 9 on the horizontal axis.

Figure 28. Effect of curing quality on development of rebound number at early ages. Specimens cured at 38 degrees Celsius. Graph.

This figure is a graph that shows three distinct lines running in straight lines across the length of a graph. The vertical axis of this graph ranges from zero to 30 and represents Rebound Number, while the horizontal axis of this graph ranges from zero to 12 and represents time in days. The first line begins at the points of 20 on the vertical axis and 1 on the horizontal axis where it cuts across the graph in a straight diagonal line and ends at the points of 23 on the vertical axis and 10 on the horizontal axis. Several solid blue diamonds are placed along the line's direct path. The line itself is labeled Bottom of Specimen, Well Cured. The second line begins at the points of 10 on the vertical axis and 1 on the horizontal axis where it cuts across the graph in a straight diagonal line and ends at the points of 13 on the vertical axis and 10 on the horizontal axis. Several black squares are placed along the line's direct path. The line itself is labeled Top Surface-Weak Curing, Curing Compound-10 meters squared per liter. The third and final line begins at the points of 7 on the vertical axis and 1 on the horizontal axis where it cuts across the graph in a straight diagonal line and ends at the points of 9 on the vertical axis and 10 on the horizontal axis. Several black triangles are placed along the line's path. The line itself is labeled Top Surface, No curing.

Figure 29. Effect of curing condition on rebound number of top surface of specimens at 7 days. Graph.

This figure shows a graph containing four columns, each with their respective labels and rising to a certain point on the vertical axis. The vertical axis of this graph ranges from zero to 25 and represents Rebound Number. The horizontal axis of this graph represents Curing Treatment. The first column on this graph is labeled No Curing and rises to the point of eight on the vertical axis. The second column of this graph is labeled Light Curing Compound and rises to the point of twenty on the vertical axis. The third column of this graph is labeled Heavy Curing Compound and rises to the point of 23 on the vertical axis. Finally, the remaining column of this graph is labeled Plastic Sheet and rises to the point of 24 on the vertical axis.

Figure 30. Correlation between rebound number and surface water absorption. Graph.

This figure is a graph that shows one distinct straight line descending across the length of a graph diagonally. Several clusters of small black circles inhabit the areas around the length of the line, from top to bottom. The bottom left-hand corner of this graph hosts two lines of information. The first line reads Y equals minus 0.0211X plus 0.717, and the second line reads R equals 0.7848. The vertical axis of this graph ranges from 0.0 to 0.7 and represents Water Absorption in kilograms per meters squared. The horizontal axis of this graph ranges from 5 to 30 and represents rebound number. The line begins at the points of 0.5 on the vertical axis and 9 on the horizontal axis where it descends in a straight line to the points of 0.1 on the vertical axis and 28 on the horizontal axis and comes to an end.

Figure 31. Surface water absorption versus depth for concrete cured with different methods. Graph and legend.

This figure is a graph that shows several distinct lines working their way across a graph and several distinct shapes marking specific points on the graph. To the right of the graph appears a legend. Within the legend are the following specific items. The first item in the legend is a solid black diamond labeled Plastic. The second item is a black square labeled Light CC. The third item is a black triangle labeled Heavy CC. The fourth item is a black X labeled No CC. The fifth item in the legend is a thick, solid black line labeled Log parenthesis no CC end parenthesis. The sixth item is a black dotted line labeled Log (light CC). The seventh item in the legend is a thin, solid black line labeled Linear parenthesis heavy CC end parenthesis. Finally, the eight and final item in the legend is a black dotted and dashed black line labeled Linear parenthesis plastic end parenthesis. The vertical axis of this graph ranges from 0.000 to 0.700 and represents Absorption in kilograms per meters squared. The horizontal axis of this graph ranges from zero to 200 and represents Depth in millimeters. The first line, the thick, solid black line, begins at the points of 0.600 on the vertical axis and 10 on the horizontal axis where it curves downward and comes to an end at the points of 0.300 on the vertical axis and 60 on the horizontal axis. Four black X symbols are placed along the path of this line, one at the beginning, one at the end, and two in the middle near the 0.400 mark on the vertical axis. The next line, the black dotted line, begins at the points of 0.300 on the vertical axis and zero on the horizontal axis were it curves gradually in a downward slope and comes to an end at the points of 0.200 on the vertical axis and 70 on the horizontal axis. Five black squares are placed along the path of this line, two near the beginning, one at the line's end and two others just above the 0.200 mark on the vertical axis and the 40 mark on the horizontal axis. The next line, the thin, solid black line begins at the points of 0.200 on the vertical axis and zero on the horizontal axis and descends in a short straight line, coming to an end at the points of 0.150 on the vertical axis and 40 on the horizontal axis. Four black triangles are placed along the path of this line, two at its beginning and two at its end. The final line, the black dotted and dashed line begins at the points of 0.150 on the vertical axis and 20 on the horizontal axis where it runs across the graph in a straight line and comes to an end at the points of 0.200 on the vertical axis and 150 on the horizontal axis. An array of solid black diamonds is placed along this line's path, two at its beginning, two at its end, and a small cluster at the points of 0.150 on the vertical axis and 40 on the horizontal axis.

Figure 32. Relationship between shrinkage of near-surface zone of concrete and water absorption after 11 days of exposure to drying conditions. Graph.

This figure is a graph that shows one distinct line descending across a graph in a diagonally straight line. There appear several black diamonds placed along the path of the line at specific points on the graph. The vertical axis of this graph ranges from negative 0.6 to zero and represents Length Change in percentage, while the horizontal axis parenthesis located at the top of this graph end parenthesis ranges from zero to 0.7 and represents Water Absorption in kilograms per meters squared. The line begins at the points of negative 0.15 on the vertical axis and 0.1 on the horizontal axis and descends in a straight diagonal line from there and ends at the points of negative 0.525 on the vertical axis and 0.6 on the horizontal axis. The first diamond is placed near the top of the line at the points of negative 0.1 on the vertical axis and 0.175 on the horizontal axis. The second diamond is located at the points of negative 0.25 on the vertical axis and 0.2 on the horizontal axis. The third diamond is placed at the points of negative 0.3 on the vertical axis and 0.25 on the horizontal axis. Finally, the fourth diamond is placed at the points of negative 0.5 on the vertical axis and 0.6 on the horizontal axis.

Figure 33. Relationship between maximum temperature gradient between concrete surface and 50-millimeter depth versus initial evaporation rate calculated from the ACI nomograph. Graph.

This figure is a graph that shows one distinct line rising in an arch across a graph. The vertical axis of this graph ranges from zero to 25 and represents Temperature difference in degrees Celsius, while the horizontal axis of this graph ranges from zero to 3.5 and represents initial evaporation rate in kilograms per meters squared per hour. The line begins at the points of 7 on the vertical axis and 0.5 on the horizontal axis where it arcs across the graph and comes to an end at the points of 21 on the vertical axis and about 3 on the horizontal axis.

Figure 34. Temperature gradient in a 50-millimeter thick specimen starting at 44 degrees Celsius, air temperature of 22 degrees Celsius, RH of 29 percent, and windspeed of 4.6 miles per second. Graph.

This figure is a graph that shows one distinct blue line descending from the points of zero on a graph and sloping down to a plateau at the bottom of a graph. The vertical axis of this graph ranges from negative 25 to 5 and represents Temperature Difference in degrees Celsius, while the horizontal axis of this graph (running perpendicular to zero point on the vertical axis, and located at the top of the graph) ranges from zero to 12 and represents time in minutes. The blue line begins at the points of zero on both the vertical and horizontal axes. From there is descends in a steep slope to the points of negative 20 on the vertical axis and 4 on the horizontal axis where it plateaus and runs in a near straight line before it ends at the points of negative 20 on the vertical axis and 10 on the horizontal axis.

 


The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT).
The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT). Provide leadership and technology for the delivery of long life pavements that meet our customers needs and are safe, cost effective, and can be effectively maintained. Federal Highway Administration's (FHWA) R&T Web site portal, which provides access to or information about the Agency’s R&T program, projects, partnerships, publications, and results.
FHWA
United States Department of Transportation - Federal Highway Administration