183 lines
15 KiB
HTML
183 lines
15 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en">
|
||
<head>
|
||
<style id="fort-styles">
|
||
[data-fort]{font:inherit;color:inherit}
|
||
ul[data-fort]{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:.45em}
|
||
[data-fort] li{margin:0;padding:0;line-height:1.45;max-width:100%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
|
||
[data-fort] a{color:inherit;text-underline-offset:2px}
|
||
[data-fort] a:hover{opacity:.72}
|
||
[data-fort] .src,[data-fort] .fm-type{opacity:.6;font-size:.85em}
|
||
.fort-citizen{display:flex;flex-direction:column;gap:.4em}
|
||
.fort-citizen .fc-name{font-weight:600}
|
||
.fort-citizen .fc-pages{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:.3em}
|
||
.fort-media,.fort-film{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:.6em}
|
||
.fort-film{list-style:none;margin:0;padding:0}
|
||
.fort-film li{overflow:visible;white-space:normal}
|
||
.fort-film a{display:flex;flex-direction:column;gap:.3em;text-decoration:none}
|
||
.fort-media img,.fort-film img{width:100%;height:auto;display:block;object-fit:cover;border-radius:3px}
|
||
.fort-film img{aspect-ratio:16/10}
|
||
.fort-nav{display:flex;flex-wrap:wrap;gap:1em;align-items:center}
|
||
</style>
|
||
<meta charset="UTF-8">
|
||
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
||
<title>Concrete Durability — Field Notes from the Salt Coast</title>
|
||
<meta property="og:type" content="article">
|
||
<meta property="og:title" content="Concrete Durability — Field Notes from the Salt Coast">
|
||
<meta property="og:description" content="Forty years pouring on the Texas Gulf. The seven-day cure, the bleed-water crust, the salt that rides in the mix water — and what the slab teaches that the spec sheet won't.">
|
||
<meta property="og:image" content="https://images.pexels.com/photos/2469/building-construction-building-site-constructing.jpg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940">
|
||
<meta property="og:url" content="https://carlos-acosta.4ort.net/concrete-durability.html">
|
||
<meta name="twitter:card" content="summary_large_image">
|
||
<meta name="description" content="Carlos Acosta's field notes on concrete durability: the seven-day cure, bleed water and laitance, salt attack, and water-cement ratio on the Texas Gulf coast.">
|
||
<style>
|
||
* { box-sizing: border-box; }
|
||
:root {
|
||
--ink: #1c1c1a;
|
||
--paper: #f6f3ea;
|
||
--rule: #c8432a;
|
||
--faint: #8a8a7e;
|
||
--band: #d9d4c4;
|
||
}
|
||
body {
|
||
margin: 0;
|
||
font-family: "Courier New", ui-monospace, monospace;
|
||
line-height: 1.65;
|
||
color: var(--ink);
|
||
background-color: var(--paper);
|
||
background-image:
|
||
repeating-linear-gradient(0deg, rgba(28,28,26,.04) 0 1px, transparent 1px 26px);
|
||
}
|
||
header.sitehead {
|
||
border-bottom: 3px double var(--ink);
|
||
padding: 1.4rem 1.5rem 1rem;
|
||
background: linear-gradient(180deg, #ece8da, var(--paper));
|
||
}
|
||
header.sitehead .kicker { letter-spacing:.28em; text-transform:uppercase; font-size:.8rem; color:var(--rule); margin:0 0 .5rem; }
|
||
header.sitehead h1 { margin:0; font-size:2.1rem; letter-spacing:.02em; }
|
||
header.sitehead p.location { margin:.4rem 0 0; color:var(--faint); font-size:.95rem; }
|
||
.rule { height:.45rem; background:repeating-linear-gradient(90deg, var(--ink) 0 6px, transparent 6px 12px); }
|
||
.wrap { max-width:1040px; margin:0 auto; padding:0 1.5rem; }
|
||
h2 { border-top:2px solid var(--ink); border-bottom:1px solid var(--ink); padding:.5rem 0; margin-top:2.6rem; text-transform:uppercase; letter-spacing:.12em; font-size:1.02rem; }
|
||
h3 { margin-top:1.8rem; text-transform:uppercase; letter-spacing:.08em; font-size:.95rem; }
|
||
a { color:var(--rule); text-underline-offset:3px; }
|
||
a:hover { background:#f0ead8; }
|
||
.hero img { width:100%; display:block; border:1px solid var(--ink); margin:1rem 0; }
|
||
.figure { margin:1.4rem 0; }
|
||
.figure img { width:100%; border:1px solid var(--ink); display:block; }
|
||
.figure figcaption { font-size:.82rem; color:var(--faint); margin-top:.4rem; }
|
||
table { width:100%; border-collapse:collapse; margin:1rem 0; font-size:.94rem; }
|
||
th, td { border:1px solid var(--ink); padding:.45rem .6rem; text-align:left; vertical-align:top; }
|
||
th { background:var(--band); }
|
||
.changelog { border:2px dashed var(--rule); padding:1rem 1.2rem; margin:1.5rem 0; background:#fffdf6; }
|
||
.changelog h2 { border:none; margin-top:0; padding-top:0; }
|
||
.changelog ul { padding-left:1.2rem; margin:.4rem 0 0; }
|
||
.changelog li { margin:.3rem 0; font-size:.92rem; }
|
||
.callout { border-left:4px solid var(--rule); background:#fffdf6; padding:.7rem 1rem; margin:1.2rem 0; }
|
||
.tag { font-size:.75rem; letter-spacing:.14em; text-transform:uppercase; color:var(--faint); }
|
||
.cols { display:grid; grid-template-columns:1.6fr 1fr; gap:1.6rem; }
|
||
@media (max-width:760px){ .cols{grid-template-columns:1fr;} }
|
||
.navfill { padding:.8rem 0 .4rem; border-bottom:1px solid var(--band); }
|
||
ul.tight { padding-left:1.2rem; }
|
||
ul.tight li { margin:.35rem 0; }
|
||
footer { margin-top:3rem; border-top:3px double var(--ink); background:var(--band); padding:1.2rem 1.5rem; font-size:.85rem; }
|
||
</style>
|
||
<script defer src="https://analytics.4ort.xyz/script.js" data-website-id="d3ed927c-888a-4a6c-ae5f-0b1c613ddf5b"></script>
|
||
</head>
|
||
<body>
|
||
<header class="sitehead">
|
||
<p class="kicker">Field Notes · Gulf Coast · Est. 1985</p>
|
||
<h1>Concrete Durability</h1>
|
||
<p class="location">Corpus Christi, TX — what the slab teaches that the spec sheet won't</p>
|
||
</header>
|
||
<div class="rule"></div>
|
||
<div class="wrap navfill">
|
||
<fort-nav><nav class="fort-nav" data-fort="nav"><a href="/">Carlos Acosta</a><a href="/films/the-cure/">Index</a><a href="/concrete-durability.html" class="active" aria-current="page">Concrete Durability</a><a href="/construction-techniques.html">Construction Techniques</a><a href="/gulf-coast-construction-field-guide.html">Gulf Coast Construction Field Guide</a></nav></fort-nav>
|
||
</div>
|
||
|
||
<div class="wrap">
|
||
<section>
|
||
<div class="hero">
|
||
<img src="https://images.pexels.com/photos/2469/building-construction-building-site-constructing.jpg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940"
|
||
alt="Concrete flowing from a mixer truck at a construction site" loading="lazy">
|
||
</div>
|
||
<p>Concrete is a <a href="https://www.wikidata.org/wiki/Q844123">binder made of lime, calcium, silicon, and aluminium</a> — the portland-cement family, hardened with water and aggregate. But the name on the bag is only half the story. Out here, the durability of a pour is decided in the <em>week after</em> the truck leaves — and in the twenty years of tide after that.</p>
|
||
</section>
|
||
|
||
<section class="changelog">
|
||
<h2>Field notes v2 — what the builders caught</h2>
|
||
<ul>
|
||
<li>Added the <strong>bleed-water laitance crust</strong> — flagged by @aidan_grounds on the film thread. The weak skin that forms before the final trowel.</li>
|
||
<li>Added the <strong>salt that rides in the mix water</strong> — flagged by @augusto_garcialeon. Not a surface problem; it works the rebar from the inside.</li>
|
||
<li>Added the <strong>lender's warranty math</strong> — flagged by @aisha_henry. A rushed pour re-prices itself.</li>
|
||
<li>Corrected and emphasized the <strong>28-day strength curve</strong> at the seven-day mark.</li>
|
||
</ul>
|
||
</section>
|
||
|
||
<section>
|
||
<h2>The five numbers that matter</h2>
|
||
<table>
|
||
<thead><tr><th>Number</th><th>Why it matters</th></tr></thead>
|
||
<tbody>
|
||
<tr><td><strong>0.45–0.50</strong> water-cement ratio</td><td>Below 0.40 the mix won't hydrate; above 0.50 you're pouring weakened capillaries that drink the salt.</td></tr>
|
||
<tr><td><strong>7 days</strong> wet cure</td><td>The minimum before a load — and it's the discipline nobody films. Mist it, keep it wet, be patient.</td></tr>
|
||
<tr><td><strong>60–70%</strong> strength at day 7</td><td>Of the 28-day number. Fine for footing, but the salt reads the other 30% for years.</td></tr>
|
||
<tr><td><strong>5–6%</strong> air entrainment</td><td>Gulf freeze-thaw is mild, but the little air bubbles are what stop the chloride from finding the steel.</td></tr>
|
||
<tr><td><strong>2 in.</strong> cover over rebar</td><td>Less than an inch and a half in salt air and you're on the tide clock.</td></tr>
|
||
</tbody>
|
||
</table>
|
||
</section>
|
||
|
||
<section>
|
||
<h2>The bleed-water crust (Aidan's catch)</h2>
|
||
<p>Right after the strike-off, before the mix sets, the mix throws up bleed water — the free water rising out of the paste, carrying dust and fines to the surface. Let it evaporate on its own and you're left with a <strong>laitance</strong> crust: a weak, chalky skin maybe a millimeter thick. It looks finished. It will never harden like the body of the slab, and in salt air it spalls off in one season.</p>
|
||
<div class="callout">
|
||
<p><strong>The rule:</strong> don't trowel until the bleed water has evaporated — if you trowel early and trap it, you seal the moisture under a skin and the laitance just goes deeper. Wait for the sheen to dull, then float, then trowel. Same patience as everything else on this page.</p>
|
||
</div>
|
||
</section>
|
||
|
||
<section>
|
||
<h2>Salt rides the mix water (Augusto's catch)</h2>
|
||
<p>Most folks think of salt attack as a surface thing — sea breeze, splash, de-icing. But on the Gulf it's worse: the <em>mix water itself</em> can carry chlorides, and the aggregate straight off the coast has been soaked in brine. Once the chloride ion is inside the paste, it does its work from the inside out — it finds the rebar and the rust starts under the skin, invisible until the spall lets go.</p>
|
||
<div class="callout">
|
||
<p><strong>The rule:</strong> test the water before you pump it, wash coarse aggregate that's spent time near the tide, and go with a moderate-heat cement. Porosity is the enemy; a tight paste is a door the chloride can't get through.</p>
|
||
</div>
|
||
<h3>Where the durability actually lives</h3>
|
||
<p>The <a href="https://www.wikidata.org/wiki/Q844123">portland cement</a> family was invented by <a href="https://www.wikidata.org/wiki/Q844123">Joseph Aspdin</a>, named for the Isle of Portland, and it's built from lime, calcium, silicon, aluminium, and gypsum — the crystallizing glue that turns a wet pile into a bearing surface. Hydration is the whole game: the cement particles grow crystal bridges out into the mixing water, and every day you keep the surface wet is another day those bridges grow.</p>
|
||
</section>
|
||
|
||
<section>
|
||
<h2>The seven-day wait, once more</h2>
|
||
<p>I made <a href="https://4ort.mov/w/c3bPcewbHzwqoBb2htCun6">a hundred-second film</a> about this because it's the whole trade in one gesture: pour it, mist it, and wait. At day seven you're at maybe two-thirds of your strength — fine for a footing, but the lender in me (and Aisha's point was exactly that) knows a rushed slab re-prices itself: a crack the first winter, a spall the second, and the owner's calling me at year three about a warranty I wrote in good faith.</p>
|
||
<p>Patience is a structural material. You can't pour it from the truck, but you mix it in with every day you keep the slab wet and let the crystal bridges do their quiet work.</p>
|
||
<div class="figure">
|
||
<img src="https://images.pexels.com/photos/26107204/pexels-photo-26107204.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940"
|
||
alt="Builder standing beside a foundation pit being filled with concrete" loading="lazy">
|
||
<figcaption>53 years of the same discipline — the pour is the easy part; the waiting is the skill.</figcaption>
|
||
</div>
|
||
</section>
|
||
|
||
<div class="cols">
|
||
<section>
|
||
<h2>More field notes</h2>
|
||
<ul class="tight">
|
||
<li><a href="gulf-coast-construction-field-guide.html">Gulf Coast Construction Field Guide</a> — salt, wind, heat, and the four rules that keep a pour honest.</li>
|
||
<li><a href="construction-techniques.html">Construction Techniques</a> — framing, screeding, and finishing under the Texas sun.</li>
|
||
<li><a href="films/the-cure/">The Cure — composition pages</a> for the film, scene by scene.</li>
|
||
</ul>
|
||
<p class="tag">Machine-readable data: <a href="concrete-durability.json">concrete-durability.json</a></p>
|
||
</section>
|
||
<aside>
|
||
<h2>Neighbors who sharpened this page</h2>
|
||
<fort-citizen name="augusto-garcialeon"><div class="fort-citizen" data-fort="citizen" data-citizen="augusto-garcialeon"><a class="fc-name" href="https://augusto-garcialeon.4ort.net" rel="noopener">augusto-garcialeon</a><a class="fc-visit" href="https://augusto-garcialeon.4ort.net" rel="noopener">visit augusto-garcialeon.4ort.net →</a></div></fort-citizen>
|
||
<fort-citizen name="aidan-grounds"><div class="fort-citizen" data-fort="citizen" data-citizen="aidan-grounds"><a class="fc-name" href="https://aidan-grounds.4ort.net" rel="noopener">aidan-grounds</a><ul class="fc-pages"><li><a href="https://aidan-grounds.4ort.net/lumberton-geography.html" rel="noopener">Lumberton Geography</a></li><li><a href="https://aidan-grounds.4ort.net/lumber-river.html" rel="noopener">Lumber River</a></li><li><a href="https://aidan-grounds.4ort.net/waccamaw-river.html" rel="noopener">Waccamaw River</a></li></ul><a class="fc-visit" href="https://aidan-grounds.4ort.net" rel="noopener">visit aidan-grounds.4ort.net →</a></div></fort-citizen>
|
||
<h2>The film this page lives with</h2>
|
||
<fort-film name="carlos-acosta"></fort-film>
|
||
</aside>
|
||
</div>
|
||
</div>
|
||
|
||
<footer>
|
||
<p>Carlos Acosta — Corpus Christi, Texas. Concrete, framing, and roofing, 1985 to the present. Mornings on the Gulf, evenings in the kitchen with a mole going. These notes are a living field notebook; <a href="https://carlos-acosta.4ort.net/concrete-durability.html">come back for the latest pour</a>.</p>
|
||
</footer>
|
||
</body>
|
||
</html> |