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Guides from the field and the lab
Written by the CMT Field Desk — the certified technicians and laboratory staff who test concrete and soil on jobsites every day. No product pitches — what the tests are, when they happen, what they cost, and what to do when a result comes back wrong.
October 28, 2026 · 8 min read
A field-to-lab walkthrough of composite gradation testing under the two ASTM standards that replaced D422, covering sieve analysis, hydrometer procedures, and how results govern select fill acceptance.
October 26, 2026 · 8 min read
A boring log tells a complete story about what lies beneath a site; this guide walks you through reading every column, symbol, and number with the same eye a geotechnical technician uses in the field.
October 23, 2026 · 15 min read
From determining the right lime percentage with the Eades-Grim pH test to verifying compaction and unconfined compressive strength in the field, this guide walks through every testing stage for lime and cement stabilized subgrade.
October 22, 2026 · 15 min read
A field-desk guide to identifying, testing, and mitigating Beaumont Formation expansive clays across the Houston region—covering plasticity index, potential vertical rise, lime stabilization, and post-tensioned slab design inputs.
October 21, 2026 · 8 min read
Understanding what your soil's plasticity index actually means—before grading begins—can save a project from heave, rejection of fill, or a failed lime-stabilization spec.
October 19, 2026 · 8 min read
Field moisture governs whether compaction effort produces density or just wasted passes — here is how we measure it, interpret it, and use it to keep earthwork on track.
October 16, 2026 · 4 min read
Ninety-five percent compaction is a specification floor, not a fixed target — the reference density, moisture window, and lift thickness all determine whether your soil actually gets there.
October 15, 2026 · 9 min read
A field-by-field explanation of nuclear density testing: what the gauge is measuring, how geometry changes the result, and what a passing compaction number actually requires.
October 14, 2026 · 14 min read
A field-desk breakdown of the standard and modified Proctor tests—covering compactive energy, curve interpretation, oversize correction, and how to match the right standard to your project specification.
September 14, 2026 · 10 min read
Which soil tests a Houston-area project actually needs — geotechnical borings, Proctor and density, Atterberg limits, select fill verification — why Gulf Coast clay drives all of it, and how the testing is scheduled and priced.
May 7, 2025 · 7 min read
A practitioner's walkthrough of every test in a standard soil lab analysis battery, how samples move through the laboratory, and how the final report drives decisions on fill, subgrade, and foundation design.
April 18, 2025 · 4 min read
ASTM D2216 is the laboratory reference for moisture content because it measures water mass directly — every indirect method in geotechnical work is calibrated against it.
April 13, 2025 · 4 min read
A field-desk breakdown of the plastic limit test: how we run it, how we calculate the result, and why geotechnical engineers and contractors need the number.
April 13, 2025 · 7 min read
Wet washing over the No. 200 sieve captures fines that cling to coarser particles and would survive dry sieving—here is how to run the test correctly from sample prep through final reporting.
April 13, 2025 · 7 min read
A field-desk walkthrough of ASTM D1140 washing procedure, from sample preparation through calculation, explaining why percent passing the No. 200 sieve controls compaction and fill acceptance decisions.
April 13, 2025 · 7 min read
A practical walkthrough of ASTM D4944 calcium carbide testing—how to run it correctly in the field, how to interpret the gauge, and when oven-dry verification is mandatory.
March 6, 2025 · 7 min read
A field-desk walkthrough of ASTM D4318 testing — Casagrande cup, thread rolling, PI calculation, and what the plasticity chart tells you about Houston-area expansive clays.
October 13, 2026 · 13 min read
A field-level guide to flatness, levelness, compressive strength scheduling, and special inspection frequency for mission-critical slab construction.
October 6, 2026 · 9 min read
Walk through every line of a ready-mix submittal the way a special inspector would — so problems get resolved on paper, not in the field after the pour.
October 5, 2026 · 5 min read
A concrete test report contains roughly a dozen data fields; knowing what each one means lets you catch a failing result or a procedural error before it becomes a dispute.
October 2, 2026 · 4 min read
ACI 318 §26.12 sets three triggers for when a strength test is required; IBC 1705.3 adds inspection obligations that directly affect how you schedule your testing lab.
October 1, 2026 · 7 min read
Concrete sampling under ASTM C172 looks simple until you understand how much a bad sample can misrepresent a perfectly good load — here is how to do it correctly.
September 30, 2026 · 8 min read
A field-level walkthrough of ASTM C138 density, yield, and gravimetric air testing — so you can spot a short load or a mix problem before the truck leaves.
September 29, 2026 · 8 min read
A field-to-lab walkthrough of ASTM C78 beam testing for pavement concrete, covering specimen handling, third-point loading mechanics, modulus of rupture acceptance criteria, and how MR relates to compressive strength.
September 28, 2026 · 8 min read
When ambient temperatures drop below 40 °F, concrete testing stops being routine — here is how ACI 306, field-cured cylinders, and the maturity method work together to keep a pour safe.
September 25, 2026 · 15 min read
A field-level guide to managing hot weather concrete in Texas — covering ACI 305 limits, placement temperature maximums, testing protocols, and curing strategies for coastal humidity and inland wind.
September 23, 2026 · 4 min read
A single low break doesn't condemn a pour, but it does start a mandatory sequence — here's how ACI 318 and ASTM C42 walk you through it.
September 22, 2026 · 8 min read
A practitioner's walkthrough of ASTM C39 cylinder breaks: when to test, how caps affect results, what fracture patterns mean, and how ACI 318 defines passing strength.
September 21, 2026 · 8 min read
A field-to-lab walkthrough of ASTM C31 procedures—covering mold filling, initial curing temperatures, transport rules, and why standard-cure and field-cure sets serve different purposes.
September 20, 2026 · 7 min read
A field-by-field walkthrough of ASTM C143 slump testing: how we run the test, how we read the result, and exactly what the tolerances mean for your pour.
September 20, 2026 · 7 min read
Choosing the wrong air content test method wastes time and produces unreliable data — here is how to match ASTM C231 or C173 to your aggregate and exposure conditions.
September 14, 2026 · 11 min read
A field-side explanation of concrete testing on construction projects: which ASTM tests run at the truck and in the lab, who orders them, what they cost, how long results take, and what happens when a cylinder breaks low.
May 3, 2025 · 14 min read
From molding cylinders in the field through reading fracture patterns and investigating low breaks, this guide walks through every stage of the ASTM C39 concrete compression test as we run it.
April 21, 2025 · 8 min read
A field-desk breakdown of every test in the standard concrete testing set—who orders them, what the numbers mean, and how to respond when a cylinder comes in low.
March 27, 2025 · 7 min read
From bad cylinder breaks to missed pour windows, here is what separates a concrete testing company that protects your project from one that quietly puts it at risk.
October 7, 2026 · 7 min read
A practical walkthrough of every inspection and testing milestone a special inspector and contractor must coordinate on a post-tensioned slab, from tendon placement through stressing sign-off.
September 14, 2026 · 8 min read
How CMT firms price field technicians, laboratory tests, special inspection, and full-time project testing; the specification items that drive the number; and how to get a proposal you can compare.
May 5, 2025 · 4 min read
The right geotechnical engineering firm protects your foundation budget and schedule; the wrong one leaves you with a report that raises more questions than it answers.
September 3, 2024 · 8 min read
A geotechnical site investigation turns unknown subsurface conditions into engineering data—here is exactly how the field work, laboratory testing, and final report connect to foundation decisions.
February 5, 2021 · 15 min read
From the first boring to the final foundation recommendation, here is how geotechnical engineering works — the field methods, the lab tests, the soil mechanics, and the Gulf Coast clay realities every project team needs to understand.
January 20, 2025 · 13 min read
A straight look at what happens inside a construction materials testing lab, how the equipment and people are supposed to work, and the specific questions that separate a disciplined lab from one that only looks the part.
September 18, 2013 · 14 min read
A plain-language breakdown of what a CMT firm does on active projects, who reads the results, and how owners use testing to protect schedule and structural integrity.
February 26, 2021 · 13 min read
A Phase I environmental site assessment is the standard due-diligence tool for identifying recognized environmental conditions before a property changes hands, gets financed, or breaks ground.
Reference library
Plain-language pages for every method on our laboratory scope — what it measures, how it works, what throws it off.
ASTM C31 · Field Curing Concrete CylindersASTM C39 · Concrete Compressive StrengthASTM C78 · Concrete Flexural StrengthASTM C138 · Concrete Unit Weight & YieldASTM C143 · Concrete SlumpASTM C172 · Sampling Fresh ConcreteASTM C173 · Air Content, VolumetricASTM C231 · Air Content, Pressure MethodASTM C511 · Moist Room & Curing TankASTM C1064 · Fresh Concrete TemperatureASTM C1231 · Unbonded Neoprene CapsASTM C29 · Aggregate Unit Weight & VoidsASTM C117 · Minus No. 200 by WashingASTM C127 · Coarse Aggregate Specific GravityASTM C128 · Fine Aggregate Specific GravityASTM C131 · LA AbrasionASTM C136 · Aggregate Sieve AnalysisASTM C566 · Aggregate Moisture ContentASTM C1026 · Tile Freeze-Thaw ResistanceASTM D75 · Aggregate SamplingASTM D421 · Dry Soil Sample PreparationASTM D422 · Soil Particle-Size AnalysisASTM D558 · Soil-Cement Moisture-DensityASTM D698 · Standard ProctorASTM D854 · Soil Specific GravityASTM D1140 · Soil Fines Content by WashingASTM D1557 · Modified ProctorASTM D2487 · Unified Soil ClassificationASTM D4718 · Oversize Particle CorrectionASTM D6913 · Soil Sieve GradationASTM D6938 · Nuclear Density & MoistureASTM D7928 · Hydrometer AnalysisASTM G51 · Soil pH for CorrosionASTM G57 · Soil Resistivity, Wenner MethodASTM G187 · Soil Resistivity, Soil Box
FAQ
The CMT Field Desk — the NICET- and ACI-certified technicians and laboratory staff who run these tests daily. Drafts are prepared with AI research assistance, and every procedure, threshold, and claim is reviewed and edited by senior staff before publication.
Yes. Link to them freely. If you are an instructor or a chapter advisor and want a printable version or a short Q&A session for students, email info@constructionmaterialtesting.com.
No. They are plain-language overviews. The published ASTM standard is the controlling document for any test we perform.
Each guide shows its published and updated dates. Guides are revised when a referenced standard changes or when readers point out something a practitioner got wrong — corrections go to info@constructionmaterialtesting.com.
Concrete testing (ASTM C31, C39, C143, C231 and the acceptance rules in ACI 318), soil and earthwork testing (ASTM D698, D1557, D6938, D4318, and what a geotechnical report should tell a contractor), special inspection under IBC Chapter 17, and what testing costs and why. New guides are added weekly.
Yes — email info@constructionmaterialtesting.com with the project situation and the specification section, or call (346) 420-5425. Questions that come up repeatedly become the next guide.
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Or call (346) 420-5425 · info@constructionmaterialtesting.com
