Present: All the Justices 

TARMAC MID-ATLANTIC, INC. 

v. Record No. 941648 OPINION BY JUSTICE BARBARA MILANO KEENAN 

 June 9, 1995 

SMILEY BLOCK COMPANY 

 FROM THE CIRCUIT COURT OF THE CITY OF LYNCHBURG 

Richard S. Miller, Judge 

 In this case, we consider whether the trial court properly 

sustained a motion to strike, and whether, in connection with 

that ruling, the court abused its discretion in excluding expert 

testimony on the basis that it lacked an adequate foundation. 

 Smiley Block Company, Inc. (Smiley), filed a motion for 

judgment to recover sums due from Tarmac Mid-Atlantic, Inc. 

(Tarmac) in payment for "cupola slag." Tarmac denied it was 

indebted to Smiley and filed a counterclaim asserting various 

theories, including breach of express and implied warranties. 

Tarmac alleged that the slag Smiley provided did not conform to 

industry standards, and that when Tarmac used the slag in its 

manufacture of concrete masonry block, the block developed 

defects known as "pop-outs." 

 At the jury trial, Tarmac's evidence on its counterclaim 

also constituted its sole evidence in defense of Smiley's breach 

of contract action. When the trial court sustained Smiley's 

motion to strike Tarmac's evidence on the counterclaim, it also 

ruled in favor of Smiley on the motion for judgment, finding that 

there were no issues remaining for the jury's determination. We 

review the evidence and all reasonable inferences therefrom in 

the light most favorable to Tarmac. See Medcom, Inc. v. C. 
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Arthur Weaver Co., 232 Va. 80, 82, 348 S.E.2d 243, 245 (1986). 

 James E. Ritter, operations manager of Tarmac's Richmond 

Block plant, testified that he began purchasing slag from Smiley 

around May 1992. Slag is a lightweight aggregate that is 

incorporated together with other materials in the manufacture of 

concrete products. Over the next year, pumice and the slag 

purchased from Smiley were the only lightweight aggregates that 

the Richmond Block plant used in its production. 

 Before Tarmac began to order the slag, Henry Smiley had 

provided Ritter with a bag of the aggregate, a piece of concrete 

block, and a certification stating that the slag met the criteria 

for lightweight aggregates established by the American Society 

for Testing and Materials. In particular, the certification 

stated that the material tested exhibited no pop-outs. Ritter 

testified that, in buying the slag, Tarmac relied on the 

certification and on Smiley's representations as to the quality 

of the material. 

 In early 1993, Tarmac's customers complained to Ritter about 

the block Tarmac had manufactured using Smiley's slag. Ritter 

examined the block used in construction projects and noted popouts, or "small chunks that popped out of the face of the block." 

 To remedy the problem, Tarmac went to the construction projects 

and repaired the block. 

 Ritter then submitted several samples to a laboratory, 

Froehling & Robertson, Inc., to determine the cause of the pop-
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outs. He identified three reports received from Froehling & 

Robertson showing its test results. Ritter stated that he and 

Richard Wright, Tarmac's production manager, obtained the samples 

that were the subject of two reports made in July 1993. The 

first sample was a block containing pop-outs, taken from Tarmac's 

stock, and the second was a bag of slag, taken from slag received 

from Smiley and stockpiled in Tarmac's yard. Wright delivered 

both these samples to Froehling & Robertson. A third report, 

made in September 1993, provided an analysis of two slag samples, 

which Ritter stated he collected from Tarmac's stockpile and 

personally delivered to Froehling & Robertson. 

 Ritter stated that Tarmac regularly hired a trucking company 

to deliver shipments of slag purchased from Smiley to Tarmac's 

plant, where Tarmac stored the slag in open bins. The samples of 

slag provided to Froehling & Robertson came from these 

stockpiles. Ritter did not obtain a sample directly from 

Smiley's yard for testing. He said that he did not know what 

other materials might have been carried in the delivery trucks, 

nor whether foreign materials such as seeds or dust might have 

blown into the slag while it was in Tarmac's stockpiles. Ritter 

acknowledged that pop-outs in the block could be caused by the 

introduction of any material that tends to expand, such as a 

seed. 

 August A. Thieme of Froehling & Robertson, the author of the 

test reports, qualified as an expert in inorganic and analytical 
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chemistry. Thieme stated that each sample provided to him by 

Tarmac contained high levels of magnesium.*

 He concluded that 

magnesium compounds in the slag had caused the pop-outs in the 

manufactured block. Thieme explained that when slag is derived 

from dolomitic-type limestone, the magnesium contained in the 

stone may be subjected to excessive temperatures, or 

"overburning." As a result, the magnesium is slow to rehydrate 

upon exposure to moisture and carbon dioxide, and it remains in 

an unstable state. In the process of rehydration, the material 

expands, increases in volume, and exerts pressure, leading to a 

"propelling of the surface from the block." 

 *Ritter testified that when he provided two slag samples to 

Thieme for his September 1993 report, he also delivered a sample 

of bottom ash received from a Tarmac plant in South Carolina, 

which was submitted to be tested for reasons not revealed by the 

record. Thieme found high levels of magnesium in all three 

samples. He stated that the entire group of samples tested for 

his September 1993 report was labeled "slag aggregate," and that 

he was not aware that one of the samples was actually bottom ash. 

 Smiley cites these facts in support of its argument that 

Thieme's testimony did not have an adequate foundation. However, 

we do not consider this evidence in evaluating the admissibility 

of the testimony, because neither the record nor Smiley's 

argument on appeal explains the significance of the cited facts. 
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 Thieme stated that he had considered whether other 

components of the block, such as cement and additives, or the 

presence of contaminants in the slag, could have been the source 

of the pop-outs. He acknowledged that in testing material such 

as this, it is necessary to consider matters such as handling, 

sampling, storage, and transportation. However, Thieme testified 

that he had not identified any other cause of the high magnesium 

content he observed, and he concluded that the slag material must 

have been the only source, since any source other than the slag 

"would almost have to be a burned lime of some sort." Thieme 

also stated that, although unstable burned lime is manufactured 

for certain uses, it is shipped in individually sealed containers 

and typically is not carried in open trucks. 

 Thieme stated that all the materials tested were delivered 

to him in his laboratory. He acknowledged that he would have 

preferred to draw a slag sample directly from Smiley's yard for 

testing. 

 During trial, the court took under advisement Smiley's 

motions to exclude Thieme's testimony based on a lack of adequate 

foundation. Smiley argued that the samples Thieme analyzed had 

been exposed to many sources of contamination while they were out 

of Smiley's possession and control, so that Thieme's testimony 

was unreliable and speculative. After Ritter and Thieme had 

testified, and before Tarmac presented evidence of damages, 

Smiley moved to strike Tarmac's evidence on its counterclaim. 
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Although Smiley raised various arguments, the trial court's 

comments show that it sustained the motion based on its 

conclusion that Thieme's testimony was inadmissible. 

 Citing Mary Washington Hospital, Inc. v. Gibson, 228 Va. 95, 

319 S.E.2d 741 (1984), the trial court stated that, in the 

present case, "too many variables" rendered the expert's 

testimony "open to speculation," because the evidence raised 

questions about conditions that may have affected the slag during 

its transportation and storage. The trial court noted that 

Tarmac's "own expert is saying that he would have preferred to 

have come up here and gotten it at Smiley, and [it] is obvious 

why he would have preferred that, because the test itself would 

have been much more reliable." The trial court granted the 

motion to strike, concluding that "in this case, because of the 

nature of the claim[,] fundamental fairness dictates that you 

have got to show a better chain than that." 

 On appeal, Tarmac argues that the trial court erred in 

granting Smiley's motion to strike. In particular, Tarmac 

contends that Thieme's testimony regarding the nature of the 

substances he tested was admissible, and if the trial court had 

not improperly excluded it, Tarmac would have presented a prima 

facie case on its breach of warranty claim. In response, Smiley 

reasserts the arguments it raised in the trial court, contending 

that Thieme's testimony was speculative because it was based on 

an assumption, not supported by the evidence, that the slag 
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samples he examined were in the same condition as when they left 

Smiley's yard. We disagree with Smiley. 

 "The admission of expert testimony is committed to the sound 

discretion of the trial judge, and we will reverse a trial 

court's decision only where that court has abused its 

discretion." Brown v. Corbin, 244 Va. 528, 531, 423 S.E.2d 176, 

178 (1992). As a general rule, a litigant is entitled to 

introduce all competent, material, and relevant evidence tending 

to prove or disprove any material issue raised, unless the 

evidence violates a specific rule of admissibility. Barnette v. 

Dickens, 205 Va. 12, 15, 135 S.E.2d 109, 112 (1964); McNeir v. 

Greer-Hale Chinchilla Ranch, 194 Va. 623, 628-29, 74 S.E.2d 165, 

168-69 (1953). 

 Expert testimony is admissible in civil cases to assist the 

trier of fact, if the evidence meets certain fundamental 

requirements, including the requirement that it be based on an 

adequate foundation. See Code §§ 8.01-401.1, 8.01-401.3; Lawson 

v. Doe, 239 Va. 477, 482-83, 391 S.E.2d 333, 336 (1990); Clark v. 

Chapman, 238 Va. 655, 664-65, 385 S.E.2d 885, 891 (1989). Expert 

testimony is inadmissible if it is speculative or founded on 

assumptions that have no basis in fact. See Gilbert v. Summers, 

240 Va. 155, 159-60, 393 S.E.2d 213, 215 (1990); Cassady v. 

Martin, 220 Va. 1093, 1100, 266 S.E.2d 104, 108 (1980). 

 In addition, such testimony should not be admitted unless 

the trial court is satisfied that the expert has considered all 
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the variables bearing on the inferences to be drawn from the 

facts observed. See Swiney v. Overby, 237 Va. 231, 233-34, 377 

S.E.2d 372, 374 (1989); Grasty v. Tanner, 206 Va. 723, 727, 146 

S.E.2d 252, 255 (1966). Finally, the trial court should refuse 

to admit expert testimony unless there is proof of a similarity 

of conditions existing at the time of the expert's tests and at 

the time relevant to the facts at issue. Runyon v. Geldner, 237 

Va. 460, 463-64, 377 S.E.2d 456, 458-59 (1989). 

 These principles were applied in Mary Washington Hospital, 

228 Va. at 99, 319 S.E.2d at 743. In that case, this Court held 

inadmissible evidence regarding an architect's tests made at the 

location where the plaintiff had fallen on a sidewalk, because 

there was insufficient proof that the site had not changed 

materially during the 23 months between the accident and the 

inspection. The uncontradicted evidence showed there had been 

construction work in the area during that time, and that the 

section of concrete on which the plaintiff slipped had been 

destroyed. These changes constituted "missing variables" not 

considered by the architect, so that the delayed inspection of 

the sidewalk was not reliable and probative evidence of its 

condition at the time of the accident. Id. 

 In contrast, the evidence in the present case showed that 

the condition of the slag was essentially the same at the time of 

its shipment and at the time of the expert's testing. Ritter's 

testimony regarding the transportation, storage, and sampling of 
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the slag was prima facie evidence that the samples Thieme tested 

had originated in the slag supplied by Smiley. Further, it could 

be inferred that, with the passage of time, the samples would 

become more stable rather than less so, due to the tendency of 

the overburned magnesium to rehydrate slowly. Thus, unstable 

magnesium found at the time of testing would have been unstable 

at an earlier time, as well. 

 In addition, there was no positive evidence showing any 

alteration of the slag or any intermixture of foreign materials, 

other than the fact that, in one of the samples, the slag was 

present together with other materials in a finished concrete 

block. Further, the evidence showed that Thieme had considered 

and excluded other variables that would affect his conclusions, 

such as the possibility that materials other than slag were the 

source of the high levels of magnesium. Thus, we hold that 

Tarmac adequately provided a foundation for the admission of 

Thieme's test results. 

 Although Smiley argues that in various respects Thieme's 

conclusions were open to challenge, any such weaknesses in his 

testimony were not grounds for its exclusion, but were matters 

properly to be considered by the jury in determining the weight 

to be given the evidence. See Ford Motor Co. v. Bartholomew, 224 

Va. 421, 430, 297 S.E.2d 675, 680 (1982); Martin v. Penn, 204 Va. 

822, 826, 134 S.E.2d 305, 307 (1964). Therefore, we conclude 

that the trial court abused its discretion in refusing to admit 
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Thieme's testimony. 

 Smiley further argues that, even if Thieme's testimony had 

been admitted at trial, Tarmac failed to present a prima facie 

case on its breach of warranty counterclaim. Smiley contends 

that Tarmac's evidence did not show either that a warranty was 

made or that Tarmac relied on any such warranty. We disagree. 

Tarmac presented evidence that Ritter received and relied on 

samples of block and slag and a certification stating, among 

other things, that the material tested had no pop-outs. Granting 

Tarmac the benefit of all reasonable inferences to be drawn from 

the evidence, we find that Tarmac presented sufficient evidence 

on these issues to create a question for the jury's 

determination. See Code § 8.2-313. 

 For these reasons, we conclude that the trial court erred in 

sustaining Smiley's motion to strike Tarmac's counterclaim. We 

will reverse the trial court's judgment and remand this case for 

a new trial consistent with the principles expressed in this 

opinion. 

Reversed and remanded.