Abstract

	Chemical resistance of auger  grouts   .  Field samples were collected and cured for 28 days in 
moist environment  and tested in different chemical solutions . Chemical solutions used were Hydrochloric 
acid (HCl), Sulfuric acid (H2SO4)at a pH of 2 and 4; and Sodium chloride (NaCl), Sodium sulfate 
(Na2SO4 ) at a concentration of 0.5% and 2%. Control tests were performed with potable water. Three 
parameters were studied; (1) change in weight (2) Leaching of calcium (3) pulse velocity.  . An increase in 
weight was observed in most  cases compared to tap water . A maximum of 3.9% weight gain were 
observed with  2% NaCl , and  a decrease in weight was observed in the case of H2SO4 at a pH of 2, 
Na2SO4  at a conc. of 0.5% and 2%, with a maximum decrease of 4.2% for H2SO4 at a pH of 2 and 
Na2SO4  at a conc. of 0.5%.  Deterioration of the specimens was accelerated by the presence of ions,  the 
sulfate ion had much worse influence than chloride ion . There is an increase in calcium leaching with time, 
maximum leaching was observed in H2SO4 environment at a pH of 2,  in a period of ten months. The pulse 
velocity was 4100 m/s and was constant with time .

1. Introduction 
	Piles deep in the ground can be exposed to various kinds of chemical environments , the reactions 
between them leads to the premature degradation of the structure .  HCl (pH = 4) , H2SO4 (pH = 4) , NaCl 
(0.5% ) and Na2SO4 ( 0.5% ) were chosen to simulate the natural  surroundings, whereas  HCl (pH = 2) , 
H2SO4 (pH = 2 )  NaCl (2%) and Na2SO4 (2% ) were chosen to accelerate the chemical reaction speed.

2. Testing program
	The grouts specimens are rich in cement and fly ash , they were taken from the different depth of 
the auger cast piles  and casted to 3" by 6"  cylinders , after 28 days standard moisture room curing , they 
were immersed into a selected test reagents (prepared by deionized water to full the height in a closed 
plastic bottle )so that the specimens are exposed to the chemical reagent liquid phase .  In this test, 76 mm 
(3-inch) x 152 mm (6-inch) cylindrical cement grouts specimens were used. Specimens were prepared by 
different depth of field casted piles . 1) Leaching of calcium  (2) weight  change (3) pulse velocity .  Four 
test reagents selected for this study are (1) HCl (pH = 2 and 4 ); (2) H2SO4 (pH = 2 and 4) ; (3) NaCl 
(0.5% and 2%) and (4)Na2SO4 (0.5% and 2% )  , Control tests were performed with Tap water. Total of 25 
specimens were tested under these conditions
 
3. Results
	There is an increase in weight (Figure 1.) in the case of HCl (pH = 2, pH = 4) H2SO4 (pH = 4), 
0.5% NaCl , 2% NaCl  compared to tap water, whereas in the case of H2SO4 (pH = 2) and 0.5% Na2SO4, 
2% NaSO4 there is decrease in the weight with time.

	Maximum weight gain of 3.9% was observed in the case of  2% NaCl , whereas there was 4.2% 
weight loss in the case of H2SO4 (pH = 2) and  0.5% Na2SO4 , In 2% Na2SO4 three specimens failed in 8-
10 months by breaking into two equal parts . That show all the ions accelerate deterioration of the grout 
specimens, and the sulfate ion has much more influence than chloride ion. 
	In all the cases, there are increase in calcium leaching with time,  maximum of 0.6%(Based on the 
weight of specimens ) or 6.7% (Based on the total calcium mass in the specimens) of the calcium leached 
out in the first ten months  was  observed in the case of H2SO4 (pH = 2). the leaching of calcium the 
H2SO4 is much more than the HCl  medium.  especially while the concentration is high, whereas the 
calcium leached out in NaCl is more than NaSO4 medium, especially while the concentration of the media 
is low.
	The pulse velocity of the auger cast grouts was approximately 4100 m/s (13451 ft/s) , the 
coefficient of variance was 2% . The pule velocity did not change in ten months except those failed 
specimens which were immersed in NaSO4 media were about 3000 m/s  after  brake down.
 
4. Conclusion
1. All the ions accelerated the deterioration of the grout specimens, and the sulfate ion had much more 
worse influence than chloride ion. 
2. Calcium leaching increases with time, maximum of 0.6% of the calcium of the weight ( 6.7% of total 
calcium )   leached in the first eighth months  was observed in H2SO4 (pH = 2). 
3. The pulse velocity of the auger cast grouts was approximately 4100 m/s, it remains unchanged in the 
first ten  months except for those specimens that failed .

5. References 

Anik Delagrave , Michael Pigeon, Jacques Marchand and Eliane Revertegat , Influence of chloride ions and 
pH level on the durability of high performance cement pastes (Part II)  ,  Cement and Concrete  Research , 
Vol. 26, No. 5, pp. 749-760 (1996).